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  1. 3 points
    These are "how to" or explanatory guides on metal detecting and gold prospecting themes written by Steve Herschbach. Many were written in response to questions asked on this websites forum. Each article focuses on a single subject and they are meant to be relatively short but cover the topic well. There is information both for beginners plus advanced topics for the pros. Metal Detecting Steve's Guide to Headphones for Metal Detecting Steve’s Guide to Metal Detecting for Gold Nuggets Steve's Guide to Gold Nugget Detectors Steve's Guide to Metal Detectors with Reliable Target ID Numbers Steve’s Guide to VLF Metal Detectors and “More Depth” Steve's Guide to Metal Detector Search Coil Compatibility Steve's Guide to VLF Concentric vs DD Search Coils Steve's Guide to "Search Coils Are Not Antenna" Steve's Guide to Variations in Coil Performance Steve's Guide to Threshold Autotune, SAT & V/SAT Steve's Guide to Metal Detector Mixed Modes Steve's Guide to Detecting Gold Jewelry Versus Aluminum Steve’s Guide to Why Detecting Thin Gold Chains Is Difficult Steve's Guide to Multifrequency Metal Detectors Steve’s Guide to Metal Detector Discrimination Basics Steve's Guide to Target Masking Differences Euro vs U.S. Steve’s Guide to Why Weak Non-Ferrous Targets Read As Ferrous Steve's Guide to Why Some Ferrous Reads Non-Ferrous Steve's Guide to Waterproof VLF Metal Detectors Steve's Guide to Beach Detecting For Gold Prospectors Steve's Guide to Gold Nugget Target ID Numbers Steve’s Guide To Why Detecting Tiny Gold In A Bottle Is Difficult Steve's Guide to VLF vs PI Depth Difference Steve's Guide to Pulse Induction Ground Balance Steve's Guide to Pulse Induction Discrimination Steve's Guide to Long Range Locators (LRLs) Steve's Guide to Beach Detecting For Gold Prospectors Steve's Guide to the Fisher CZ Steve's Guide to Differences Between Minelab SD, GP, & GPX Steve's Guide to Minelab GPX Timings Steve's Guide to Ground Tracking As A Filter Steve’s Guide To Detecting Gold In Quartz Rock & Mine Dumps Steve's Guide to Finding Gold Veins With A Metal Detector Steve's Guide to White's Electronics GMT versus MXT Steve's Guide to White's TDI Coin Settings Steve's Guide to Rebuilding The White's GMT White's MXT Engineering Guide Metal Detector Database with User Reviews Prospecting Steve's Guide to How to Pan for Gold Steve's Guide to Suction Gold Dredges Steve's Guide to Where To Prospect For Gold Gold Prospecting Research Material For Alaska General Other Metal Detecting & Prospecting Websites Steve's Guide to Successful Rock Tumbling Metal Detecting & Prospecting Library Catalogs, Brochures, User Guides, & Owner's Manuals
  2. 1 point
    This page is a free service to help people find mining claims for sale or lease in Alaska. Listings here may be deleted after 6 months but in general the ads are left up until you notify me that you want them removed. To have your ad listed here, email your ad with details. Use the existing ads as your template. Note that since I am a prospector it can take a week or more for listings to be posted. VERY IMPORTANT! DetectorProspector.com and Herschbach Enterprises take no responsibility for the accuracy of the information presented here. A listing on this page is in no way an endorsement or recommendation of the property listed. Contact the person listing the claim if you want more information. Research all claims thoroughly before purchase. Read Investigate That Claim Before You Buy. Also see Gold From Water and other mining scams (look for Free Downloads pdf link). If you have any doubt about what you are doing consider hiring a qualified person or company to validate a potential claim purchase. If you know of a listing here that you believe to be fraudulent in any way please alert us at the email address above. Ruby Mining District - Added 6/24/20. Two 40-acre state mining claims in the Ruby Mining District including equipment. I have been running the old timers’ tailings with consistent results over the last 4 years. AK620507 & AK620506 are located along Midnight Creek (great water). There is over 1000 linear feet of tailings along the creek which are anywhere from 20 to 50 feet tall (lots of material). Sale includes Ford 750 Back-hoe-loader, 6-inch water pump, Shaker wash plant, clean up equipment, 1995 Ford E-350 Cube truck, Keene 5-inch suction dredge with 3 stage sluice and air, various tools, hoses, generators, spare parts. Reason for selling is that I am getting older and just can’t work as hard as I used too (Desk job last 26 years). The last several years I have taken about 2 weeks off from my job to work the tailings with the following results: • In 2017 I fed wash plant for 23.5 hours and recovered 3.7 ozt of gold • In 2018 I fed wash plant for 9.0 hours and recovered 1.1 ozt of gold • In 2019 I fed wash plant for 15.3 hours and recovered 2.1 ozt of gold Serious inquires only please. You can email me for more information and pictures at cessnadrivergus@yahoo.com Cell: 612-201-9372 please leave a message if I don’t answer (too many Scammers & Spammers). $29,500 for the claims and equipment. Here are a few links to video of my mine: https://www.youtube.com/watch?v=-95kXz3V0WI https://drive.google.com/file/d/1amiSFI-sPsDn0ORAxl_XJac7PXah6hs9/view?usp=sharing Cherry Creek - Added 6/7/20. I have 7 claims on Cherry Creek South of Boundary, Alaska. There is road access to both ends of the claims they are still mining above these claims there are 6 virgin claims and one that has been mined but needs to be mined again . It produced over 200 oz when it was mined in 1990. I am asking $20,000 per claim, they are very good ground and they are all state claims if interested contact me at websterscrap@yahoo.com 882 Acres on McWilliams - Gold Trail w/Patented Placer Claims (Estate Sale) Click on Lot Links for Approximate Mid-Locations of Listed Lots. Lots start from Headwaters of Claim and continues 7 miles downstream. (HINT: Lot J-22 is farthest, upstream lot and list continues downstream to end lot.) Lot J-22, Lot J-21, Lot J-20, Lot J-17, Lot J-31, Lot J-18, Lot J-16, Lot J-15, Lot J-1, Lot J-30, Lot J-2, Lot J-3, Lot J-4, Lot J-5, Lot J-6, Lot J-7, Lot J-8, Lot J-9, Lot J-10, Lot J-11, Lot J-12, Lot J-13, Lot J-14, USS 6070, Lot J-25, Lot J-27, Lot J-28, Lot J-26, Lot J-24, Lot J-23, Lot J-32, Lot J-33, Lot J-34, Lot J-35, Lot J-36, Lot J-37, Lot J-38, Lot J-39, Lot J-40, Lot J-41, Lot J-42, Lot J-43 Includes any and all abandoned buildings and equipment, without warranty of any kind, 41 Contiguous Claims and USS 6070, encompassing 881.96 acres of Private, U .S. Patent Land running mostly on both sides of John's Creek and Chunilna Creek. Ground Access: 36 mile trail from the loading docks of the Alaska Railroad to the J-2 Claim. Air Access: 2,800' airfield off J-14 and area of USS 6070. (RUNWAY CURRENT CONDITION UNKNOWN) Past Placer Mining Activity Over 6,749.84 Au recovered troy oz. from 361,413 cu. yd. with 5,093 hr. worked. Virgin ground believed to still exist. Value of minerals not given a value in sales price. Title Insured in the amount of the Sales Price. Future Land Individual Sales Forty-one (41) Individual lots approx. 19-20 acre lots already subdivided into 2 Mining Claims; MS224, or 282.84 acres, and MS2252, or 519.14 acres; plus one 79.98 acre lot, USS 6070, all which can be divided into 42 individuals lots, allowing for easier divesting of this investment, in the future. List Price: $1,400,000 Contact Greg Erkins (907) 562-3382 gregerkins@hotmail.com or gerkins@gci.net Greenstone Creek - Added 4/13/20. In the Ruby Mining District. For sale 13 State of Alaska claims enclosing 760 acres of placer and lode claims. The hillside placer ground is very shallow to bedrock. I deal for a small placer operation and hardrock exploration. The extensive list of equipment includes dozers, excavator, loader and many more items. 767 troy ounces of coarse gold was mined in two recent seasons. A potential resource of >900 ounces from 35,000 bank cubic yards of pay gravel (0.03 oz/bcy) has been outlined by test pitting for production in 2020. Fully permitted through 2023. The portable camp of three trailers and one RV motorhome and can comfortably accommodate up to 7 persons. Small generators provide electricity to all buildings. Start mining or detecting gold nuggets this summer. Complete purchase required. Motivated seller. Asking $1,000,000 for the placer, lode, camp and all equipment. Contact Jim Halloran (agent) at augeojim@yahoo.com for more information. Hansen Gold Claims Near Nome - Added 2/26/20. Budd Creek, Windy Creek, Million Creek, Gold Run Creek group North of Nome, Alaska. 34 State of Alaska, 40 acre claims for sale on 2 adjacent streams on the American River north of Nome. Approximately 9 miles of stream placer. Access is from the end of the Kougerok Road then along established trail for approximately 25 miles. 4,000' runway at end of Kougerok Road. Historic Bucket Line Dredge (Walter Johnson) on Windy Creek. (1914 intermittently until 1929). Estimated 85%of valleys are virgin. All claims are shallow (running 3 - 12 ft. to bedrock) Some areas of permafrost because of 2-4 of overburden. No timber on claims. Plenty of Water to work. No anadromous streams. Some ground worked by hand during the gold rush. An exploration program conducted in 2018 with a small backhoe found samples to 0.1 oz/yd. and average of all tests from top of gravel down averaged 0.03/yd. Most tests did not reach bedrock and only a few claims were tested. Sale or lease to qualified Placer Miner. All claims sold as a group. Call or e-mail for more information. Jim Hansen eaglejim39@yahoo.com 907-707-1090 or 907-304-1756 American Creek / Game Creek - Added 2/10/2020. Seventy miles north of Nome, six State of Alaska 40 acre claims next to old Massey dredge American Queen. Main cabin, tool shed, 2x old bunk houses, water pipe about 35 yards from the main cabin. There is quite a bit of equipment and some fuel on site. Previous owner 4-wheeled in from Salmon Lake parking. There is another route that the old tractor trail/railroad used. 2x Landing strips near claims. Military family now unable to work claims due to family situation. https://drive.google.com/open?id=1at0JMLXd3A3twCGiT-hl9-uFx1LtA10V For Sale $50,000 OBO. Please call or email for more information: Sonny 907-406-5122 outlaw13a@gmail.com Porcupine Creek - Updated 2/26/20. PARTNER FOR JV IN 2,700 ACRE gold mining claims in South Central Alaska located N. of Glennallen in a Porphyry Belt and Critical Minerals Belt. Airborne Surveys are done. Documents on request. Partner may do due diligence and after drilling can earn up to 80% interest in the claims. Email turmacmact@msn.com or call Cell: (520)709-0601 Porcupine Creek Information - click or double-click for larger view Valdez Mining District - Added 5/15/19. Roosevelt Lake Area 13 claims for 1720 Acres. Active mining adjacent to claims. Several test runs through a high banker show $20 to $30 a yard. Mostly virgin ground. Windy Creek Canyon, a few miles to the South. 13 claims for 640 acres. I have found gold and silver in good quantities. $15 to $40 a yard on tests. All virgin ground. The claims can be driven to in the summer. 4wd preferred, but not necessary. Prefer to be sold as blocks, but individual claim sales may be negotiated. Contact Claude at 907-394-2552 or email at akclaude2009@yahoo.com Petersville Area - Added 5/15/19. Four forty acre claims located near Poorman and Cottonwood creeks. Road access. Two creeks drain into Cottonwood. Have info of area and geologist report. Asking 150K motivated to sell, serious inquires only. Contact Michele Stevens 907-345-9655 or email: goldengirl@petersvillemining.com website: http://www.petersvillemining.com Thank you for looking. Valdez Mining District - Added 5/15/19. Roosevelt Lake Area 13 claims for 1720 Acres. Active mining adjacent to claims. Several test runs through a high banker show $20 to $30 a yard. Mostly virgin ground. Windy Creek Canyon, a few miles to the South. 13 claims for 640 acres. I have found gold and silver in good quantities. $15 to $40 a yard on tests. All virgin ground. The claims can be driven to in the summer. 4wd preferred, but not necessary. Prefer to be sold as blocks, but individual claim sales may be negotiated. Contact Claude at 907-394-2552 or email at akclaude2009@yahoo.com Petersville Area - Updated 5/15/19. Six State of Alaska mining leases totaling 2,690 acres. State of Alaska Mining Leases are a 20-year lease with the State of Alaska which I own the lease and the lease has 14 years remaining and are renewable. Also available are 25 forty-acre claims with 6 buildings and 3 airstrips. Located in historic and present Petersville/Yentna Mining District area, that has seasonal road access to all claims and leases. Located in Talkeetna C-2 Quadrangle north of the Peters Hills and all above tree line on Cottonwood, Poorman, Pass, Willow, Little Writer, and Peters Creeks where very limited mining of present alluvium has occurred. Drill logs, sampling, and certified geophysical information are available. Owner would like to see the property brought to commercial production. Prices have been dropped and owner is motivated to sell. Leases can be subdivided and sold as smaller leases if need be. Serious inquiries only. For more information contact Michele Stevens @ 907-345-9655, website: http://www.petersvillemining.com or email: goldengirl@petersvillemining.com Thank you for looking. Valdez Creek - Added 4/24/19. I have 40 acres in the upper Valdez creek valley near Tenas lake. Active mining on both sides of claim. $35,000 obo. I also have 600 plus acres on Gold creek across the hwy from Valdez creek. Shallow bedrock. Surrounding area claimed by large mining corp. Easy atv access but last few miles of road need repaired to drive a pickup in. Very good potential for commercial mining. I need to sell it. Only $50,000. I also own 240 acres of hard rock claims on top of Gold Hill. Make me an offer on it. Call 907-768-1137 I am gone often so leave message and I'll call ya back. Manley Hot Springs - Added 2/23/19. Alaska placer mine for sale 50 state claims located on Little Boulder Creek, Salt Creek, Trail Creek and West Fork 30 miles from Manley Hot Springs, AK on Tofty Road. Can access claims by road some older equipment and camp. 83 yrs young time to sell . email miningwild@gmail.com Fortymile River - Added 1/24/19. Fortymile River mining lease for sale. Includes 10 claims, campsite with 2 storage sheds, an 8” & 6” suction dredge, 22’ riverboat for springtime hauling gear and a new 1652 Lund jon boat located 17 miles down river from the lower bridge. Fortymile River Mining Lease area Rental fees to state are only 375.00 a year for all 10 claims since it is a lease. ADL 588388 asking 40,000.00 obo. Call Royce at 907-317-0335 Fortymile River - Added 9/30/18. I have nine claims I want to sell for $3000.00 each. Also have a brand new Keene 8 inch suction dredge, and a new 6 inch dredge. A full camp site with everything you need from tents to wood burning stoves, showers, gold pans, etc. Call and make me an offer I can't refuse for the whole package together, or may sell separate. 941-416-8839. Don. Fortymile River - Added 6/12/18. North fork of the Fortymile River, there are 8 river bottom gold claims for sale at $2500.00 each. Want to sell together if possible. Fortymile claims, camp, and equipment Approx. 9 miles upriver from the North fork bridge. Accessible by boat or hovercraft. Gold average size is 20 mesh with a couple of pickers each day. Average 2-3 grams of gold per hour with a 6" dredge. Gravel bar avg. 2-1/2' of overburden down to bedrock to over on the river channel side is bedrock outcropping. Call 907-227-3850 or lowrielp@aol.com Babe & Vault Creek - Updated 9/30/18. For Lease. We have 440 acres containing almost 2 miles of virgin permafrost placer ground for lease 13 miles N. of Fairbanks. Babe and upper Vault Creek drain a gold rich belt that extends from Ester Dome NE to the Ft. Knox mine. Lower Vault Creek was extensively drift mined in the early 1900’s and was a major producer. One small drift operation was located on Babe Ck. but no production records have been found. There are several old prospect shafts on both creeks that indicate gold values at a MINIMUM of 1oz/30 yds of gravel. One such shaft was cleaned out and taken to bed rock which was at roughly 65’. I recently put down a 6’x6’ shaft and hit bed rock at 60’. Pay gravel is approximately 10’ in thickness. This mining season I’ll be cross drifting the valley to better determine the values to expect both up and downstream. Any operation undertaking the mining of these claims needs to not be deterred by significant overburden which varies from at least 30’ to 70’. An extensive drilling program would be needed. The history of lower Vault shows 1/3 of the gold recovered was 1 penny weight or better. There is good indication that the width of the pay could easily be 150’ to 200’ with the richest pay streaks being around 50’. The two creeks combined typically run enough water to supply a washing operation especially if ponded. There is a large spring that adds significantly to the water available. Contact: Kurt Blumberg e-mail: flintgd@aol.com or phone: 303-507-9502 for additional information. ads by Google... Platinum, AK - Updated 10/2/18. We have approximate 2000 offshore acres of State of Alaska mining claims available. Research: USGS, USBM and Thomas Oommen PhD. Geologist completed 2 studies, one in 2006 and one in 2008. Goodnews Mining Co. recovered 650,000 ounces in a 41 year time frame with a dragline and a bucket line dredge within a 6.5 mile stretch of the Salmon River. We are offering six (6) - 40 acre claims and eleven (11) - 160 acre claims, which total 2000 acres of State of Alaska offshore mining claims. Asking $15,000 US dollars per 40 acre claim, $50,000 US dollars per 160 acre claim, OR $250,000 US dollars for all claims listed above. Please reply to this ad via email at GoldenMooseMining@gmail.com Placer Gold in Alaska - Updated 10/1/18. On five miles of river claims. Gold grades average of 18 large samples is $44 per cubic yard at the grass roots, huge volume of gravel. Airstrip, trails, professionally surveyed and sampled claims with mineral report. Historic mining, but 99% unmined. Adequate water, water rights and cabin included. Complete buyout preferred. Asking $2,500,000. Contact: Jim Halloran augeojim@yahoo.com Valdez Creek / Grogg Creek - Added 1/21/18. Selling 720 acres / 18 claims (40-acre claims) of state of Alaska placer mining claims. Along the east bank of the Susitna River, the claims are located on Valdez Creek. Creek is a historic gold bearing location and a leading producer. All the claims are state of Alaska claims, they are not patented. In the 80’s Valdez Creek (Cambior) became the largest placer gold operation in North America for about 10 years and in the best year it produced over 100,000 ounces of raw gold. The claims are about 212 miles from Anchorage at the confluence of Grogg Creek and Valdez Creek, in the Talkeetna Mining District. The area is reached by vehicles via the Denali Highway which connects Paxson on the east with Cantwell on the west. At about Mile 79 (measured from Cantwell) a gravel road heads north along the east bank Susitna River and goes through the old mining camp of Denali and up in back of White Creek and on the confluence of Valdez Creek and Grogg Creek. 4 miles up from Cambior Mine. You can drive to the claims with a 4x4 or 4-wheeler in the summer. Valdez Creek claims and gold These claims have huge potential. No mining equipment on site. Placer gold exploration permits. Great area for hunting caribou, sheep, wolf and fox. (Mile 69 Denali Hwy) At $450/oz. gold samples assay up to $15.00 a yard. (Reference sample, 1885, Mike Balen / Jerry Hannio U.S. Bureau of Mines). Excellent ore values. 0.0369 fine ounces per cubic yard of fine grained and flakey gold. Ft Knox ADL No. 539731 Downstream Cambior company’s, A channel, was a 15-foot-thick pay stream that ran 10 ounces per cubic yard. Asking $200,000 - the claims will not be sold separately. Contact Peter if interested or with questions. Email: indigoenterprises@gmail.com Call: 206-501-6379 Falls Creek - Updated 10/1/18. I have three claims for sale in the Cache Creek Basin (Dutch Hills). They are on upper Falls Creek. I have held them since the late nineties. I am getting a little long in the tooth now and hope someone will be interested! The asking price is $12,500 for one, $10,000 each for two ($20,000 for two) and a great deal, $9000 each for three ($27,000 for three). Please e-mail me with questions / or interest Niallix@aol.com with the word CLAIM in the subject line. Kougarok River - Updated 10/1/18. Seward Peninsula, approximately 100 miles North of Nome. 8.5 miles of continuous Alaskan State claims on the Kougarok river. 36 forty acre claims, all claims have the river running through them with several very interesting benches . We've prospected these claims over the last 8 seasons using a suction dredge w/ several paystreaks located (98% virgin to suction dredging). Three cabins on the downstream claim (2 miles from end of road), remote ( claims start at 2 miles from end of road and extend upstream for 8.5 miles), ATV, cat trail access. Kougarok River claims We found quite a bit of coarse gold on the lower claims, up to 7 oz nugget with gold running up into the bench from the river. This bench is roughly 35 acres and has an old timers cabin on it which I think they only built a cabin to mine rich ground. The upper claims have a paystreak of smaller gold that extends for at least a couple of miles (we haven't fully determined just how far this extends but have got as high as 2ozs/6 hr dredging session). There is an old cabin that could be fixed up or moved closer to the claims in the upper area. Downstream from there about 3 miles there's a large bench and a terrific campsite on the river. The bench carries colors and heavies (looks to me like an ancient channel). On the lower claims we found a nugget paystreak that probably extends 300' or more (we've established the upper end of this paystreak, then 200' down stream is where we found the 7oz nugget and at that time we covered the downstream ground with tailings so we know that the paystreak extends downstream, possibly for several hundred yards. All the claims are Alaskan State claims which means less problems... no BLM & the Kougarok river doesn't have salmon. Our Bottom line for the whole group of claims is 60K or we could break up the claims and if so we'd ask 60K (bottom 10 claims), and the other 26 claims starting at $2500/claim respectively...the top 6 claims w/ the established paystreak I'd ask $22,000 if sold separately. If you purchased the whole 36 claims the price is roughly $1600/claim (which is a very good deal for I see several 40 acre claims in the general area for 40K or more per claim). I can't over emphasis the fact that we've prospected up there for the last 8 seasons...we know where we didn't hit any gold...we know where we hit some gold but not enough to pay with our 6" dredge... we know where there are existing paystreaks.... we know hidden trails for access.... we know of 4 separate benches that we've panned gold on.....and can give advice as to camping etc ... all this information is very valuable and should be taken into consideration. (most of the claims I see advertised don't have much positive information available). GPS coordinates : downstream boundary is 65.4589N, 164.6878W and upstream extends to 65.5671N, 164.7390W....ADL # 554358 thru 554390 plus 705584 and two other claims .... Fineness of the gold is 90.5 to 91%.......Age forces sale.....Contact: Jim at 530 626 8753 (10am to 5pm Mon thru Sat) or Jan at 360 427 5367 ..... email jansiks@yahoo.com Kenai Gold Claims - Updated 10/1/18. Fifteen 40-acre state claims in two groups of placer ground with great access and off the road parking. All the claims would be great for suction dredging and high banking. Some of the claims have enough low bench ground for heavy equipment operations. They have not ever been mined to any significant degree. They have been held for decades in speculation, but they have a mining history. Hope-Sunrise Mining District. Good gold on every claim. No equipment and no permafrost. Thirteen thousand dollars per claim or a better rate on groups of claims. Sold in two or more claim groups only. About 70 highway miles from Anchorage. Contact: augeojim@yahoo.com for more information.
  3. 1 point
    This is my latest "Nugget Detector Guide", now published for over fifteen years, updated May 2020 with some of the latest model information. Each model has a short description, followed by a very PERSONAL OPINION. Copyright 2002-2020 Herschbach Enterprises - Please do not reuse or repost without my express permission. This is offered as a simple guide for those wanting a general comparison of the various nugget detectors available new with warranty, along with some kind of real opinion about them. That's all it is, folks, so take it or leave it for what it is worth. It's just that listing specs is of little help to people, and so I take my best stab at providing some guidance for those newer to detecting. These are only my opinions based on my experience with various detectors over the years. While I do have a lot of experience, I must throw in the caveat that I have not used all detectors under all conditions. What may be considered a good detector at one location may not be so good at another location due to differences in ground mineralization and the gold itself. Detector performance is site specific and so your mileage may vary. Never forget that when reading comparisons on the internet. Although many detectors sold today can potentially find gold nuggets, I've chosen to only list current models from major manufacturers that are sold and marketed primarily as prospecting detectors or that at least have a specific prospecting mode. I no longer list general purpose VLF detectors running under 18 khz because they are just too common and that being the case they offer nothing special to the potential gold prospector. If you are interested in other general purpose detectors that might make good prospecting machine but are not listed here, look at my more comprehensive reviews list. Many discontinued prospecting detectors are also listed there. The list below has over twenty models listed and still may be too much for some people. In recognition of this I have made my best shot at picking three possible options I am calling Steve's Picks. Click the link to jump there at the end of this page. Various popular VLF gold nugget prospecting metal detectors Please, if you own one of these detectors, and I call it like I see it, don't take offense. Any nugget detector made will find gold in capable hands, and the owner is far more important than the detector model. I'll put a good operator with almost any detector on this list up against a novice with whatever is deemed "best" and bet on the experienced operator every time. The person using the detector finds the gold. The detector is actually one of the less important factors in nugget detecting success or failure. A quick note to those who know nothing about these machines. These are metal detectors. There is no such thing as a "gold only" detector. These detectors will also find lead, copper, aluminum, and other metals. These units are best used to look for relatively larger pieces of gold at relatively shallow depths. Concentrations of gold dust are not detectable. Some of these units can hit gold that weighs as little as a grain (480 grains per ounce) or less but only at an inch or two. Only the larger nuggets can be found at depths exceeding a foot. Only world class nuggets weighing many ounces can be detected at over two feet. The vast majority of nuggets found are found at inches, not feet. About Long Range Locators (LRLs) WARNING ON COUNTERFEIT DETECTORS - The market for nugget detectors far outsells coin and relic detectors worldwide, with huge sales in third world countries. This has made many of the models below very popular with counterfeiters. Here are some Fisher and Minelab examples. If you shop these models there are two simple rules. First, you are safe if you stick with approved dealers. Second, if the price seems too good to be true, beware! All legitimate dealers have a limit on how low they can advertise, the Minimum Advertised Price (MAP). Review prices at the approved dealer list, and if you find the detector advertised as new at a significantly lower price by somebody not on the list, the odds are very high you are looking at a counterfeit detector. Legitimate dealers are prohibited from advertising at those kind of prices, and a price too good to be true is your number one warning you are about to be ripped off. The detectors are listed in order based on the lowest price normally advertised on the internet as of the date below. Steve's Guide to Gold Nugget Detectors - Updated May 2020 Fisher F19 ($449, 19 kHz) - This detector is a later, more advanced version of the Fisher Gold Bug Pro (see below), with added features. There is an excellent threshold based all metal mode plus a dual tone discrimination mode. The F19 has both ground grab and manual ground balance, plus adjustable tone break, just like the Gold Bug Pro. Extra features are added to enhance the coin, relic, and jewelry capability, such as notch discrimination with adjustable notch width, volume control, separate ferrous tone volume, and a LCD meter backlight. These extra features may even find use while gold prospecting. The Fisher F19 can use any Gold Bug compatible coils plus those made for the Teknetics G2 series, providing for a huge number of possible accessory coils. This detector can be had with several stock coil options, including a 7" x 11" DD coil, or 5" x 10" DD coil. Weight including a single 9V battery is 2.6 lbs Steve's Opinion - First Texas, the manufacturer of Bounty Hunter, Fisher, and Teknetics metal detectors, sells quite a few identical or near identical metal detectors under different brand names and model names. Due to oddities in their marketing scheme, some more powerful models are often available at lower prices than other less capable models. Currently the 19 kHz Gold Bug name carries a premium price, while other identical or more capable models sold under other names can often be had for less money. That is currently the case with the 19 kHz Fisher F19 models and the identical Bounty Hunter Time Ranger Pro model. The bottom line is this. If you can find a Fisher F19 with 5" x 10" elliptical coil for under $500 at a legitimate dealer (see counterfeit note above) it is easily my current recommendation for an extremely capable entry level VLF nugget detector with general purpose capabilities. I recommend this detector over the Fisher Gold Bug and Gold Bug Pro models below, not only because of the extra capability, but because it can be had stock with the 5" x 10" DD coil, the best general nugget hunting coil for the FT 19 kHz series. It can only be had as an accessory coil on the Gold Bug models, driving their out of pocket cost even higher. A Steve's Pick. If you want a real deluxe set of extra coin and jewelry detecting features, see the equally capable Minelab X-Terra 705 below for only $50 more. Fisher Gold Bug ($449, 19 kHz) - Not to be confused with the Gold Bug from the 1980's, this new model runs hotter than that old model, and offers full LCD target identification. The target ID makes the Gold Bug good for more than just nugget hunting, and it finds favor also with jewelry and relic hunters. This model normally comes with a 5" round DD coil to enhance the sensitivity to small gold but other stock coil options are available. The Gold Bug features an easy to use ground balance "Grab" function. Do not confuse this detector with the Gold Bug Pro (see below), a nearly identical detector that adds a manual ground balance control.Weight including a single 9V battery is 2.5 lbs. Many accessory coils are available for the Gold Bug. Steve's Opinion - It used to be that this basic 19 kHz model was desirable for it's low price. Now, you can get the Fisher F19 above with a better coil and far more capability for the same price. Pass. Minelab X-Terra 705 Gold ($499, 3, 7.5, 18.75 kHz) – This detector has a unique design feature. The standard unit comes with a 5" x 10" DD 18.75 kHz coil. Accessory coils are available not only at 18.75 kHz, but also at 3 kHz and 7.55 kHz. You can literally change the frequency of the detector by changing the coil! The X-Terra 705 has a large number of features and operating modes making it suitable for almost any type of metal detecting, be it for coins, jewelry, relics, or gold nuggets. Weight including four AA batteries 2.9 lbs. Over ten accessory coils are available for the X-Terra 705 (Minelab, Coiltek). Steve's Opinion - I like the X-Terra 705 very much indeed. It has a very powerful all-metal Prospecting Mode. The X-Terra 705 offers both ground tracking and manual ground balance; I like having both options. I particularly like its very compact and lightweight design. What really sets the X-Terra 705 apart however is all its other features. The X-Terra 705 is a good choice for somebody who wants all the coin and jewelry detecting options important to urban detectorists. It has discrimination and tone options equaling far more expensive detectors. This is the machine for somebody who really wants all the features a top end detector offers and still have a good prospecting detector. 2020 Note - a new lower internet price of $499 (down from $699) makes this detector an alternative to the Fisher F19 above. For $50 more the X-Terra adds quite a few extra bells and whistles for the coin, jewelry, and relic hunter, especially in the realm of target tone id options. It is likely this detector will be discontinued by Minelab when current stocks run low, replaced by the new Vanquish coin detectors. Nokta/Makro Gold Racer ($509, 56 kHz) - The Gold Racer is based on the original Racer model released in February 2015. The Gold Racer at 56 kHz was unique when released in having all the features normally associated with coin and relic detectors yet it's running at a very high nugget detecting frequency. This makes it more of a general purpose detector than a dedicated nugget detector. The Gold Racer comes with a 10" x 5" DD coil and has three accessory coil options. The weight including four AA batteries is 3.0 lbs. Steve's Opinion - I like the Nokta/Makro Gold Racer as it really is something new instead of just another mid-frequency do-it-all detector. The compact lightweight design appeals to me as does the high frequency sensitivity to small gold nuggets. It is the only machine in it's class that can run a large (15" x 13.5" DD) high frequency coil and as well as having a concentric coil option. Best of all it offers a full range of discrimination features not seen in other high frequency nugget detectors, all at a very aggressive price. Worth a very close look, especially if a large coil option is important. Fisher Gold Bug Pro ($549, 19 kHz) - Essentially the same as the Gold Bug above with the addition of manual ground balance. The target ID makes the Gold Bug Pro good for more than just nugget hunting, and it will find favor with jewelry and relic hunters. The manual ground balance gives expert operators the control they desire to get the best depth possible. This unit normally comes with a 5" round DD coil to enhance the sensitivity to small gold but other standard coil packages are available. Weight including a single 9V battery is 2.5 lbs. Many accessory coils are available for the Gold Bug Pro. Steve's Opinion - The Pro is the final version in this series which saw several early variations including the Gold Bug above. It is a excellent choice for prospecting, relic, or jewelry detecting and does fine as a coin detector also. However, you are now paying a premium for the Gold Bug name, and the more capable Fisher F19 at the top of this list can be had in a better configuration at a lower price. Unless you just want the name, pass. Nokta/Makro Gold Kruzer ($636, 61 kHz) - Nokta/Makro started shipping the new Gold Kruzer model in June 2018. The Nokta/Makro Gold Kruzer is a variant of the Nokta/Makro Gold Racer above that has been boosted to 61 kHz from 56 kHz and put in a waterproof housing good to 5 meters (16.4 ft). The Gold Kruzer comes with a 10" x 5" concentric coil and a 4" x 7.5" DD coil. The weight including LiPo batteries is 3.0 lbs. There are four coils available for the Gold Kruzer. Steve's Opinion - The Nokta/Makro Gold Racer has been one of my favorite detectors because until recently there was nothing running in this frequency class that had full target id and other options normally seen only in coin detectors. The Gold Kruzer takes it all to the next step by being waterproof in excess of ten feet. There are no other detectors running at a frequency this high that are fully submersible with built in wireless capability and therefore this detector may find favor with freshwater jewelry hunters as well as prospectors. The Gold Kruzer is worth keeping an eye on and is a better value than it appears at first glance due to the dual coil packaging. Note 2020: the Nokta/Makro Gold Kruzer package has been reduced from $749 to $636, dropping it just under the AT Gold in price. This aggressive price drop in a waterproof 61 kHz dual coil package makes this model very hard to resist. I would not even consider a Garrett AT Gold personally compared to the Gold Kruzer at this price. Garrett AT Gold ($638, 18 kHz) - A totally new concept in metal detecting from Garrett Electronics. This full featured detector has everything you would expect from a dry land detector - LCD display, full control set and functions, speaker, interchangeable coils, and light weight. But it is submersible to 10 feet! Even the speaker is waterproof. Note that the unit itself may be submerged but if you want to put your head underwater you will need optional submersible headphones. Weight including a four AA batteries is 3 lbs. The stock coil is a 5" x 8" DD elliptical. Many accessory coils are available for the AT Gold. Steve's Opinion - The Garrett AT Gold was an innovative option when it was introduced, and the only waterproof nugget detector option at the time. The industry has caught up and even surpassed Garrett now and unless the AT Gold comes down in price it's hard to recommend for somebody interested primarily in a nugget detecting VLF. Only for Garrett fans really, otherwise newer models like the Nokta/Makro Gold Kruzer above are better deals. ads by Amazon... Minelab SDC 2300 ($3799, Pulse) - This model is unique as Minelabs first waterproof pulse induction metal detector. A key feature is that the detector is physically packaged in the proven F3 Compact military housing that is waterproof to ten feet and folds down into an incredibly compact package only 15.7" long and weighing 5.7 pounds including four C cell batteries. Steve's Opinion - I have used the Minelab SDC 2300 for a over a year now and I must say I am very impressed. The waterproof compact design is perfect for hardcore backpack style prospecting. The main thing however is that the SDC 2300 comes as close to VLF type performance on small gold as you can get while being almost impervious to the ground mineralization and hot rock issues that plague said VLF detectors. In fact, the SDC 2300 will find gold nuggets smaller than most good VLF detectors can detect even under favorable conditions. The SDC 2300 is also one of the simplest detectors to use and master on the market. The main caveat is that the detector is optimized for small gold with the hardwired coil and so other ground balancing PI detectors are a better option for large nuggets at depth. It is also nearly twice the price of the Garrett ATX above and so you are paying quite a premium for a little better performance on small gold. Still, for novices in hot ground that can afford the price, the SDC 2300 is almost impossible to beat if the goal is just to go find some gold, any gold at all. Minelab GPX 5000 ($3999, Pulse) - This Pulse Induction (PI) unit essentially ignores ground mineralization and most hot rocks. The GPX 5000 is designed specifically for nugget detecting and so it has many adjustments for mineralized ground not available on other PI detectors. The GPX 5000 is the culmination of over 10 years of innovation in pulse induction technology. The GPX weighs 5.3 lbs. not including the harness mounted battery, which weighs another 1.7 lbs. The detector comes with both an 11" round mono coil and 11" round DD coil. Over 100 accessory coils are available for the GPX 5000 (Minelab, Coiltek, Nugget Finder)! And more coils are being released every year. Steve's Opinion - It is simple. The Minelab GPX 5000 is the safe choice for best all around pulse induction gold prospecting performance. It has been out for many years, is well proven and reliable, and has a vast selection of coils and accessories to cover almost any situation. Despite the new GPZ 7000 below this is still the unit most people should be looking at though the even lower price GPX 4500 above should also be considered. A Steve's Pick. Minelab GPZ 7000 ($7999, ZVT) - The new Zero Voltage Transmission technology from Minelab promises to take gold prospecting to the next level. The new platform represents a break from the past SD/GP/GPX series in more ways than one, with a new weatherproof housing design based on the Minelab CTX 3030. The GPZ 7000 weighs 7.32 lbs. and comes with a waterproof 14" x 13" coil. There is one accessory coil available at this time. Steve's Opinion - The GPZ 7000 represents the future and I am convinced it offers a performance edge when compared to the earlier Minelab PI detectors. For this reason I have sold my GPX 5000 and switched fully to the GPZ 7000. The only weakness the machine seems to have at this time is an inability to deal quietly with wet saturated salt or alkali ground and certain volcanic hot rocks. That said I have not regretted for one second selling my GPX 5000 due to the overall advantage I feel I get with the GPZ 7000 in my ground and on my gold. If I can offer one final word of advice, it would be to pay particular attention to what experienced nugget hunters are using in any particular region. Do not assume you are going to outsmart them and find some model they have not already tried and set aside as less than optimum. Serious prospectors in any particular location will end up focusing on certain units that do the job. In areas of extreme mineralization this is usually a PI detector. In areas with less mineralization and lots of ferrous trash VLF units often are preferred. If you can discover what models the locals prefer it will give you a head start in knowing what to use yourself. Above all, whatever detector you finally choose, dedicate yourself to mastering it. It takes at least 100 hours of detecting to become proficient with a detector model. Any less, and you are still practicing. Knowing your detector well is more important than what particular model of nugget detector you own. Steve's Picks I decided to add something new to this page. The list above has grown so much over the years that even it is really too long for some people. So I have decided to just pick my favorites in the three essential categories that I think every new prospector should consider: 1. The super hot VLF 2. The medium frequency VLF 3. The ground balancing pulse induction (GBPI). The explanation that follows gives some rationale for my picks, but a huge factor is a good proven history in the field by many people under a wide range of conditions. Just being the latest new thing does not do it for me as much as being tried and true when it comes to my recommendations for others. It is very wise to wait about 6 months to a year after any new detector is introduced to see how others fare with it in the field before committing your hard won dollars. Widespread dealer support and service options are also very important. Finally, and this is most important. This short list is aimed at beginners. I assume the more knowledgeable folks don't need this kind of guidance. I am specifically assuming the reader is a first time buyer looking for the best value in a proven nugget detector. Along with that I lean towards simplicity of operation and focus on the task at hand as opposed to overwhelming control options. So these machines are not a list of the three "best" machines but instead a list of what I think are solid options I would advise a person new to nugget detecting to consider. Category one is the hot induction balance detector for finding tiny gold nuggets no other detector can find. These would be detectors running over 30 kHz. Contenders are the Fisher Gold Bug 2 at 71 kHz, Makro Gold Racer at 56 kHz, Makro Gold Kruzer at 61 kHz, Minelab Gold Monster at 45 kHz, and White's GMT and Goldmaster 24K at 48 kHz. This is a tough one because so many of these detectors get the job done so well. My pick at this time is the new White's Goldmaster 24K. This new detector is easy for beginners but has room to grow with features professionals will appreciate, good ergonomics, and a great coil selection. I have one myself, so there you go. Category two is the medium frequency VLF. The main goal here is to have a detector that can punch deeper on large nuggets in bad ground than the super hot VLF detectors and do a good job of discriminating out ferrous trash. These would be the good detectors for working trashy campsites and tailing piles. They are also the detector for a person wanting more versatility for other detecting tasks than offered by the dedicated high frequency detectors. The potential contenders list is very long - see above. My pick at this point in time is the Fisher F19, a more capable Gold Bug Pro variant available stock with the 5" x 10" DD coil, and at a lower price now than the Gold Bugs, which carry a higher price simple due to the name. An excellent alternative for those wanting a truly deluxe do-it-all machine with all the bells and whistles is the Minelab X-Terra 705 for just $50 more. Category three is a detector to handle the worst hot rocks and bad ground. For many serious prospectors this will be the primary unit, the one to find gold with. The obvious choice here (for me anyway) is a Minelab GPX 5000. This detector is the culmination of years of development by Minelab and it has incredible aftermarket support in the form of coils and other accessories. For those with the money and a desire to be on the cutting edge of new technology the Minelab GPZ 7000 is an alternative but the GPX 5000 is a safer choice for a wider range of conditions. Those who want a GPX 5000 and who can't quite afford it should instead consider the GPX 4500 at half the price. If a GPX is too intimidating, then the Minelab SDC 2300 may be just the ticket. Steve's Short List of The Prospecting Metal Detectors May 2020 1. White's Goldmaster 24K (category 1, small gold sniper) 2. Fisher F19 (category 2, basic general purpose prospecting) 3. Minelab GPX 5000 (category 3, ground balancing pulse induction) In my opinion a well equipped prospector needs two detectors. One a high power GBPI for most nugget detecting and a VLF for trashy areas and as a backup. A GPX 5000 plus a F19 or Goldmaster 24K would be a hard combination to beat. A special note of the Minelab GPZ 7000. This detector represents a fourth category, the "hybrid" detector that uses continuous wave technology like a VLF but also employing time constants much like a PI detector. These detectors act like a "Super VLF" with the ability to detect gold missed by GBPI detectors but with the ability to get depths on par or exceeding those previously seen only with GBPI detectors. I hesitate recommending it over the GPX 5000 to just anyone because of the high price tag, weight, and lack of coil options. The GPX 5000 in my opinion is the safer choice for overall versatility, at half the price. So there you are. Hopefully this helps some people out. I can be found daily on the Detector Prospector Forums and would be pleased to answer any questions you have on metal detecting and prospecting. Also check out Steve's Guide to Metal Detecting for Gold Nuggets. Sincerely, ~ Steve Herschbach Steve's Mining Journal Copyright © 2002 - 2020 Herschbach Enterprises - Please do not reuse or repost without my express permission.
  4. 1 point
    The White's PulseScan TDI was released in 2008 and is still in production as the TDI SL. Prior versions have been discontinued. I was one of the original users of the TDI and still dabble with them to this day. See my story White's TDI at Moore Creek, Alaska for pictures of lots of TDI gold nugget finds. I also have extensive notes on using the TDI for coin detecting at Steve's Guide to White's TDI Coin Settings. The TDI is a unique detector and is seeing use in many applications unforeseen when it first came out. The TDI has been available in several versions but all are basically the same detector as far as how they work. October 2019 Note: White's has a model called the TDI Hi-Q, which is a TDI SL with straight rod, new coil, and tan or camo paint job. See the details here. I am a big fan of competition as I always want more and better detectors from the manufacturers personally, and I think competition is the best way to get better detectors. After Garrett got into the ground balancing pulse induction (GBPI) game with the Infinium people including myself were really after White's to make an entry into the field. I went so far as to visit White's Electronics personally to lobby for such a detector with suggestions on how to get there. In particular, I advised that rather than developing something from scratch, it might make more sense to license the existing Goldscan technology from Eric Foster, widely known as "the father of pulse technology" for his early work in the field. Eventually White's did decide to pursue the matter, and I was therefore aware early on that White's was working on a new detector, In 2007 I was sent a prototype unit to evaluate while I was on vacation in Hawaii. I was very impressed not only with the power of the detector but more importantly for me in Hawaii I was very impressed with how stable the detector was in salt water. It was also virtually immune to electromagnetic interference (EMI) issues that had dogged my use of other detectors in Hawaii. White's TDI SL with closeup of control panel (compare to original TDI controls below) My use of previous GBPI detectors, the Minelab models and the Garrett Infinium, made me familiar with how they respond to targets with various tones. Each target generates a dual tone that varies depending on whether the target is above or below the ground balance point that has been set. You will hear either a high tone followed immediately by a low tone (hi-lo), or a low tone followed immediately by a high tone (lo-hi). This dual tone system is effective for most uses but if you get into a target rich location it in effect doubles the number of audio signals coming from the detector. I also had an opportunity in Alaska to visit with Brent Weaver, the main engineer at Garrett responsible for the development of the Infinium. While testing a prototype Infinium I asked him about the dual tones (Garrett now refers to them as "echos") and whether they could be suppressed. He told me the dual tones were integral in how the Infinium worked and that it was not practical to produce a single tone result on the circuit they were working with. White's did end up working with Eric Foster on the development of the TDI. His method is one I like because instead of the dual tone responses generated by the Minelab and Garrett models (hi-lo or lo-hi) the TDI generates one of two tones, either a low tone, or a high tone. The tone depends on whether the target is above or below the current ground balance setting, and therefore there is only a tone difference when the ground balance system is engaged. The ground balance off, straight PI mode has monotone responses. Also, because the ground balance can be set manually on the TDI, this tone "breakpoint" can be shifted by the operator. This allows targets to be separated broadly into two distinct groups. On one hand there are high conductor type targets, like most coins and large steel items, that on the TDI produce a low tone response. The other group is comprised of low conductor type targets, and includes most gold items, US nickels, aluminum, and small ferrous trash. These all produce a high tone response on the TDI. There are far more high tone targets than low tone targets in most locations. I really liked the prototype TDI that I used in Hawaii, in particular the fact that it generated half the audio responses compared to a Garrett or a Minelab. Once again I wondered if one tone or the other could be suppressed. I sent an email to Eric Foster, and was surprised when he told me that not only could it be done, but it would be a very simple thing to implement with a basic toggle switch arrangement. This came about very late in the TDI development, and I lobbied hard for just such a feature to be added. A last second vote was taken by those involved, and probably the last major change on the TDI before it went into production was the Target Conductivity switch. There was no such switch on the tan prototype models. Prototype White's TDI Used by Steve Herschbach in Hawaii Now, I do not want to give the impression I was some kind of major player in the development of the TDI. I was just one of many voices pushing at White's for years to develop a ground balancing pulse induction (GBPI) detector. I am pretty sure though my last second inquiry and little push was what made the tipping point to getting the Target Conductivity switch included, and I think to this day it is one of the most useful and intriguing features on the TDI. It allows for a vast reduction in the number of audio responses in certain situations and in conjunction with the manual ground balance and pulse delay offers a degree of discrimination on the TDI not seen on any other pulse induction detector made today. This makes the TDI a pulse induction machine that can be used effectively for coin detecting, if the operator knows what they are doing and employs some smarts in site selection. I wrote an article entitled Steve's Guide to White's TDI Coin Settings on this very subject. I will not repeat the information here in the interest of keeping this page from getting too long so check out the link. Suffice it to say the TDI has the ability to play tricks and discern targets far beyond what most PI detectors can achieve. Another major feature on the TDI is the ability for the ground balance system to be shut off. The method used to ground balance the TDI in effect subtracts the ground reading from the total readings returned by the detector. This subtractive method does actually steal some depth, which is easily shown in air tests on targets with the ground balance turned on and the ground balance turned off. The closer the target is in relation to the ground balance setting, the more depth is lost. People find this very confusing, as the whole point of ground balancing a PI is to get better depth, right? Original White's TDI Control Panel The way it works is this. In low mineral ground a PI gets maximum depth without using any ground balancing. However, as mineralization increases, depth is affected. The more mineralization, the more depth is lost. Also, ground effects increase. In low mineral ground, the coil may be raised off the ground with little response. In highly mineralized ground, raising the coil even slightly off the ground produces a false signal. Nearly all PI detectors have an audio retune circuit that slowly retunes the audio response to keep it at the set threshold level. Otherwise circuit drift and minor ground variances would require constant retuning. In high mineral ground, the ground produces a response, but the detector compensates as long as the coil is kept at an exact height over or on the ground. If the coil is raised quickly, the audio overshoots when the ground signal is removed and a false signal occurs. This can be a real problem in even ground or in the water where it is difficult to maintain a steady distance above the ground or sea bottom. Hot rocks or wildly varying ground mineralization present an even greater issue. Again, the detector does well as long as the conditions are constant, but when a hot rock or mineralized ground condition like a clay seam enter the picture, a false signal is heard. In areas with lots of hot rocks PI detectors that cannot ground balance are almost useless due to the overwhelming number of false signals. So imagine a PI with no ground balance in low mineral soil. All is well, maximum depth is achieved. Pretend we have the ability via a magic dial to turn up the ground minerals and/or hot rocks in the ground. A point is reached where performance and efficiency is greatly impacted. It becomes impossible to discern good targets from ground signals and false hot rock signals. At such a point, engaging the ground balance circuit gains back the lost performance and efficiency. It does this by eliminating the ground signal and hot rock signals. White's search coils for TDI (from 2018 product catalog) This leads to situations occurring where people use a GBPI detector in low mineral ground and decide they are no better than a VLF. That actually often is true, in that a good VLF in all metal mode will do about as well as a Ground Balancing PI in low mineral ground, if both have similar coil sizes. A GBPI does not come into its own until the ground conditions or hot rocks are such that a VLF operator wants to toss the detector in a gully in frustration. This has been a very long lead explanation to the TDI secret weapon. In low mineral ground, turn the ground balance off! The detector will become extremely stable with a very smooth threshold and become more resistant to electrical interference. Gain may be boosted and a great deal of extra depth achieved in situations that allow for this type of operation, and they are actually very common. This would be the preferred beach mode on most beaches, the exception being beaches with a lot of black sands. The White's TDI in pure PI mode is one of the most powerful straight PI detectors available. The tone differences between targets disappear, and sometimes the ability to differentiate targets is more important than the depth gained by shutting the ground balance system off. But do not overlook this ability to run without ground balance in situations that warrant doing just that as it can really pay dividends to the knowledgeable operator. In 2018 White's responded to long standing demand from customers and released a version of the TDI that is waterproof to 25 feet - the TDI Beachhunter. This is basically a TDI SL in a Beachhunter ID control box. The model weighs more at 5.2 lbs for obvious reasons. The TDI Beachhunter has all the same controls as the TDI SL with the exception of the conductivity switch. This means the TDI Beachhunter signals on all targets, but the dual tone scheme remains to allow the operator to differentiate targets by the sounds. In order to help insure waterproof integrity the coil on the TDI Beachhunter (12" Dual Field coil) has been hardwired into the control box. Forum thread with more information on TDI Beachhunter. White's Electronics TDI Beachhunter - new for 2018 ~ Steve Herschbach Copyright © 2010 Herschbach Enterprises Official White's TDI SL Page White's TDI SL Data & Reviews White's TDI SL Instruction Manual White's TDI SL Special Edition Data & Reviews White's TDI BeachHunter Data & Reviews White's TDI Pro Instruction Manual White's Original TDI Instruction Manual White's TDI Field Manual Forum Threads Tagged "whites tdi" White's Metal Detector Forum Great Post on Batteries For the TDI SL White's TDI Coin Settings Some Commentary On TDI Tuning & Discrimination White's TDI Technical Specifications* Internet Price TDI SL $1189 (Special Edition $1049) (Beachhunter $1199) Technology Ground Balancing Pulse Induction (GBPI) Frequency 3250 - 3370 Pulses Per Second Autotune Mode(s) Slow Motion Ground Rejection Manual, one turn control Soil Adjust Ground Balance On or Off (two position switch) Discrimination Conductivity switch*, 10 - 25 Pulse Delay Volume Control No Threshold Control One turn control Tone Adjust No Audio Boost No Frequency Offset One turn control Pinpoint Mode No Audio Output Speaker, 1/4" headphone socket Hip Mount No (TDI Beachhunter - Yes) Standard Coil(s) 12" Round Dual Field Optional Search Coils Over 100 accessory coils available (TDI Beachhunter has hardwired coil) Battery Rechargeable NiMH & AA Operating Time Up to 6 hours Weight TDI SL 3.5 pounds ( TDI Beachhunter 5.2 lbs) Additional Technology The TDI was designed specifically to be able to use Minelab SD/GP compatible coils. However, performance can vary and the pulse delay may have to be advanced to compensate for coil differences that result in overload readings. TDI Beachhunter is waterproof to 25 feet. Notes *The TDI is unique in that it can suppress audio responses into two different classes. Targets have a high tone or low tone audio depending on how the target relates to the ground balance setting. In general high conductive targets give a low tone and low conductive targets a high tone. The TDI can be set to allow for one response or the other. See White's TDI Coin Settings for more details on this control. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart. White's TDI SL High-Q Tan metal detector
  5. 1 point
    Well, back home safe and sound after a couple weeks in Hawaii with my wife. We visited the island of Kauai for the umpteenth time. We like the laid back vibe, made even more so by being familiar with everything. We do what we both like - she relaxes in the sun and I go metal detecting. And lots of walks and dinners together. The back story is told at Steve's Mining Journal about prior trips made to the same location over the years. Hawaii has always been a pet project of mine as it is the most difficult environment I have even encountered for a metal detector. There is of course the salt water. There is also literally military grade electromagnetic interference (EMI) from military installations plus missile and satellite tracking stations. Finally, there is a mix of non-magnetic coral sands and volcanic basalt derived sands and cobbles. Throw in the heavy surf and out of control tourists on surf boards trying to kill you... things can get interesting! If you stick to the tan to nearly white sands you can get decent performance from many detectors. But when the basalt gets involved is where things get fun. Most prospectors are familiar with basalt rocks and the challenge they present in gold prospecting. Well, just take the same hot rocks and douse them in really salty water and heavy duty EMI and you have Hawaii. Multi frequency VLF detectors like the Fisher CZ or Minelab Excalibur do ok in in the stuff but lack any real punch. They do best in the whiter sands, but the basalt sands and cobbles really leave them feeling gutless. I went to PI detectors early on, and overall probably had my best results with the various White's Surf PI models. Again, however, they worked best in homogenous materials. Places where the white sands and basalt cobbles mixed gave the Surf PI fits as it hit on the basalt cobbles. In darker sand beaches it was near impossible to keep the machine steady over the bottom in the surf, leading to lots of false signaling. I tried several Garrett Infinium detectors in Hawaii and got tantalizingly close to the detector I wanted. The Infinium as a ground balancing PI could tune out the black sands and hot rocks and eliminate many of the false signals. But it introduced just as many if not more by an inability to play well with salt water and EMI. The interference in particular made the Infinium almost unusable at times. I really wanted a stable Infinium, and confirmed this idea by using the White's TDI in Hawaii. It seemed to solve the issues I was having with the Infinium and so I waited for White's to make a waterproof TDI. And waited. And waited. I waited so long that Garrett had time to take what they learned from the Infinium and another model, the Recon, and build a next generation PI, the Garrett ATX. I was cautiously hopeful that all the noise I had made over the years had been heard, but frankly, I was not getting my hopes up too much. On top of that, the good old days are gone. I used to spend a couple weeks in Hawaii years ago and never see anyone with a detector. This trip I saw people every day! Ok, often the same guy but also more different people detecting than probably all my previous trips combined. The competition has gotten fierce by comparison to the old days. Hawaii treasure of another sort - beautiful beaches lit up at sunset! The Garrett ATX is the best PI detector I have ever used for difficult water hunting. Hands down, no comparison. I have to qualify that by saying that what makes it shine is the severity of the conditions. A person buying it and using it on clean white sands in Florida would probably have a less enthusiastic reaction. There is a lot of confusion regarding ground balancing PI (GBPI) detectors like the Garrett Infinium or White's TDI. They do not air test well against good VLF detectors and indeed do not really perform all that well against them in mild ground. People never really understand what detectors like these are all about until they get into difficult ground. The kind of ground where the best VLF detectors lose half their depth, the GBPI detector just keeps plugging along, and all the sudden now have a big depth advantage. Not because they go so deep to start with, just that VLF detector fare so poorly in really bad ground. GBPI detectors only really shine in the worst conditions. Let that sink in because it is very important. Anyone reading this should not get the idea these detectors are the be all or end all for all circumstances. But when the going gets tough, when other detectors fall on their face, a GBPI detector like the Garrett ATX can be the answer. Tuning a detector like the Garrett ATX can really bother some people. There is this resistance to doing anything that reduces the theoretical max depth of the detector. As soon as you start getting into reducing settings the feeling is that "well, yeah, but now it does not go as deep". The reality is that any machine that can be run maxed out in bad conditions has left some performance on the table. You may be able to max settings in benign ground, but you should have to back off of max settings in really bad conditions. That is why the controls exist - to compensate for bad conditions. The goal is to be set as high as possible while getting stable performance. The ATX is a powerful detector, and so it should be expected the machine has to be dialed back in severe conditions. The ATX has three adjustments that affect the depth. The Gain control is the simplest. You decrease the sensitivity of the detector to help compensate for conditions that are introducing too much noise. Just like the Gain or Sensitivity control on a VLF detector. This control was lacking on the Infinium and is a major reason why the ATX is superior. There is the pulse delay, which Garrett labels as a discrimination control. It is, sort of. Without getting all technical on you it is also a sort of sensitivity control, in that increasing the delay or discrimination also eliminates signals from weak conductor targets like foil, hot rocks, or salt water. This is really the only control you have on the Infinium to deal with false signals and it serves a similar function on the ATX. Finally, you have the ground balance. The ground balance is basically another type of discrimination circuit or filter. The signal produced by the ground is determined and then eliminated. However, this comes at a cost. Items that read the same as the ground signal are also eliminated, and items near to the ground signal will exhibit reduced signals. The White's TDI makes it easy to demonstrate this. You can turn the ground balance completely off, and when you do so the machine air tests far better than it does when you turn the ground balance on. This is because of the subtractive nature of the ground balance circuit on the TDI. Also, because it has a manual ground balance, you can see the effect of tuning the ground balance control closer to and farther from a particular target response. Instead of tuning out the ground the control can be manipulated to tune out other items instead. It is just a basic discrimination circuit. Different ground balance methods can affect items to greater and lesser degrees so the example shown by the TDI should not be taken as being the same with all detectors. But the effect is real and does exist to some degree on all ground balancing detectors, both VLF and PI. So why use ground balance? That should be obvious - to tune out ground responses. If there is no detectable component in the ground you would be better off without the ground balance circuit. Such conditions rarely exist, but they do exist. Absolute pure white coral based sands are one of them. The ATX at its hottest will detect salt water however, and new to the ATX is the ability to ground balance out the salt signal instead of the ground signal, but you are trading some sensitivity for stability doing it. Long round about way to explain that when the Garrett ATX is turned on with factory default settings the ground balance setting is at a minimum. The ATX should be tried first with the factory default setting and on many beaches you will not want to ground balance it. Just leave the discrimination (pulse delay) at zero, set the gain as high as possible while still allowing the machine to be stable, do a frequency scan, and go. In Hawaii at my location however I could not do this. I could on clean sand but not in the cobbles I wanted to hunt. But first, a total surprise. My ATX was almost totally immune to the EMI that I had previously experienced on Kauai without even doing a frequency scan. The frequency scan was basically redundant. That one thing made the ATX a huge advantage for me before I did anything else. I would not have believed it had I not had a White's Surf PI along for backup and sure enough, when I fired it up, the EMI was there. It was discernible in the ATX non-motion mode but even then nothing to worry about. I. Do not know what Garrett did or if I have a magic ATX but this one thing alone really floored me. It absolutely eliminated my number one problem with the Infinium. Basalt cobbles in sand on Kauai A detector with all controls set to max is in theory getting the best depth. But if it is not stable you cannot work with it, so you have to adjust back to find the best balance. The ATX is a very powerful detector and so I found a combination of settings that worked for me to get quiet, stable performance. This is in no way being advertised as a setting to for you to use! It is what I did for this location and other locations will take different settings. In general, the more powerful all your settings can be the better while still being able to have a stable running detector. So the ATX with factory default (minimum) ground balance, zero discrimination (pulse delay), and max gain would be at its most powerful. The worse the conditions, the more you may need to dial the settings back. The problem is with all the settings maxed out the ATX is very sensitive to small gold, but that also means it picks up salt water and hot rocks. I played with the gain control and the pulse delay (disc) control looking for a balance that left the detector running quiet. A discrimination setting of three and a gain of seven made the ATX submerged in salt water run like a VLF. I periodically reduced the disc setting or bumped the gain higher and noise was introduced, so settled on the 3 and 7 setting for my Kauai beach. Then I found a fat basalt rock buried in the sandy bottom and ground balanced over it, eliminating the signal. I would be the first to admit these settings were probably aggressive and of course costing me some depth in theory, but I got what I have always wanted in Hawaii. A PI detector running quiet as a VLF and by that I mean just purring along with a threshold sound, and when it made a noise, it was because I had a target under the coil. Here is another way to look at it. A very hot detector will detect salt water. It will detect hot rocks. And it will detect things you want. EMI can also be an issue. The trick is to reduce the signals from the things you do not want to hear as much as possible while enhancing the good signals as much as possible. It may be letting unwanted signals through will also increase depth on desired targets a bit. It may also be true that too many signals from undesired targets will inhibit success. You have to decide for yourself where the balance lies. If maximum depth is the goal then digging more undesired targets may indeed pay off. In my case I had plenty of targets, so the goal was quiet, efficient operation. I would not hunt clean white sand set like this. I would have the settings maxed out. I had a strategy in mind here, and my goal was to detect in the basalt cobbles. I was not tuning the machine for maximum performance in the easy stuff, but for maximum performance in the worst stuff. I wanted to detect the places where targets were more likely to have been missed by other detectors. Finally, after one go with the stock coil, I switched to the 8" mono coil. A few reasons. First, it is easier to handle underwater and fits in depressions better. It can be pushed through sand ridges and is less likely to move on the shaft. And I could find items edge on with it easier than with the stock coil. By that I mean turn the coil on edge and drag it in the sand and it acts like a pinpointer on small surface targets. The edge of a mono coil is very sensitive. A smaller coil is easier to pinpoint with to start with anyway. And honestly, I used the 8" mono because I was worried about sand getting in the twist locks and giving me problems, possibly even seizing up the rod assembly. The 8" mono and shaft assembly was my sacrificial lamb. If it got totally screwed up my stock coil would still be fine. Garrett ATX with 8" mono coil (goodie bag attached to arm strap, waterproof watch on handle) I may as well relate now that I did have issues with sand in the twist locks but not as bad as anticipated. The lower two twist locks seemed just loose enough that at the end of every outing I just worked them back and forth and the rod in and out and they cleared. But the upper one gave me problems. It got sand inside that refused to come out, even after taking it off and working on it under running water for a half hour. For some reason that upper most twist lock was just a bit tighter to start with and the sand would not clear out. Yet it never quit 100%. I lost most of the ability to twist the lock but it still twisted just enough to hold the rod in place. I am asking Garrett for advice on where to drill a couple holes or maybe slots to see if we can get these things clearing sand a bit better. Overall I actually am ok with them but they need improvement. In other types of sand it could be a big problem. I am going to see if I can get my upper lock to loosen up similar to the lower two and will report back later. The rod assembly got scored up quite a bit from being extended and collapsed with sand in the assembly. I will post photos later. Nothing that bothered me but some might hate seeing their expensive detector getting ground up like this. I have to say at the end of the day the physical design and the rod assembly in the water were nothing short of brilliant. I have given the ATX low marks for prospecting as being a duck out of water. The waterproof design adds weight, complexity, and expense not required for most dry land prospectors. But in the water the ATX felt really, really good on my arm. It is slightly negative so will settle on bottom if released. But not much; it is essentially weightless on your arm underwater. The rod assembly was a dream. I was working in heavy surf with 40 lbs of lead weight on. I steadied myself many times by leaning on the ATX with absolutely no fear it would break, and the rod never slipped. I could get in the shallows on my knees and shorten the rod down as short as I liked. And just right, no fumbling for the right holes, just loosen a twist lock or two and put it right how I wanted it. Better yet, due to the three piece design, I could also extend the ATX to be longer than any detector I have used underwater. I was in 6 foot of water with just my snorkel in the air, and easily detecting around me. I do a lot of breath hold recovery in deeper water and the ATX was just so easy to adjust for whatever depth I was working at. So easy and so solid and tough that I 100% forgive any little work needed to sort out the twist lock situation. This is one really great handling detector underwater in rough surf conditions that would leave other detectors in serious danger of breaking. The 8" mono was perfect for me. It stayed where I put it and I pushed it around a lot. I learned quickly if I wanted to adjust the coil position to be flatter all I had to do is turn the detector over and push down on the nose of the coil. Maybe not as easy as pushing down on the heel of a coil with a rod mounted in the center instead of the rear but no big deal, mainly because the coil stayed put. After two weeks of heavy use I never had to adjust the coil tension and it showed no signs of having any issue with all the sand it ran through. I had no scuff cover, and the coil shows no sign of cracking, just your normal scuffing from use. The epoxy appears much improved from the old Infinium days. A weak point - that tiny spring loaded rod lock, the one you flip to disengage the rod and coil assembly. The tiny spring popped out on me once. I took it apart, made the spring end ninety degrees again, and it worked for most of trip, but slipped out again last day. Not a big deal but needs beefing up. Be sure when twisting the rod and cams while cleaning to not hold the detector body. You will be twisting against that little lever. Hold onto the rods themselves and twist the cams. We need to find out what the part number is for the coil and headphones connector covers. Everyone should have a couple extra. Better yet, a couple spare caps like are fixed to the back of the ATX to cover the male headphone connection when not in use. One of these to put over the male coil attachment point inside the housing would be very helpful when rinsing and cleaning the ATX. Take the coil off, put the cap on, and now no worries while cleaning. I will find out the part numbers and pricing for those and get some and suggest ATX owners do also. I saw no point on beach hunting with all the competition. One guy in particular walked the beach a couple times every day with a Surf PI. I saw a couple Surf PI detectors at work, a Minelab Excalibur, and a Tesoro Sand Shark or Piranha. They all walked the beach and only the Excalibur guy ventured into the trough when it was calmer once. I spent all my time in the surf or deeper water with a weight belt and mask and snorkel. I recover targets by fanning or digging. And I went looking for mixed coral/basalt harder bottoms instead of deep sand. I played on the beach a bit and hit deeper sand underwater but basically all my finds came off of more solid bases. I am not going to say the ATX was some kind of super depth monster. That would be misleading and really missing the entire point. I have no doubt it was getting as good as depth as could be wrung out of the conditions. I was easily getting nickels down to ten inches in the basalt, maybe a tad deeper but honestly it is hard to tell recovering targets underwater while holding my breath in the surf. The real thing I am trying to relay here is the ATX was rock solid, just like using a good VLF above water, but in the worst detecting conditions I have ever encountered. It allowed me to just get on with the business of detecting targets and recovering them. If I was lacking for targets maybe fighting for another inch would be the name of the game but I never ran out of targets. Steve's Finds in Hawaii with Garrett ATX (Click on photo for larger version) The rings just banged! Nickels hit hard. By virtue of the ground balance system large junk goes low tone and I ignored many low tone targets. That cost me some dimes, copper pennies, and quarters but that is ok. Nickels, zinc pennies, and rings go high tone. As do sinkers, bottle caps, hair pins, and aluminum. Still, being able to ignore low tone targets upped my odds some. Though I dug a lot of low tones also just to learn more and frankly, because I have a hard time passing targets. You just never know for sure until you dig them and I was there to dig targets. Still, this photo shows my target mix skewed to high tone targets. With the exception of a few large items discarded at the trash can this is every item I dug over the two week period and about 50 hours of detecting time in the water. Another benefit with the ATX is the adjustable target volume and threshold, a real boon in an underwater detector. I had brought Gray Ghost Amphibian phones with me that started out loud enough but then got too quiet to hear, so I had to FedEx a set of Garrett phones in quick. I like the sound of the Ghosts better but not if I can't hear them. I surmise the sound chamber was filling with water and so will return them to get checked out. First time DetectorPro phones ever let me down. The Garrett phones have a lower tone but worked just fine. The volume and threshold control on the ATX makes them much nicer to use since they can be set comfortably for both above and below water use even though they have no volume control themselves. You can even set the volume on the fly easily while underwater. This is a very nice thing that most underwater detectors lack. I have read a few posts by people very concerned about the placement of the headphone connector. Total non-issue for me. It is under my right elbow and was never a concern at any time. Icing on the cake? The ATX retains all settings when turned off. Once I found my magic settings I was so happy with how the ATX was running I was afraid to change anything and did not have to. Just turn it off, turn it on, and ready to go. Everything is just the way you left it. This is very important with the ground balance setting. It is the one setting you have no idea where it is set. I wish and am suggesting that when the detector is manually ground balanced the LED indications reflect the entire range and show you where you end up at for future reference. Right now the LEDs simply follow to audio and reduce to nothing when the unit is ground balanced. But where am I and can I get back there? You have no idea and neither did I. All I knew was my ATX was running great and recovering targets at what I thought was good depth so I left it be. I used rechargeables exclusively. I kept rough track of detecting time and charged up about every ten hours. Again, it was nice being able to pull batteries out, charge, reinstall, and when the detector was turned on again no tuning was required due to the retained settings. I carefully looked for water in the battery compartments each time but never saw a drop. I have total faith in the waterproof integrity of the ATX after what I put it through. I just got back and blasted this report out but will probably edit it a bit to smooth it up over the next couple days. I will also post a more story like version with more details and photos on my journal in the next couple days. I am cleaning up a few of the rings. There is one very old class ring I thought was junk but is encased in sand and lime I am dissolving away and I have a couple silver rings to clean up. Once again the big diamond eluded me but no complaints here, it was my best haul ever for a beach hunting trip. In no small part due to the Garrett ATX but I will take some credit also for really hitting the water hard. So here are the rings. The bottom line is I just had my most successful trip to Hawaii ever. I recovered over a couple dozen rings with the ATX and half of those were gold or platinum. Some silver rings, a nice 14K bracelet, and a pile of coins and the inevitable PI junk. This despite bad weather early on and all the extra detecting competition. Eight Gold and Two Platinum Rings Found by Steve Herschbach with Garrett ATX in Hawaii Another view later after the better silver rings were cleaned up, and that fabulous bracelet Again though, do not take this as some kind of crazy ATX testimonial. Pay attention to my caveats. Beach hunters in clean white sand with tons of hair pins have less to be excited about here. But if you have black sand beaches or worse, the ATX is a machine to at least be aware of. I just can't help it though, I really like a detector that puts gold and platinum in my pocket! Things I most wanted? An indication of what the ground balance setting is and an ATX version of the 14" Infinium mono coil. Thing I liked most? The way the ATX handled in the water and the way it adjusted up to handle the conditions. My last detecting nut cracked - thanks Garrett and especially Brent Weaver for obviously listening to my suggestions all these years! I would like to learn more about this detector as there is much it is capable of. How exactly does it compare with factory default minimum ground balance mode versus PI detectors that have no ground balance at all? I tried the no-motion mode a bit but saw no real value for what I was doing - there has to be more to it that is of value in other situations. Most importantly, what combination of pulse delay, gain, and ground balance is optimum for various locations and targets? I found some that worked for me but I am not swearing they were the best settings possible. I admit to focusing more on detecting than fiddling and so it is hard to get me to stop and do comparative tests when detecting time is at a premium. I look forward to seeing what works for others and will add what I can as I learn more about the ATX myself. This article was promoted from a thread on the DetectorProspector Forum and those interested in the article will find additional information in the posts on that thread. ~ Steve Herschbach Copyright © 2014 Herschbach Enterprises Steve's Mining Journal Index
  6. 1 point
    The two best-selling professional metal detectors in Alaska over the last twenty years are probably the White’s Electronics GMT and White’s Electronics MXT. This is because a set of local circumstances favored these two detectors. These two machines are based on the same circuitry, but have very different design goals and therefore features which determine which might be the best choice. Since the sole purpose of the GMT is prospecting, it operates at a high 48 kHz for extreme sensitivity to small metal items... hopefully gold nuggets. It is not a "gold-only" machine in that it picks up all metals. The "gold-only" detector has yet to be invented. It does however have a very efficient system for separating ferrous (iron or steel) items from non-ferrous items (gold, copper, silver, lead, aluminum, etc.) In theory the GMT could be used for other types of detecting, but it has a couple serious problems. First is the fact that it is so sensitive to small metal! Any attempt to use it for typical coin detecting would leave a detectorist quickly frustrated. Imagine a foil gum wrapper sucked into a lawn mower, shredded, and spread about. Parks and other areas popular with coin hunters are full of tiny aluminum trash. Every one of these items will sing out loudly on the GMT. Coin detectors are purposely designed not to pick up these tiny non-ferrous items as 99% of the time they are trash. The GMT also is very sensitive to wet salt sand, and so is useless for most beach detecting. It would not be impossible to use the GMT for other detecting tasks, but in general it really should not be considered for anything other than nugget detecting. The MXT was built using the GMT circuitry. An advanced LCD readout discrimination system similar to that on top-of-the-line coin detectors was added. The frequency was lowered to 14.7 kHz to increase the sensitivity to coin type targets and to moderate the problem of being too sensitive to tiny trash. But the frequency is still well above that of standard coin detectors which work around 6 kHz so the MXT retains much of the GMT ability to hit gold targets. The MXT has three distinct modes: Coin & Jewelry, Relic, and Prospecting. Each mode dramatically changes both the sounds and the LCD readouts generated by different targets. The Coin & Jewelry mode is very much like any standard coin detector, but with a better than normal sensitivity to gold coins and gold jewelry. The Relic mode is a rather unique dual tone mode that operates in both all-metal and discriminate modes at the same time. That alone is subject for another article! The Prospecting mode in effect turns the detector into a GMT, but one that runs at a lower frequency and that lacks a manual ground balance. And the MXT has a special Salt setting to allow it to work on those beaches. White's GMT versus White's MXT The GMT is admittedly superior when it comes to picking up small gold. It can hit specks weighing less than 1/10th of a grain (480 grains per Troy ounce) while the MXT will need nuggets weighing 2-3 grains to get a decent signal. But on the flip side, the MXT may very well be the superior unit for large nugget detecting. The lower frequency actually is smoother in mineralized ground, and in particular does not produce as many weak variations in the threshold in mixed cobbles as the GMT. The drawback of higher frequencies is that while small gold produces a sharper response, so do hot rocks. The manual ground balance on the GMT is very helpful for hitting those tiniest specks, but less useful for larger gold. If larger gold nuggets are the goal, then the MXT is every bit equal, if not better than the GMT in overall performance due to the smoother ground handling capability. It’s not that the MXT goes deeper, it just has less issues with hot rocks while still being able to hit those larger nuggets. In milder ground the GMT reigns supreme. For Alaska those wanting to go places like Crow Creek or Mills Creek and have a chance of getting gold, any gold at all, will be best served by the GMT, especially if paired with the little 4” x 6” Shooter coil. It will get the gold in these heavily hunted areas, and will hit gold the MXT will miss. But if versatility is important, or chasing large gold nuggets in tailing piles at Ganes Creek is the goal, the MXT is the way to go in my opinion. It is simply one of the best all-around detectors I have ever used. The White’s MXT Engineering Guide is full of interesting information on the development of the GMT and MXT and provides a rare look at what goes on behind the scenes at a metal detector company. ~ Steve Herschbach Copyright © 2010 Herschbach Enterprises
  7. 1 point
    *Notes on specifications: This page is a footnote link in all "Steve's Reviews" - metal detector and gold prospecting equipment reviews by Steve Herschbach. Two basic technologies are described here; Induction Balance (IB) and Pulse Induction (PI). Induction balance is often referred to as VLF, or very low frequency. This is a misnomer, as some gold nugget detectors and some coin detectors are not very low frequency units as normally defined. VF = Voice Frequency = 300 Hz - 3 kHz, VLF = Very Low Frequency = 3 - 30 kHz, LF = Low Frequency = 30 - 300 kHz. Most IB gold detectors operate in the Low Frequency Range and quite a few coin detectors operate as low as the Voice Frequency range. Pulse Induction (PI) detectors operate over hundreds of frequencies employing a totally different technology than IB detectors but can be best imagined from an operational standpoint as Low Frequency detectors Internet Price - Manufacturer's often publish manufacturer suggested retail prices (MSRP) intended to set the full value of an item. In the United States they also will often set a minimum advertised price (MAP) that determines the lowest price that can be used for advertising purposes. Note that this is not the lowest price an item can be sold for but instead is what you will normally see in print ads or online as the lowest advertised (sale) prices. The Internet Price in the chart is the normal advertised sale price as commonly found on the internet as of the date listed. Dealers will often try and sweeten the deal by including "free" items in the advertised prices. You can often negotiate a lower price by contacting the dealer requesting a lowest price for the item without all the "free" package items. Technology - The basic operating technology a detector uses has a huge impact on how it behaves. Early consumer 1960's model detectors commonly employed a method referred to as Beat Frequency Oscillator (BFO). This simple design can be built by a school child with a handful of components. The search coil or loop was literally a coil or loop of wire. They are noted for making a distinctive "putt-putt-putt" continuous beat. The beat increases as a target is detected and the BFO responds to both conductive metals and magnetic minerals. The early 1970's saw the appearance of the Induction Balance (IB) detector. The IB detector employs two coils, a transmit and a receive coil, that are kept in electronic balance. They were therefore also commonly referred to as Transmitter/Receiver (TR) and that term saw more popular use. The TR produces a steady tone that increases in volume and the early TR models, like the BFO, responded to both conductive metals and magnetic minerals. The BFO and TR were both very limited because their ability to detect magnetic minerals interfered with their ability to detect conductive metals. An IB or TR variant was developed that allowed the detectors to not only eliminate the signal from ground minerals but to discriminate between various metals. These detectors ran at lower frequencies than the TR models and referred to as Very Low Frequency (VLF) detectors. Dual mode models existed, the VLF/TR, but the TR modes were so limited they were eventually dropped in favor of pure VLF operating modes. Almost all such detectors are referred to as VLF detectors today, but VLF is actually a misnomer. In electronics, VLF refers to the 3 kHz - 30 kHz frequency spectrum. There are detectors operating at under 3 kHz, and so technically they are Voice Frequency (VF) detectors. There are also many models operating over 30 kHz which are technically Low Frequency (LF) detectors, although because they are operating at higher than VLF frequencies many people refer to the as "high frequency" detectors. Therefore on this website the more technically correct term Induction Balance (IB) will be used. This is important because IB detectors are dramatically different than the other major technology employed at this time, the Pulse Induction, or PI detector. The IB detector requires two coils or loops that continuously transmit and receive in electronic balance. The PI detector requires only one coil but may use two. Rather than transmit and receive continuously, the PI detector transmits, pauses, then receives, which can be done with a single coil. The PI detector is able to ignore salt water and mineralized ground that an IB has difficulty with. This makes PI detectors particularly well suited for salt water diving applications, and that is where most consumer models have been aimed over the years. Simple PI detectors are often advertised as having "automatic ground rejection" but that is not strictly true. A normal PI will ignore common ground conditions, but they still are affected by highly mineralized ground and hot rocks, and so are not suitable for most prospecting applications. A company in Australia recognized the potential however, and developed PI detectors aimed specifically at the prospecting market. These detectors do actually ground balance, or tune out the effects of highly mineralized ground and hot rocks, and so along with other models now on the market represent a subset of the PI detectors, the Ground Balancing Pulse Induction (GBPI) detector. Frequency - Induction Balance (IB) detectors as radio devices normally operate on one of more frequencies that govern certain operating characteristics. The transmit frequencies are often quoted but what is most important is the frequencies the detector receives and actually processes. Most detectors receive and process a single frequency but a few detectors receive and compare the results of two or more frequencies. The focus on frequency has lead some marketing people to advertise multiple transmit frequencies in ways that are a bit misleading because people assume more is better. The reality is single frequency detectors excel at some tasks and multi-frequency detectors at others. Single frequency detectors can be better honed for specific tasks, such as nugget detecting. Multiple frequency detectors are better able to handle salt water environments and generally excel at target discrimination. In general, the higher the frequency, the more sensitive the unit is to small gold, but also more affected by mineralized ground and rocks. Lower frequencies penetrate mineralized ground better but are less sensitive to small nuggets. Multiple frequency detectors have historically acted like lower frequency detectors but newer models are so sensitive as to be practical for gold nugget detecting. Frequency article Pulse Induction (PI) detectors are sometimes advertised as using huge numbers of frequencies, which is technically true, but again is the marketing people going to work. Operating frequencies on IB detectors do not really equate with PI detectors which operate on a different principle. The closest specification in a PI detector that has some bearing on the operating characteristics is the Pulse Frequency which is the number of times the transmitter pulse is repeated every second. It is usually quoted at Pulses Per Second (PPS). The pulse frequency affects the response time (slower PPS call for slower sweep speed), power consumption (higher PPS uses more power) and interference rejection (adjustable PPS helps adjust out electromagnetic interference). Pulse Induction (PI) detectors again are a special case, and the sensitivity to small items and ground minerals is more affected by the Pulse Delay than the Pulse Frequency. The Pulse Delay is the wait time between the transmit mode and receive mode. The shorter the delay, the more sensitive the detector is to small items and hot rocks. In theory a PI can be just as sensitive as an IB detector by operating at extremely short delay times, but then it would suffer the same problems as an IB detector. PI detectors designed to hunt gold often have a pulse delay of about 10uS (microseconds). Salt water however signals at 10uS so salt water PI detectors often run about 15uS. Some PI detectors can have an adjustable pulse delay that commonly runs from 10uS to 25uS. Autotune Modes - Almost all modern detectors require the search coil to be in motion over the target to get a response. Nugget detectors employ automatic threshold tuning, which acts to help keep the threshold tone even in variable ground. The circuit seeks to return the threshold to a level preset by the threshold control. The retune rate can vary from slow to fast and in some cases can be adjusted by the operator. Holding the coil stationary over the target causes the target to disappear as the autotune circuitry brings the threshold back to the preset level. Detailed article Ground Rejection - Ground rejection or ground balance can be set at the factory (Pre-Set), manually set by the user (Manual) or automatically track ground conditions (Tracking). Fixed refers to units that lock in whatever setting the automatic system has at any moment but which cannot be manually adjusted. Manual adjustment allows a unit to be purposefully adjusted to specific conditions that cannot normally be attained through manual or fixed settings. The preferred option is to have both tracking and manual ground balance systems. A compromise between manual ground balance and ground tracking is an automatic "Grab" function. This allows the unit to be ground balanced by pressing a button. The ground balance setting is obtained instantly or with a few pumps of the coil over the ground. Soil Adjust - This refers to a control that allows the operator to adjust the unit for basic ground conditions. Common settings are Normal, High Mineral, Low Mineral (Sensitive), Salt (for salt water beaches or salt flats) or a variable setting. The technology employed may vary. The unit will compensate for difficult conditions by basically lowering the overall sensitivity of the detector in various ways so as to not detect the item or items causing problems. The sensitivity to desired items almost always suffers as a result. Discrimination (Disc) - Most detectors offer all metal detection, all metal with ferrous (man made iron or steel) rejection, possibly adjustable, and fully adjustable discrimination that can actually identify different non-ferrous targets one form the other. The method may be audio only, via a visual display, or both. A control that allows for only ferrous items to be rejected to a varying degree is commonly referred to as "Iron Mask". Volume Control - Detectors with volume controls usually have a built in speaker and this way you can adjust the speaker output. Detectors without volume controls operate at full volume at all times. Be sure and purchase headphones that have an adjustable volume for these detectors or the headphones will be too loud to use. Tone Adjust - This allows for a change of tone in the speaker output, to the sound that best suits the user's ears. Some people hear high tones better and some people better hear low tones. Audio Boost - Boosts the audio volume on small, faint targets, making them easier to hear. It may also boost ground and hot rock signals in some areas and so is usually offered as an option. Frequency Offset - Two detectors operating on the same frequency close together will "cross-talk" or cause some kind of false signals in both nearby detectors. A frequency offset or adjust allows for a small change in frequency so detectors are less prone to interfere with each other. The control may also alleviate interference from outside sources like power lines or cell phone towers, referred to as EMI (Electro-Magnetic Interference). Pinpoint Mode - Common in coin detectors, rare in gold nugget detectors. The pinpoint mode is usually a variation on the all metal non-motion mode (see Search Modes above) that allows the detector to be held steady over a target as an aid to locating the exact position of the target. This may be of some benefit in some "silent search" that lack a threshold tone and which only make a sound when passing over a target. The mode is usually activated via a momentary push button or trigger switch. Audio Output - Nearly all detectors have a built in speaker and a 1/4" headphone jack. Others vary from the norm and are so noted. Also, be aware that some detectors have a mono output and some have stereo output. This is noted when known but it is best always to have headphones that can operate in either mode. Headphone notes Hip Mount - Some models allow the control box to be put on a belt or chest harness. A very desirable feature, as even a lighter detector can cause arm soreness, or even injury, if used for long periods of time. New detectors are so light this is now a rare feature more often seen on older models. An exception are the Minelab SD/GP detectors in that they are heavy, but through the use of an ingenious harness and bungee system they actually impose less arm strain in level ground than most detectors. Similar harness/bungee systems can be obtained for use on most detectors from aftermarket sources. Chest mounts however are still a valuable option for those thinking of using their detector in deep water. Standard Search Coil(s) - The search coil or coils that come that come with the detector. Also referred to as loops. IB detectors have concentric or double D (DD) options. PI detectors have mono or double D (DD) options. Concentric or mono coils are usually more sensitive but more affected by ground mineralization. Double D coils handle ground mineralization better but at some loss of maximum depth in low mineral conditions. Concentric or mono coils have an inverted cone detection pattern with maximum depth dead center that fades off in all directions. DD coils have an elongated inverted canoe pattern that covers the ground more thoroughly but lacks the maximum depth dead center that concentric or mono coils offer. Large coils get more depth and cover more ground than small coils, but lack sensitivity to small targets. Small coils lack overall depth but enhance sensitivity to small targets and have better target separation by not "seeing" two targets under the coil at once. Large coils are more affected by the overall ground mineralization, small coils are more affected by hot rocks. Suffice it to say that the more coil options one has, the better. Coil compatibility Optional Search Coils - See the note above. The more, the better. Battery - Options are usually disposable batteries, rechargeable systems, or both. Common battery types are AA batteries and 9V batteries. Disposable batteries tend to fade away slowly as they lose power. Rechargeable batteries maintain a more even power output then go dead very rapidly. Rechargeable are preferred by heavy users and a backup battery is a necessity. Operating Time - Normal battery life in operation with standard battery. Note that the use of headphones will significantly extend operating times. Weight - Weight of unit on arm with a few noted exceptions. Additional Technology - Features offered by this detector not normally seen on other models. Notes - Anything else of interest about the model in question.
  8. 1 point
    My wife and I finally took a long-awaited vacation to Hawaii. We returned to the same location we had visited previously on the island of Kauai as it was really our kind of place. My wife mainly likes to lay in the sun and read. I like metal detecting the beaches and surf. So it works out well... she parks herself on the beach and I wander around nearby with my detector. My last trip to Hawaii three years ago produced only one gold ring in two weeks. See the story here for details on that trip. I was determined to do better this time. I took two detectors, my Garrett Infinium LS, and a new Minelab Excalibur 1000. I have a Fisher CZ-20 that I have been very fond of for freshwater hunting, but many have advised me they thought the Excalibur might do better in saltwater than the CZ-20, although the two machines are very close in performance. My main goal was to use the Infinium, but I wanted a back up unit. In particular, I had discovered some beaches off Kauai have lots of iron trash due to the two hurricanes that hit the island in the last twenty years. PI detectors like the Infinium tend to find iron items while VLF detectors are good at tuning it out, and the Excalibur is particularly good in this regard. I was most anxious to use the Infinium after my success with it nugget hunting in Alaska, but the first time in the water with the Infinium it binged and bonged and made all sorts of noise. I thought, "This is a heck of a note" and went and got the Excalibur. I had no patience at that point; I wanted to find stuff now. I found lots of coins with the Excalibur and finally a gold ring. The Excalibur was very quiet and handled the salt water environment about as well as I think a VLF detector can. But the fact is that a salt water/volcanic soil environment like Hawaii severely impacts the performance of VLF units, and so the depth of detection I was seeing with the Excalibur was not what I would be expecting with a PI detector. Detecting heaven - Poipu Beach, Kauai, Hawaii I gave the Infinium a try on the beach to see what the story was there. I found I was getting noise off the salt sand at the end of my swings, and remembered the note in the owner’s manual about this very thing. It is instructed that the discriminate control be advanced to reduce these signals. I was about to say "false signals" but they are nothing of the sort. The Infinium is a particularly sensitive pulse induction detector. If you tune PI detectors up for their best sensitivity to small gold items you run into the area where saltwater, being a low conductive item, also starts to be detected. The Infinium at its zero discriminate setting picks up wet salt sand and saltwater. It is not a false signal, just a response to a low conductive target a less sensitive unit would not detect at all. This effect is enhanced by the 14" coil, which "sees" a large volume of material. By advancing the discriminate control to the point at which the salt effect is tuned out you will get stable operation. In theory this also means that some depth of detection or target strength will be lost on smaller low conductive targets like gold earrings. One thing I need to do in the future is test the Infinium at various disc levels to ascertain the effect on target responses. As a practical matter it does not matter. Just as the sensitivity of a hot VLF detector like the Fisher Gold Bug 2 must be backed off to compensate for high mineral ground, so to the disc control on the Infinium must be set to compensate for the conditions encountered. Hot VLF units cannot be used on wet salt sand at all since they see the salt water as a target and no amount of tuning will get a high frequency VLF to work properly on wet salt sand. Steve with Garrett Infinium on the beach trying 10" x 5" elliptical DD coil I did much like I would with the sensitivity control on a VLF detector. I adjusted the disc control to where I was on the edge of stable operation. In other words, I was running with a bit of background noise. Some people might prefer to go farther to eliminate such noises entirely, but I am used to running "on the edge" so to speak. I found the Infinium with 14" coil set at 3-4 disc level gave not quiet but acceptable background sounds on the beach. I proceeded to dig coins and a small toe ring. As I have found in the past the Infinium really likes nickels. I seem to always find a higher percentage of nickels than I would normally find with a VLF detector when I use the Infinium. This is because it is optimized for targets that fall in the nickel range, like most gold items. Armed with my newfound knowledge I gave the Infinium another try in the surf. And I do mean surf. I had on 40 pounds of weights to help me stay put as the waves crashed into and over me. When I get a target the weights allow me to duck to the bottom and stay put while excavating the target. I use the “fanning” method of blowing sand away with my hand. I’ve tried scoops for this but frankly I’ve got my hands full just hanging on to the detector while working. In high-energy surf the scoops just seem to get in my way. One thing I have heard speculation on is that the 14” coil might be a problem in the water due to its size. That did not prove to be the case for me. The Infinium is weightless underwater and the feel was good. I had no problem using it in very rough surf and in fact often was forced to brace myself on the bottom with the detector. We are talking adverse conditions at their worst, and the Infinium did fine. I found a disc setting of 5-6 was required underwater, and even then the coil needed to be kept parallel to the bottom. When I ducked to the bottom to get a target, the coil would turn up and point off into the water. It could then “see” more salt water, and start to signal. But I was so busy holding on and digging targets I really did not notice this much after a while. Steve suited up for metal detecting in heavy surf But lo and behold, the deep targets started coming… and the rings! First real surf dive of about three hours with the Infinium produced three beauties. An 18K gold and platinum ring was first, followed shortly by a 14K gold ring. Then a lull while I dug a few coins and nails (the Infinium does pick up large elongated iron objects the Excalibur ignores) and then a GREAT BIG GOLD RING! I was over a foot down, and expecting a big chunk of trash, when up pops a large class ring - 1963 U.S. Air Force Academy. It is a 14K gold ring with a large synthetic blue star sapphire. It looked incredibly large underwater, and is the most massive ring I have found to date. I'm working on finding the owner of this one. I was really stoked, but this was Sunday morning, the day before I was to leave. Some beach work with the Infinium and water work with the Excalibur had up until this point produced about 100 coins and one gold ring. But now that I had the Infinium figured out I had three great rings in less than three hours! The surf really beats me up, so I took a break and spent time with my wife. But that afternoon I hit the water again, and up comes an 18K gold ring with a deep blue faceted sapphire and a platinum band. The depths were all in excess of what I feel I was attaining with the Excalibur. I do not want to give the impression I’m knocking the Excalibur. It is a well proven and well thought of detector, and may in fact have the best performance in salt water of any VLF on the market today. But I just do not think a VLF detector with a 10” coil has much chance versus a PI detector with a 14” coil in saltwater environments. We had to check out at noon the next day, but I got up early and gave it one last go. A few more nails, some coins, and on last extra wide 14K gold band. I was ecstatic… it just seemed like I could not miss with the Infinium. In two days I found more nice rings than I've found in any other water detecting I've undertaken. My only regret is I did not try harder with the Infinium right off the bat. I found the Infinium to be a very good saltwater unit, but not having run any pulse units other than the White’s Surfmaster PI in salt water I certainly cannot say how it compares to other PI water detectors. Even the Surf PI I used three years ago has been upgraded to the Surf PI Pro model for enhanced sensitivity to gold items. That fits with what I experienced with the original Surf PI. It got the coins but left me with little gold to show. I would like to try the PI Pro as it is lighter and more streamlined than the Infinium. At $699 list it is also quite the bargain for someone wanting to try a PI detector for water detecting. But the Surf PI Pro also lacks the ground balancing capability and interchangeable coils that make the Infinium so versatile. The key for anyone using the Infinium around salt water will be to get the disc control set properly. I cannot overemphasize this point. It is the single most important adjustment for making the Infinium work in salt water, and my initial lack of knowledge in that regard cost me precious hunting time. I really think the Infinium disc control can be more properly thought of as a sensitivity control, and the key is to back the sensitivity down to a level that gives stable operation. Do not be concerned about lost sensitivity. I think I proved the machine retains plenty of power. But if you are picking up the saltwater itself you certainly will have little luck in detecting anything else. Still, I should add a cautionary note here. The Infinium WAS noisy! That means different things to different people. For me, as a long-time detectorist, it is just a thing to be dealt with, and I am used to running detectors "on edge". In other words, I often tune detectors to their limits, which many times results in noisy and erratic performance. The difference is that I can tell the difference between "good sounds" and "bad sounds". But someone else listening to what I am doing might not hear the difference, just lots of noise. So lest this story sound like a glowing reason to run out and get an Infinium do take note of its noisy performance here. I obviously made it work for me, but some people may not like either the noise, or the amount of discrimination required to reduce the noise to normal levels. For dry land use, especially while nugget detecting, I feel the Infinium is a very good detector. In salt water the results are mixed, and will depend a great deal more on the expertise of the detectorist. The White's Surf PI was a much smoother and easier to operate detector by comparison, and may suit the casual operator more than the Infinium if salt water is the sole intended use. The Excalibur is the only VLF detector I have ever used in salt water. It was much quieter in operation than the Infinium, although it constantly gave multiple tones on each target instead of locking on a single tone. It did a superb job of ignoring iron targets, and if there were enough iron targets it would certainly be the way to go. But the amount of iron I dug with the Infinium was nowhere near the level it would take to discourage me, and the bit of extra depth I feel I was getting with a PI made me feel more than happy to dig the few iron targets. The ratio was no worse than one iron target for every two or three non-iron targets. I think that unless iron trash is a problem PI is the way to go. I'm surprised that Minelab, manufacturer of what many believe are the most powerful PI units in the world, does not build an underwater PI unit. On the other hand, I have some fresh water lakes I hunt in Alaska that are full of iron trash, and I am anxious to use the Excalibur in those lakes. Iron junk, rings, coins, aluminum trash, and lead weights found metal detecting The picture above shows a typical mix of finds, although some of the oversized trash items have already been discarded. The first place I usually head after getting out of the water is the nearest trash can. In fact, I try to make a spectacle of myself disposing of the trash, especially the sharp glass I retrieve. It helps promote the image of detectorists as public servants. Hey, we are just getting this dangerous junk out of here. The iron items were all found with the Infinium. The Excalibur ignores iron better than any detector I have used. The majority of the coins were found with the Excalibur, although the Infinium got its share, especially nickels. Almost all the pull tabs were found with the Infinium, again confirming its power in the gold range. Many rings are identified by metal detectors as pull tabs because of their similarity electronically, and so the Infinium likes them also. Notice also the large fishing sinkers found by both detectors. I gave these to the dive shop I rented my dive gear from. If you are planning on doing some surf detecting in Hawaii, here is how I outfit myself. Obviously you need some kind of underwater detector. I prefer two, as I have had two different underwater detectors leak on me over the years. The chances are slim, but vacations like this are few and far between. It's cheap insurance. I use a neoprene shorty suit while in the water. The water in Hawaii is warm, but it can get chilly if you are fully submerged for some time. I also find the suit helps cushion the weight belts to prevent chafing. I used two weight belts totaling about 40 pounds. The weight belts and suit were rented locally. Each item was $18 for the week, for a total rental of $54.00. Next time I plan to have a suit with long legs to protect my knees while down on the bottom. I wore an old pair of tennis shoes and socks while in the water. There are lots of rocks and coral that can chew your feet up, not to mention spiny animals like sea urchins. This seemed to work very well and I would do the same thing again. I have a mesh bag that I attach to the arm of the detector for targets I retrieve that also has worked very well. It has a hooped metal opening that makes it easy to drop items in the bag, and yet I have never had a problem with anything getting out of the bag. I have a mask and snorkel that I have used for dredging and diving for many years that continues to give good service. The snorkel is a U.S. Divers model that features a water catch and drain system near the top that sheds water caught by waves going over the top. A good idea for surf work. Finally, a good pair of neoprene gloves to protect my hands while digging holes or holding on to coral. The only item I wished I had was a small rock pick. Every once in awhile I would find items that worked down into deep holes in the dead coral bottom. I had to abandon some of these as the items were too far down in the small cavities. A small rock pick would have allowed me to open the holes up to find those items... whatever they were. Time for a safety warning. Surf conditions can be dangerous and working over weighted can be particularly hazardous. It is important to be completely comfortable in the water and to have a realistic knowledge of your limitations. I have made hundreds of SCUBA dives and have thousands of hours on hookah diving systems. I am extremely comfortable in the water and there is little that could happen that would cause me to panic. Do not attempt rough surf conditions without being sure of yourself and your equipment. All found with Garrett Infinium except small gold ring on pinky finger Index Finger - Two 14K gold bands Middle Finger - Platinum band and 18K gold w/faceted sapphire Ring Finger - 14K Class Ring w/synthetic star sapphire and 18K gold & platinum band Pinky Finger - Stainless steel toe ring and 22K gold band (Excalibur) As far as where to hunt? Well, on the beach itself there is a zone up above where everyone sits. Lots of coins there. But if jewelry is the goal you need to get into the body-surf/boogie board zone. And that is pretty much where the waves are breaking. A rock or coral base with no more than about a foot of sand on it would be preferred. You do want some sand to hide items when dropped, but too much and items sink beyond detector range. The sand gets stirred a lot in this zone, and so stuff gets deep pretty fast. Areas where lots of tourists are in the water will generally be more productive than areas the locals frequent. It's a more affluent crowd and one that is more ignorant of the effects of water on jewelry. Just make sure you take time to watch people a lot. Just sit on the beach and watch people at play and where they are doing it. Any of those areas have potential, and the more vigorous the play, the better the potential. It was a great trip, albeit too short. I’m chomping at the bit for another go. I have often gone on nugget hunting trips where it seems like I spend 3/4 of my time getting my bearings, and then really start to score just before I run out of time. This was one of those trips, and between my trip three years ago and this one I think I’m getting a handle on surf detecting now. I can guarantee it won’t be three years before I next hit the surf in search of gold. ~ Steve Herschbach Copyright 2003 Herschbach Enterprises Postscript 3/25/03 - A happy ending to the 1963 U.S. Air Force Academy Class Ring story. The class is celebrating their 40th reunion in 2003, and by contacting the reunion organizer I was able to find the owner of the ring. He lost it 17 years ago while body surfing in Hawaii and sure was surprised to hear his ring had been found. I hope he gets it refinished and wears it to that 40th reunion!
  9. 1 point
    This is not intended to get into every nitty-gritty little detail, but instead is a brief overview for those unfamiliar with the Minelab Pulse Induction (PI) detectors. The units released so far are the SD2000, SD2100 (and V2 variant), SD2200D (and V2 variant), GP Extreme, GP 3000, GP 3500, GPX 4000, GPX 4500, GPX 4800, and GPX 5000. The Minelab SD2000 was the first of the series, a genuine breakthrough in metal detector technology. It is the basis on which all the other models were developed. It was the first true prospecting pulse induction metal detector and it had a major impact in the Australian goldfields for which it was designed. The main drawback was a definite lack of sensitivity to nuggets weighing under a gram or two. The SD2100 and SD2100v2 are fairly simple manual ground balance units that refined the SD2000. The frequency could be manually adjusted to avoid interference from outside sources, such as a nearby detector. The SD2200d and SD2200v2 offer automatic ground balancing or a fixed/locked ground balance. They also introduced an iron disc feature of dubious reliability, audio boost, and automatic frequency offset. The GP Extreme offered enhanced sensitivity to small gold that was lacking in the earlier units. Much of this came about from Minelabs patented dual voltage technology (DVT) which was introduced with the GP Extreme and is featured on all subsequent models. There were quality control issues with the unit however and so performance varied on GP Extreme detectors. The GP 3000 is essentially just a refined GP Extreme and the GP 3000 performance is more consistent between units than was seen in the GP Extreme. Threshold smoothness was improved to be less erratic. The GP 3500 offered manual frequency tuning to help eliminate electrical interference and three tracking speeds for the automatic ground balance system. A button was added to the handle to allow for easy switching between the manual and automatic ground balance modes. The GP 3500 was the last of the analog models in the series. Where it all started - the Minelab SD2000 "Super Detector" The GPX-4000 was a break from the past, going to a digital control system. This allows for more adjustments but also more complexity. The GPX models can attain smooth thresholds on par with the best VLF units. A major advance is in the form of various optional "timings" that allow the detector to be customized for various types of ground mineralization and hot rocks that might be encountered. The earlier SD and GP models used a sealed lead acid battery with a 4 pin battery cable. GPX models feature a Li-Ion battery with 5 pin cable that is not compatible with the earlier models. The GPX-4500 is a basically a refined 4000. A pattern develops by now in that Minelab tends to make a major model revision, then follow up with another model that is just a refinement of the earlier unit. Model releases come about every two years with major changes about every four years. The Minelab GPX 4500 was extremely popular and the next model release was delayed to the point that two models came out. The Minelab 4800 was intended as the next release, but before it hit the market developer Bruce Candy came up with a couple new refinements different enough to warrant yet another model, the GPX 5000. The 4800 therefore became a sort of "non-model" as most dealers and users focused on the GPX 5000 as the new top-of-the line detector. The main change is a wealth of new timings allowing the GPX 5000 to get optimum performance in many varied ground conditions. The new Fine Gold timing in particular offers the ability to pull gold out of ironstone hot rocks that previous models missed. Minelab SD2200v2 pulse induction (PI) metal detector I disagree with those that say you can get more depth on large gold from earlier SD units than from the latest models. Having used all the models the largest improvement I've seen over time is vast improvements in threshold stability and the ability to adjust for more varied circumstances. It may be that in a particular location an SD will do just as well as a GPX. But not where I hunt. My SD units all had the famous Minelab "warble" whereby the threshold constantly wavered. This meant that small nuggets or very deep larger nuggets had to give enough of a signal to break through the waver. A far cry from listening to a rock solid threshold for the faintest whisper or "break" in the threshold. You can get just such a rock solid threshold with the GPX units. It is not that the GPX goes deeper, it is that you can hear nuggets you would miss with an SD as they could not be discerned as clear signals. More important on my ground was that my SD units simply could not tune out the intense magnetic basalt cobbles we have to contend with. The cobbles give a faint gold hit. So you either dug them all (impossible) or simply ignored the faint signals. But some of them were small nuggets or very deep larger nuggets. When the GPX arrived at my property I saw so many more small nuggets and deeper large nuggets come out of areas well hunted to the point of being "hunted out" that it was obvious the GPX had a significant edge. I'm not talking a nugget or two - I'm talking pounds of gold. The new GPX timings can allow for a clean solid threshold in areas where that was impossible with earlier units. Those that do not hunt such locations do not see the value in a GPX. Those that do know what I'm talking about. There is no way I'd go back to using an earlier model than the GPX-5000 by choice. Minelab GPX 5000 - pulse induction metal detector technology refined It should be noted is there are quite a few people modifying older SD units to get better performance on par with later units, and I'll admit these modified units are a wild card. Some swear by them and I'm not going to doubt them. But modifying older detectors is beyond where most people want to go so I think there is little doubt these units will only see use by a certain hardcore group of knowledgeable detectorists. The GPX 5000 has refined the platform to the point where realistically it is hard to think of ways the unit can be improved from a detecting standpoint. The only obvious deficiency is the ferrous discrimination system. While it does have its uses the ferrous discrimination on the Minelab PI detectors is notoriously unreliable and only to be used when absolutely necessary. Its use will inevitably cause gold nuggets to be left in the ground, misidentified as iron or steel. This area has been so resistant to improvement, however, that I look more for advances in the physical package as my most desired area for improvement. The general control box and rod design with backpack mounted battery has not changed since the original SD2000. Development of a GPX type detector housed in a package more reminiscent of the new Minelab CTX 3030 would be a major advance in the usefulness of the lineup with no actual change in performance aspects of the electronics. It has been well over two years since the GPX 5000 was released, and so I do not think it will be too long before we see what Minelab has in store next for nugget hunters. ~ Steve Herschbach Copyright © 2013 Herschbach Enterprises P.S. When I wrote this article in 2013 I had no idea that two more years would pass before we saw what Minelab had up next - the Minelab GPZ 7000. It turned out that Minelab also thought the GPX 5000 had taken the pulse induction as far as it could go, so the GPZ 7000 features new ZVT technology. The biggest surprise for me however was that Minelab may have paid attention to my "GPX in CTX housing" comment above. That may or may not make some people happy! And the GPX 5000? Still in production as the top-of-the-line PI from Minelab!
  10. 1 point
    The secret to the Minelab GPX series is thoroughly understanding the timings and when to use each one. Timings are variations of the basic pulse induction technology at work in the GPX series that gives you far more flexibility than exists in other pulse induction detectors. Unfortunately this extra flexibility also adds complexity, and so it is not unusual that some people may not be using the optimum settings in many cases. It is very important when investing in a Minelab GPX detector to take the time to read the manuals and study until you fully understand what the settings do and how to adjust the detector for the best performance. Otherwise you will not be getting all the potential out of your investment. The chart below shows the timings and what GPX models they are available on along with a general description. The descriptions are from the owners manuals that are available by download at the bottom of the page. In general you should always use timings as near the top of the chart as possible, with the exception of the Salt settings. Those are for alkali flat and salt water beach areas only. Using timings designed for more mineralization than is actually required may result in less depth on desired targets. Imagine the timings as another sort of ground balance setting. Low mineral settings are more powerful than high mineral settings and should be used whenever possible. Some confusion is the result of the timing names. Some people assume the Fine Gold timing is best for fine gold. This does make a sort of sense, but the fact is Fine Gold is just better than other high mineralization timings on smaller gold. In milder ground Sensitive Extra will obtain better results on small shallow gold. It is also very important to know that some timings work better with one coil type or the other. Minelab GPX Timings Chart Little or No Mineralization Coin/Relic (GPX 5000 ONLY) Coin/Relic is for use in lightly mineralized soils including many beaches and loamy soils. It offers maximum detection depth on a range of target sizes, significantly greater than any other timings. However, if the ground is any more than lightly mineralized, the detector may not ground balance properly. On ocean beaches containing significant quantities of black sand, better results may be had by using Normal or Salt settings. Mild Mineralization Sharp (GPX 4500, 4800, 5000) Sharp is similar to Normal but creates a more powerful detection field. It is capable of an improvement in depth, but is more susceptible to interference and will increase the severity of false signals in difficult grounds. This timing is best used in quiet conditions and can work well in combination with Deep Search Mode with a reduced Rx Gain setting. Sharp is an excellent tool for pinpointing faint signals due to the very "sharp" signal response. Sharp will work best with DD coils in most gold field locations. Medium Low Mineralization Sensitive Extra (GPX 4000, 4500, 4800, 5000) This timing may increase the signal from certain hot rocks near the surface, but can actually help smooth out the Threshold in certain ground types, particularly with Double-D coils. In mild ground conditions Sensitive Extra will provide the best signal response on a small, deep target. Medium Mineralization Normal (GPX 4000, 4500, 4800, 5000) Normal gives you the best performance on a wide range of soil conditions, and it will provide the best depth on a wide variety of target sizes. It works particularly well with the supplied 11" DD search coil for general detecting. You should always use Normal in new areas where you are unsure of the soil mineralization and the depth of targets. Medium High Mineralization Salt Coarse (GPX 4000, 4500, 4800) The effect of alkaline salt mineralization is vastly different to the effect of ironstone and mineralized clays. Normal should be tried first in these areas, but if the Threshold is too unstable then better performance will be obtained in Salt-Coarse. Using the Salt-Coarse timing may result in a loss in signal response to smaller targets. However, the response on larger items remains relatively unaffected and ground noise is usually minimized. Medium High Mineralization Salt/Gold (GPX 5000 ONLY) Provides the best signal response on small to large gold in salt saturated and mineralized ground conditions. It should work well on dry inland salt lakes, high salt concentrated goldfields, and mineralized saltwater beaches. Extremely salt saturated soils may still need to be searched with the coil switch in Cancel (using a Double D coil). High Mineralization Fine Gold (GPX 5000 ONLY) Fine Gold is sensitive to smaller targets in highly mineralized ground. It provides a sharper signal on small gold compared to Enhance, and improves the detectability of rough/flaky gold and specimens, while ignoring most hot rock signals and false ground noises. Shallow, highly mineralized ground where gold has been found previously should be re-examined with Fine Gold, and best results will be had by using the optional 8” and 11” Commander Monoloop coils. Note: Sensitive Extra will provide superior results on small gold in milder ground. Very High Mineralization Enhance (GPX 4500, 4800, Improved in GPX 5000) Runs quietly in most heavily mineralized, variable and "hot rock" infested grounds using a monoloop coil. It is more sensitive and detects deeper than Sensitive Smooth but can be slightly more affected by severe ground mineralization. Severe Mineralization Sensitive Smooth (GPX 4000, 4500, 5000) Sensitive Smooth is optimized for an improved response on smaller, shallow nuggets in severe soils. There is a loss of depth on bigger targets; so you should not use this setting when seeking out large, deep nuggets. Sensitive Smooth is best suited for use with monoloop coils in difficult soils. It eliminates most false signals from hot rocks, and ground mineralization, whilst retaining excellent sensitivity to small targets. The example below shows three common timings and where they should be used. It also highlights why using the wrong timing for the conditions can result in missed targets. Minelab Mineralization and Timing Example The following chart illustrates the procedure for finding the correct timing for each situation. In general, always start with the Normal timing. If the detector is stable and quiet, try timings on the left - Sensitive Extra, Sharp, or in rare cases, Coin/Relic. If ground noise or hot rocks present problems in Normal, then try timings on the right - Fine Gold, Enhance, or Sensitive Smooth. Salt settings should generally only be used on alkali ground (salt flats) or salt water beaches, but may have applications in other ground. The goal is always to find the most powerful setting that allows for stable operation. Each timing can be adjusted within certain parameters, primarily through the use of the Gain and Stabilizer settings. Adjusting for a lower Gain, for example, may be preferable to going to a less powerful timing. Minelab GPX Timing Selection Chart - Click on image for larger version Finally, each timing may work best with a certain type of coil (DD or Mono) and the timings have varying level of resistance to Electro Magnetic Interference (EMI). The matrix below attempts to show which timings offers which benefits and strengths/weaknesses. Minelab Timing Coil EMI Matrix - Click on image for larger version The simple chart below can be printed out and taped or glued on your detector shaft as a reminder in the field as to which timing may be best. Click on the image to download a large version. Minelab Timing Decal - Click on image for larger version Minelab GPX 4800/5000 Instruction Manual Download Here Minelab GPX Series Quick Start Guide Download Here Minelab GPX 4800/5000 Product Brochure Download Here Minelab Commander Coil Brochure Download Here Minelab GPX 4500 Instruction Manual Download Here Minelab GPX 4000 Instruction Manual Download Here ~ Steve Herschbach Copyright © 2011 Herschbach Enterprises
  11. 1 point
    The Minelab Eureka Gold was introduced in 1998 and was discontinued in 2017 after a 20 year run. The Eureka Gold has been replaced by the new Minelab Gold Monster 1000. The Minelab Eureka Gold for a long time was the only nugget detector that allowed you to change frequencies with the flick of a switch; 6.4, 20, and 60 kHz, all using the same coil, unlike the Minelab X-Terra units. This made the Eureka Gold one of the most versatile VLF gold prospecting detectors available for handling different ground conditions. The Eureka Gold 20 kHz mode is used for most detecting for great all-around performance. The 60 kHz mode is used in low mineral soil looking for extra small nuggets. The 6.4 kHz mode is used in extreme mineralized soil that would overwhelm most VLF detectors. The Eureka Gold is a good choice for someone hunting areas with widely varying mineral conditions. Weight including rechargeable battery pack 5.3 lbs. The control box may be chest or hip mounted removing most of that weight from the operators arm. It comes stock with a 5" x 10" elliptical DD coil. Four accessory coils are available for the Eureka (Minelab and Coiltek). The Eureka Gold with its three selectable frequencies will handle a wider range of ground conditions than most other VLF detectors. For a 60 kHz detector, it lacks the edge of the Gold Bug 2 or GMT when it comes to the smallest nuggets. This is because the 60 kHz mode is not the native operating frequency of the Eureka Gold but a harmonic offset of the main frequency. The Gold Bug 2 and GMT are dedicated single frequency units designed specifically around their respective operating frequencies. The best setting on the Eureka Gold appears to me to be the 20 kHz mode, as the detector seems optimized for this frequency. You will generally lose depth in the 60 kHz mode and so this mode should only be used for small shallow gold. The 6.4 kHz mode on the other hand is more of a fallback frequency only for situations where the 20 khz mode is proving ineffective due to hot rocks of ground interference. 6.4 kHz is simply too low a frequency to be effective on small gold nuggets but can help penetrate highly mineralized ground to find larger gold nuggets. Minelab Eureka Gold prospecting metal detector I used the Minelab Eureka Gold and it's predecessors, the XT 18000 and XT 17000 as well as the American Gold Striker. My favorite of the three was the XT 17000 which ran at 6.4 kHz and 32 khz. The 32 khz may seem quite high for the time, but it is a low gain 32 khz and so ran quite well in mineralized ground. I was in Alaska at the time however and low mineral ground and small gold is the norm. Neither the XT 18000 nor the Eureka Gold impressed me much as their 60 kHz frequency was no match for the 71 kHz Fisher Gold Bug 2 or even the 50 khz White's Goldmasters of the time. Those detectors did better for me in the areas south of Anchorage, Alaska that were my stomping grounds for many years. The ferrous discrimination on the Eureka also seemed less reliable than that available on those detectors. The bottom line is that while I used them enough to get familiar with them and find a little gold, they did not suit my particular ground and gold as well as some other detectors. Still, I always recognized that and acknowledged that the Minelabs were a better choice for highly mineralized ground, especially variable ground where its ground tracking shines. The Minelab Eureka Gold played a part in gold rush history. Around the turn of the century new gold rushes were igniting in several third world countries, driven by the discovery of goldfields amenable to metal detecting in those countries. Certain models would be seized on by the locals as being the only thing that would work. The Minelab Eureka Gold enjoyed this status for some time in Mongolia, with all available units worldwide being sought out and shipped to Mongolia, often at exorbitant prices. The rush eventually subsided but probably had something to do with the Eureka Gold being on the market for as long as it was. The Eureka is a good detector, but lighter and less expensive detectors will do just as well for most people. The weight and high price made the Eureka hard to recommend in later years. Now that it has been discontinued Minelab will continue to service existing units for at least seven more years (until 2023-2024). Steve with Minelab XT 17000 in early 1990's Regarding used models. The XT 17000 and XT 18000 both came with rechargeable battery packs before the battery technology was really up to it. Those old battery packs had very limited lives and any still in existence are probably bad. A strange little adapter was available to convert the XT 17000 and XT 18000 to AA battery use, but those were rare and hard to find. If you ever shop a used Minelab XT 17000 or XT 18000 be sure to investigate the battery situation. The Eureka Gold also came with a rechargeable battery pack, but a AA battery holder option was widely available. Again, the older rechargeable battery packs are not likely to have much life in them, so rounding up the AA battery holder is important if looking for a used Eureka Gold. ~ Steve Herschbach Copyright © 2018 Herschbach Enterprises Official Minelab Eureka Gold Page Minelab Eureka Gold Instruction Manual Note On Differences Between Early Minelab VLFs Minelab Metal Detector Forum Minelab Eureka Gold Technical Specifications* Internet Price $1049.00 (Last price before discontinued in 2017) Technology Induction Balance (IB) Frequency 6.4, 20, & 60 kHz Autotune Mode(s) Preset Slow Autotune Ground Rejection Fixed, Fast & Slow Automatic Ground Tracking Soil Adjust No Discrimination Variable Iron Reject Level Volume Control Yes Threshold Control Yes Tone Adjust Yes Audio Boost Yes Frequency Offset No (Except for three main frequencies) Pinpoint Mode No Audio Output 1/4" headphone socket & speaker Hip Mount Yes Standard Coil(s) 10" x 5" DD Optional Search Coils Several accessory coils available Battery Rechargeable Operating Time Up to 20 hours Weight 5.3 pounds Additional Technology Change frequency with the flip of a switch! Comes with hip mount bag. Notes Discontinued in 2017 *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.
  12. 1 point
    The Minelab Gold Monster 1000 was introduced in 2017 and is still in production. The GM1000 was created as a relatively inexpensive, easy to operate, high performance metal detector. The Gold Monster 1000 is designed specifically for gold prospecting but may have applications such as micro jewelry detecting. At 45 kHz with both automatic ground tracking and automatic sensitivity settings, the Minelab Gold Monster 1000 is not only very sensitive to small gold but it is relatively easy for beginning detectorists to use. I am fortunate to have been involved in the testing of the new Minelab Gold Monster 1000 prior to its release. One benefit is that I have seen the questions that others have posed about the detector, and now I can answer a few of them. When I use new detectors I always have a goal in mind. I am not trying to pick the detector apart for what it cannot do. Instead, I believe most well designed detectors have something they excel at. My goal is to determine how to use a new detector for maximum benefit. The best way to make that happen is to use the detector in the way it was intended to be used, instead of trying to force it to be something it is not. The key is to be realistic. The Gold Monster 1000 is sold as an entry level single frequency metal detector. Expecting it to outperform detectors costing many times its price is unrealistic. Engineers face a very important choice when designing a single frequency metal detector, especially as regards gold prospecting. What frequency should the detector run at? That choice determines nearly everything else about the detector. In general, low frequencies below 20 kHz handle mineralized ground better, and offer good performance on larger gold nuggets. Higher frequencies over 20 kHz enhance the sensitivity to small gold nuggets, but unfortunately ground handling suffers. The number one question I see asked on the internet is how the Gold Monster stacks up as compared to this detector or that detector. Minelab has actually tried to answer that question directly via the following illustration: Minelab Gold Monster Frequency Range Compared The majority of the single frequency nugget detectors on the market today operate at or near 18 kHz. These detectors handle ground relatively well for non-PI detectors, and have good sensitivity on gram size and larger gold nuggets. They can detector smaller gold, but the smallest gold is not where they excel and the chart attempts to illustrate that. Other single frequency detectors running as high as 71 kHz have superb sensitivity to the smallest gold nuggets, but tend to suffer when it comes to depth on larger gold in highly mineralized ground. Again, the chart attempts to illustrate this fact. The Minelab Gold Monster 1000 engineers decided to concentrate on a frequency that offered the best attributes of the lower and higher frequency extremes. The goal was to design a machine that would attempt to acquire in a single pass the bulk of the gold that machines operating at either extreme could recover if operated together – and yet do it with just one detector operating as efficiently as possible. The catch is that the Gold Monster is still a single frequency detector and it cannot possibly capture 100% of the gold that two detectors operating separately at two vastly different frequencies can capture. If you study the illustration carefully, you will see there is still some gold the 18 kHz detector will do better on, and some gold the 71 kHz detector will do better on. Minelab is not claiming to be able to outperform every other detector under all other circumstances. The goal here is to capture as much of the obtainable gold as is possible with a single detector operating in the most efficient manner possible. Minelab Gold Monster 1000 nugget prospecting detector I have mentioned efficiency because there is more that goes into designing a gold prospecting detector than just the operating frequency. This is where Minelab is attempting to not only make a wise choice in the operating frequency, but to extend the efficiency of that frequency by optimizing the other parameters. First, electrical interference is detected and automatically rejected as much as possible when the detector is first turned on. This helps alleviate interference that could result in less than optimum performance. A great deal of effort has been made into designing a sensitivity control that offers the ability not only to manually tune the detector but to deliver excellent results automatically. The automatic operation is important in ground that varies dramatically from place to place in such a fashion that it becomes difficult – inefficient – to constantly be readjusting the machine manually to retain the best overall performance level. Novices in particular tend to set and forget the sensitivity, leading to a situation where the detector could be running better if the control were optimized more often. The crowning glory of the Minelab Gold Monster 1000 however is the automatic ground tracking system. The 45 kHz frequency is considered to be a high operating frequency, and as such it is subject to possible issues from highly mineralized ground and hot rocks. Manual tuning detectors can have great difficulty dealing with these problems… here is that word again… efficiently. The operator must be on top of and constantly adjusting the machine manually. It is very easy for the operator to be out of sync with the ground conditions and operating at less than optimum performance. At high frequencies having the proper ground balance is extremely critical. Manual ground balance versus automatic ground tracking I will admit I have always tended to distrust automatic ground tracking systems. The theory is they can track out good signals resulting in missed targets. The reality however is the risks entailed by not being properly ground balanced are even greater, especially for novices. The illustration below attempts to show what happens when the operator of a manually tuned detector falls out of sync with changing ground conditions, and then “catches up’ by retuning the machine. The automatic tracking or continuous ground balancing detector however maintains optimum conditions at all times. Even given this evidence in the past however I was a skeptic, and always preferred to manually adjust my detector ground balance controls. That is until I obtained first a Minelab SDC 2300 and then a GPZ 7000 detector. The SDC forced me to use automatic ground balance by offering no other option. A surprising thing happened – I liked it! It worked and it worked extremely well, so much so that when I got my GPZ 7000 it also remains in automatic ground balance mode. The fact is that Minelab has always been a leading developer of automatic ground balancing systems, and I do not think it is being unreasonable to state that they may have the very best ground tracking systems available. The company really has had no choice being based in Australia and developing machines for ground conditions considered to be among the worst in the world. Can the Minelab Gold Monster 1000 go up against the hottest high frequency detectors made and hold its own? Yes. I have personally used the Gold Monster with its 5” coil to easily find nuggets (flakes?) weighing under a grain. Not grams, grains - there are 480 grains per Troy ounce. Remember however that even Minelab in that first chart is telling you that a machine tuned specifically at a much higher frequency will have an edge on at least some tiny gold nuggets. Eleven small nuggets 14.9 grains total, largest 4.4 grains - Smallest at bottom 0.6 grain and 0.3 grain The difference and the serious advantage I believe with the Gold Monster 1000 is in the combination of the superior Minelab ground tracking system and the automatic sensitivity system, designed specifically for the GM1000. In all but the mildest ground operators will find that the Gold Monster is a much more efficient detector that allows more ground to be covered while keeping the machine tuned for the best performance possible. My advice to the old pros that get their hands on the GM1000 is that rather than try and force the machine into operating like your favorite manually tuned machine, seek out instead conditions where that machine struggles. Then trust in the Minelab automatic ground balancing system to compensate for and deliver superior performance under those conditions. Use manual more for targeting specific small areas. Case in point, I took the Gold Monster to a location where hot rocks had given my GPZ 7000 some difficulty. Much to my surprise the Monster was able to automatically compensate for and allow me to operate in those hot rocks and find a couple tiny nuggets too small for the GPZ 7000 to find. The machine was far smoother and I was able to cover ground far more efficiently with automatic ground balance. I followed this up with a visit to a location with wet alkali ground where a high frequency machine would normally fail. I struggled with manual sensitivity for a bit, then threw in the towel and went to the highest Auto+ sensitivity setting. The machine quieted right down and I found a nice little nugget shortly thereafter. Nugget embedded in lump of dirt If the ground allows you can certainly use manual ground balancing to get that hot edge on tiny gold nuggets. The Gold Monster 1000 lacks a standard threshold, but it is easy to set up a pseudo threshold by advancing the sensitivity to where the machine produces some light feedback from the ground. Those who like a threshold can run it this way – others may wish to back down just one notch for silent operation. Old timers like me rebel at the thought of running without a threshold but with the GM1000 it works. The normal reason for running a threshold is to be sure the detector does not fall out of proper ground balance. Here however you can put a superb automatic ground balance to work for you, eliminating that concern. For the very worst conditions, the automatic sensitivity system can augment the automatic ground tracking to allow for efficient ground coverage under conditions that will bring other detectors in this class to a crawl, if not a complete stop. Frankly, if you can’t get the Gold Monster to handle the ground, it is time for a Minelab PI detector or a GPZ 7000. To sum up, I do not want to leave you with the impression that the Gold Monster is the be all and end all of single frequency nugget detectors, and that it will under all circumstances get better performance on every single gold nugget than other single frequency detectors. That is not possible given the limitations imposed by having to choose a single operating frequency. I do believe however that the engineers at Minelab have come as close to this as is possible. The real secret to getting good results with the Minelab Gold Monster 1000 versus the competition will be in leveraging its superb ground handling capability to get the best overall gold nugget performance possible from a single frequency detector. ~ Steve Herschbach Copyright © 2017 Herschbach Enterprises Official Minelab Gold Monster 1000 Page Minelab GM1000 Color Product Brochure Gold Monster 1000 Getting Started Guide Forum Threads Tagged "minelab gold monster" Minelab Metal Detectors Forum Jonathan Porter On Mastering The Minelab Gold Monster Understanding The Sensitivity Control On The Gold Monster 1000 Reports Of GM1000 5" Coil Touch Sensitivity My GM1000 Methodology - Manual Versus Auto Sensitivity Minelab Gold Monster 1000 Technical Specifications* Internet Price $849.00 Technology Induction Balance (IB) Transmit Frequency 45 kHz Autotune Mode(s) Pre-Set Slow Motion Ground Rejection Automatic Ground Tracking Soil Adjust No Discrimination Iron Reject Mode plus Visual Indicator Volume Control Yes 1 - 6 Threshold Control No Tone Adjust No Audio Boost Yes (Always On) Frequency Offset Yes - Automatic On Power Up Pinpoint Mode No Audio Output Speaker & 1/8" Headphone Socket - Headphones Included Hip Mount No Standard Coil(s) 10" x 6" elliptical DD & 5" round DD Optional Search Coils N/A Battery Li-Ion Rechargeable Included, 8 AA Optional Operating Time 20 Hours Weight 3.2 lbs. (with rechargeable battery and 10" coil) Additional Technology The GM1000 automatic sensitivity setting is a feature not seen before in prospecting detectors. Notes Unique rod mounting system allows use of broomstick or other items as a rod. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart.
  13. 1 point
    I've been a longtime fan of the White's Goldmaster series, but I was really annoyed when White's put the machine into the XLT packaging. I like to keep weight off my arm, but more importantly I work some very steep hills where putting a machine down can be a problem. The unit will simply roll to the bottom of the hill. I also work in muddy conditions a lot and so I do not want to set my detector down in the soup. A little history. Prior to 1990 the White's Goldmaster was a simple T/R detector housed in a blue aluminum box. Those old obsolete models should be avoided by all but collectors because they could not ground balance. Around 1990 White's introduced the Goldmaster II, which featured a new black paint scheme. These black box models since 1990 are all quite capable 50 kHz nugget hunting detectors. The Goldmaster II used a S rod design that allowed the control box to be mounted in several locations on the rod, plus removed completely and either chest or hip mounted. This design was popular with prospectors. I still remember clearly the huge fuss when White's introduced the Goldmaster 4/B around 1998 and put it in the same one piece control box as was used in White's coin detecting models. This was no doubt partly a cost saving measure but also to accommodate a much larger circuit board as the Goldmaster series made the move from analog to digital. The Goldmaster 4/B was an hybrid analog/digital design that preceded the microprocessor based White's Goldmaster GMT. The dealer network raised a fuss and Jimmy Sierra in particular was incensed by the design change. He prevailed on White's to make a run of "chest mount only" models that basically took the handle and pod assembly and stuck it in the middle of the control box. A cumbersome design if there ever was one. It was also basically kept secret from anyone but Jimmy's dealers and so the chest mount only model is a rare Goldmaster indeed. This move coincided with Fisher introducing the Gold Bug 2, which at 71 kHz was hotter than the 50 kHz Goldmasters, plus had the hip and chest mount options with an even more compact design than the Goldmasters. Goldmaster sales plummeted and the Gold Bug 2 took over. The very unpopular Goldmaster 4/B was replaced by the 48 kHz GMT, a totally new microprocessor design. White's Goldmaster 3 (GM3) - last analog model, last with removeable control box Starting about 1990 the sequence was: White's Goldmaster II (1990) - new 50 kHz model, on S rod with removeable control box. White's Goldmaster V/SAT (1996) - added Variable Self Adjusting Threshold (V/SAT) control, on S rod with removeable control box. White's Goldmaster 3 (1997) - Added frequency offset, boost options, three piece rod standard (optional in previous two piece models), on S rod with removeable control box. Widely considered the best analog Goldmaster. White's Goldmaster 4/B (1998) - Added meter on a pod for iron discrimination, non-removable coin detecting type box design. White's GMT (2000) - Completely new 48 kHz microprocessor model, non-removable coin detecting type box design. White's Goldmaster 4/B with the new "coin detecting" control box design I really wanted a new White's GMT. The automatic ground balance and LCD iron readout are very good. So I thought about what I might do to get what I wanted. A GMT to chest or hip mount. White's makes a chest mount version, but it has the darn handle/pod sticking out the front where it blocks vision and is prone to getting hit while digging. And for hip mounting it bumps into things. White's Jimmy Sierra GMT chest mount I went ahead and bought the chest mount version, but the following conversion can be applied to the standard model as well. I went with the Jimmy Sierra special chest mount model as a starting place since the rod assembly is already a separate item. 2011 Update: White's does not make their chest mount version any longer. First step... take it apart! Here is the unit in parts, with a close up of the main board: White's GMT components disassembled White's GMT circuit board White's GMT pod contents The main board is clearly marked with what plugs where. Nice for reassembly. I took the pod apart, and ground the touchpad mounting down to just the pad itself as it was glued on too well to pry off. The LCD plugs into a mini circuit board in the pod, along with the trigger switch. Then a long cable runs through the handle and to a plug in the center of the main board. I wanted to chest mount the unit with the coil cable and headphones running out the right side. This meant the LCD would have to be mounted on one side. That particular side does not have enough room to flush mount the LCD into the case, so I decided to cut a hole in that side and mount the LCD on the outside of the case. This meant the mini circuit board would have to be mounted inside the case lid where the speaker resides. I am a headphones guy anyway, so out came the speaker. You could flush mount the LCD on the other side and retain the speaker, but then the coil cable will exit on the left. Good for lefties, however! You might even be able to do it the way I did and keep the speaker, but my fingers are not the most adept, and I figured I could use the extra work room. Mounting the pod circuit board The picture above shows the positioning of the mini circuit board inside the lid. The white ribbon cable runs out to the LCD. The green ribbon cable runs out through a hole I cut in the lid to the touchpad. I glued the touchpad on the outside of the case. More on that in a minute. The wires run to the new trigger switch location. I mounted the board on short spacer posts. Mounting the touchpad and LCD display The picture above shows you where we are heading. The LCD is mounted outside the case. The LCD was mounted using the hardware that originally mounted it to the mini circuit board. A D-Ring has been repositioned to the left. The touchpad is glued down partially covering the speaker holes. The rectangular hole in the case was left after removing the handle. You can see the new trigger switch location. I'm going to replace this switch with one of the rubber capped types. The touchpad covered the battery check/audio boost switch, so it was relocated to a position below the trigger switch. I had to lengthen the wires to do this, the only soldering involved. As I look down at the LCD, I can easily operate the switches and pad with my left hand. The switches are set so I can push down on them to activate the battery check or iron id accumulate mode. Relocated touchpad I cut an aluminum faceplate to cover all the leftover holes and glued it in place. Painted it all black so it would look halfway ok. If I had it to do over again, I would make the faceplate at the same time as I was mounting the touchpad. It was hard to make the faceplate after the fact, and I had to dismount and remount the mini circuit board to drill the bolts mounting it through the faceplate. Better to glue down the faceplate and pad as a unit, THEN drill the holes for mounting the mini circuit board. Relocated LCD display This turned out to be the hardest part. I originally figured I would be able to find some kind of clear plastic box to glue over the LCD to protect it. I cruised aisles in Lowes, Kmart, and Fred Meyer for hours looking for any kind of little box I could cut down and use. Finally I decided to make one. I got a piece of oak trim about 3/8" thick and made a bezel. I found a piece of thin plastic and made a window for it, and glued the window onto the bezel. I cut the original LCD stick-on window (the one that says "% probability of iron") down and glued it in place over my window. Finally, I glued the whole assembly over the LCD. Imagine my surprise when I tested it out after the glue had set up and the LCD was missing half its pixels! I was bummed. I took the case apart and wiggled everything. The unit was working fine, just the LCD was acting funny. Finally I pried my carefully placed cover off and looked the LCD over. No obvious problems. It was still just barely readable, however, so I figured the heck with it, and glued the cover back on. After it set up, I tried it again, and now the LCD was almost totally blank! I was using a glue called E6000 that bonds most anything. I decided that somehow the fumes from the glue had somehow "poisoned" the LCD. So I put a lamp on the unit and blew air in it periodically. And behold, the LCD slowly came back to life! Whew!! I cruised the net looking for info on this weird problem, but never did find anything. GMT conversion chest or hip mount So here is the final product. Actually, as you can see, I took these before I did the trim work. The chest mount is just for show. I need to rig up a full harness. But I'll tell you what... I really liked it. Everything right there where I need it, but well out of harms way. The alternative hip mount setup is better than the original by far, but I liked the chest mount so much I will only use it like this where there is no trash to deal with. I'm still looking for that spot! So there you go. This is not for the faint of heart. It was the first time I had done a mod this extensive, and it was a somewhat scary feeling to be tearing a brand new detector apart. Kiss that warranty goodbye! But now I have a unit I really like that will work well on steep slopes and other odd spots. Not to mention give my arm a break. The GMT is very well balanced, but every ounce counts when you are at it for 10 or 12 hours at a time. A final note. You could leave the pod on the handle and route a longer cable from it up the coil cable and to the control box. But I wanted the pod off the handle entirely, and adding more cables seems like a way to ask for more problems down the road. I know another guy that has now done this mod after seeing mine, and a third is at work on his. Maybe some people going to all this effort will tell White's that their old box design was better. Postscript: After the above post was made I took my new White's GMT chest mount to Ganes Creek, Alaska for a real world nugget hunt. The unit worked as I hoped and then some. Here is a picture of it and the 1.89 ounce gold nugget it found for me! 1.89 Oz nugget found with White's GMT chest mount conversion ~ Steve Herschbach Copyright © 2002 Herschbach Enterprises
  14. 1 point
    I recently treated myself to a metal detecting holiday to the area around Colchester, England. This was a reprise to a trip I made to the UK in 2010 in search of Celtic gold. Gold was not in the equation for that trip, but I did find the oldest coins and artifacts I have ever found.... as in 2000 years older than anything I have found before! Colchester has history reaching back into prehistoric times, and is generally acknowledged as the location of Britain's first city. Celtic tribes were active in the area, leaving behind many Celtic gold coins to be found by modern day detectorists. The Romans were also very active in the area, as were other invaders, leading to finds from many cultures across the centuries. I made a return visit to Colchester in 2018, this time relying heavily on the new Minelab Equinox metal detector as my detector of choice. I also had the opportunity to use the new Minelab Equinox 15" x 12" DD coil while on this trip. Not only did I have a very successful trip, but I got to observe other great finds made by the other detectorists in the group. All in all this was a very exciting metal detecting experience that I enjoyed thoroughly. The links below outline both my own experiences and the same trip told from the perspective of another person on the same adventure. Steve's 2018 UK Adventure by Steve Herschbach My UK Trip .... Double Ancient Gold! by Ill Digger Steve Herschbach finds ancient UK gold!
  15. 1 point
    White's MXT Engineering Guide David E. Johnson, engineering consultant This Engineering Guide is written to provide dealers and customers greater insight into what kind of product the MXT is, from an engineering perspective. It does not attempt to provide complete information on the features and use of the MXT: for that, please consult the MXT user's manual. A BIT OF HISTORY In January 1998, White's decided to develop a true multipurpose metal detector, with the kind of sensitivity it takes to be a real gold prospecting machine, and with computerized ground tracking for ease of use. White's in-house engineering staff was tied up on the project which eventually became the DFX. Therefore, in February White's asked me if I might be interested in taking on a new protect. I had a good track record on gold machines so it seemed like a good fit. I agreed. A month later at a dealer seminar in Sacramento, California, Jimmy Sierra announced the project, and said if the engineer didn't deliver, the engineer would have to go into hiding in Mexico. I was sitting in the back. We ran into one problem after another along the way. Jimmy, good chap that he is, didn't sic the thugs on me, though there were periods he was frustrated enough that the thought must have run through his mind. Although the project took longer than we expected we got two products out of it - the GMT and the MXT. The first major hurdle was to get the basic circuit and software system running, with a first class ground tracking system. The system architecture was totally new, not a revision of the existing Goldmasters. In early spring of 1999 an ugly prototype was up and swinging, and Larry Sallee became involved in field-testing. By April the ground tracking system was working so well that since that time very few changes have been needed. At that point we knew we had a solid foundation, so work began on the display, discrimination and target ID features. During the fall of 1999, we decided to tackle the problem of desert heat head-on. A lot of gold prospecting is done in desert heat in full sun. I set up a crude but effective, thermal engineering laboratory, measuring the temperatures reached inside housings of various configurations and colors in full sun. Then began the task of finding an LCD, which would handle the heat. Because the LCD display is an important feature of the MXT, we revisited the whole issue of display. The manufacturers of LCD display had expanded their product offerings. We found a larger one, and changed the mechanical design of the MXT to accommodate it. A FSTN 0160 F was selected, (there are more to choose from nowadays, so we used a bigger one than the GMT in the MXT.) In early 2000, White's decided to bring out a new Goldmaster based on the work that had already been done, while development of the multipurpose unit continued. So we modified a prototype to work with the Goldmaster search coil at about 50 kHz, and you know the rest of that story - the GMT "tracking Goldmaster" was introduced in early spring of 2001. As work continued on what eventually came to be called the "MXT", we spent a lot of time on the discrimination and target ID system. There are many different ways to do discrimination and ID, each with its own advantages and disadvantages, which aren't always known until you've had the thing in the field being tested for a while. A lot of work got thrown out as we found deficiencies in what had already been done, and discovered ways to improve things. As the project got closer to production, more people became involved with it, and offered their own ideas to improve it. The reason the MXT is as good as it is, is because of that long process of field-testing and revisions. While the MXT was still under development, the DFX was introduced. The MXT design was then revised to run at about 14 kHz in order to take advantage of the DFX loops. When it was finally time to call it "good" in June 2002, the MXT went into production quickly and smoothly. CIRCUIT DESIGN The circuitry of the MXT is almost identical to the GMT, which has already been on the market for a year and a half and has proven to be rock-solid. The GMT's circuitry broke a lot of new ground. It uses a reactive impedance transformation network to boost transmitter voltage for higher sensitivity. It uses an active transmitter regulator to keep transmitter voltage constant even when the search coil is moved over black sand that would blow an unregulated machine off the air. The differentiator-filter circuits usually found in metal detectors are eliminated. Those functions are now done in software, which is made possible by the use of a high-precision 16-bit A/D converter used in a way that makes it equivalent to 17 1/2 bits. All the controls are digitized, their function actually performed via software rather than in circuitry. The audio system is temperature compensated in software to eliminate threshold drift. For the MXT, we chose an operating frequency of 13.889 kHz. This is high enough to give good sensitivity to gold, low enough to give good target ID on typical coin, trash, and relic targets, electrically compatible with search coils derived from the DFX and halfway in between power line harmonics to minimize electrical interference. SOFTWARE The MXT uses a Microchip PIC 16C76 micro controller, chosen for its low power consumption and its set of features, which was a good match for this application. The software that runs in this chip is based on that in the GMT, but almost all of it is new or has major revisions, except the device drivers and the ground tracking system. Much of the new software is for target ID and discrimination, features that were not present in the GMT. Even the iron probability and VSAT systems in the MXT are new, despite their apparent similarity to the GMT. The MXT/GMT does as much of the signal processing as possible in software rather than in circuitry, using what we call "low-speed DSP architecture". The demodulated signals are digitized, and processed and analyzed in software. Control positions are also digitized and made part of the data in software. The desired audio signal is computed, and then converted back to voltage using a 12-bit D/A converter. The circuit board communicates with the LCD and trigger switch in the "pod" via a custom-designed serial link. In the MXT the filters, differentiators, and sample-and-hold functions are performed in software, not in circuitry. This eliminates the problems of channel mismatch and drift, which are often encountered in such circuits. The discrimination system is a second derivative ("two-filter'') design for quick response over a broad range of sweep speeds. The analysis system for determining what kind of target is present has special features which reduce interference from ground minerals, and which automatically scale target ID confidence according to the mineralization level. GROUND TRACKING SYSTEM The ground tracking system comprises two subsystems: a ground analysis engine, and a ground balancing system. The ground analysis engine continuously monitors incoming signals to determine whether the signals probably represent ground, or may be something else such as metal targets or electrical interference. Signals, which seem to be ground only, are put into a data analysis subsystem, which analyzes the data for a number of variables. Then it can be determined what the balance point of the ground matrix is and how fast that balance point is changing. It'd be nice to describe all this in detail but we'd rather not teach our competitors how to do it. The ground balance system does the actual balancing of the signals, doing in software somewhat the same job as a ground balance knob does on a manually balanced machine. When the TRAC toggle is in the "ground" or "salt" positions, the ground balancing system follows the output of the ground analysis engine. When the toggle is in the center "lock" position, the ground balance subsystem stops following the output of the ground analysis engine, which is still chugging away in the background continuing to gather ground data. The ground analysis engine can do a good job of telling the difference between ground matrix and anomalies such as hot rocks and metal targets. In order to tell the difference, it has to see matrix by itself during at least part of the sweep. When you're not in "lock", keep your sweeps broad, and don't loiter over the top of a target when checking it out. Otherwise the analysis engine may lose the ground matrix and start tracking into the target. However, if the target is strong enough to register on the VDI readout, the target ID system will tell the analysis engine to halt, allowing you to check the target without tracking into it. In all three programs, pulling the trigger to pinpoint a target also tells the ground analysis engine to halt. Some users will hunt with the tracking toggle in "lock", occasionally updating the ground balance by flipping into "ground" or "salt" momentarily when they start hearing too much ground noise. The resolution of the ground balancing system is 1 part in 4,000, and most of that resolution is concentrated in the range where high mineralization occurs. Therefore, the individual resolution steps are below audibility under all conditions. THE VSAT SYSTEM The VSAT system on the MXT is similar in a general way to the one on the GMT. The VSAT function is done entirely in software. Up to about 2/3 rotation, the SAT is of the conventional (first derivative or auto tune) kind, giving a "zip" sound on a nugget and a "boing" sound on a negative hot rock (cold rock). As you approach maximum rotation, the MXT goes into "HyperSAT". HyperSAT is a completely different type of SAT system with different sounds and target responses. The background threshold sound is a little rattier, but nuggets are crisper, the ground is quieter, and negative hot rocks vanish when you slow down your sweep. For all but the most experienced users whose ears are calibrated to hear every little nuance of a regular SAT signal, HyperSAT gives more effective depth in bad ground than normal SAT. THE DISCRIMINATION CONTROL The discrimination control does pretty much what you'd expect. Unlike some discriminators, when the control is at zero, there is no discrimination at all - i.e., "true zero discrimination" - and all targets will be detected. Below about 2, the discrimination is based on a combination of both signal phase, and signal strength relative to the strength of ground mineralization. This feature allows the user to get good rejection of shallow iron with minimal loss of deeper targets. THE GAIN CONTROL The gain control knob controls two things at once: the preamp circuit gain, and the software gain. The following is a simplified explanation which is not technically correct in all its details, but will serve to give a general picture how the gain control works. As you advance the gain control from 1 to 10, the preamp circuit gain steps through five levels of gain: xl, x2, x4, x8, and x16. On most machines (depending on minor variations in search coil alignment) you can hear a momentary blip as the machine switches from one gain level to the next. The recommended preset (marked by the triangle) corresponds to a preamp gain of x8. In mild ground conditions where there is no electrical interference, you may want to advance the gain control into the crosshatched region. In this region, the signal data in software is multiplied by successively larger numbers, increasing the loudness of the signals. It is somewhat similar to the "audio boost" function found on some other models of metal detectors. It's particularly useful if you're using the speaker rather than headphones and there's a lot of noise from traffic or wind, or if you're demoing the machine to someone else. BASIC SENSITIVITY PERFORMANCE Since this is a multiple-purpose machine, a U.S. Nickel coin is the most appropriate standard test target. With the gain cranked up, and in the absence of electrical interference, a nickel will typically "air test" beyond a foot using the standard 95O search coil. Your actual "air test" distance will depend on your hearing, the sweep speed, what search coil is used, how much electrical interference is present, and how you have the controls set. In comparison to other machines in this price range, the MXT is extremely hot on low-conductivity items. On gold, it's right in there with the more popular gold machines, being especially hot on the larger, deeper nuggets. It will compete with all comers on low-conductivity , relics and on nickels. On high conductivity coins such as quarters and silver dollars, it is still an excellent performing machine, but there are several other products in the same league for sensitivity. GROUND TRACKING PERFORMANCE The ground tracking system is nearly identical to that in the GMT, which is widely regarded as one of the best tracking systems on the market. Compared to most other trackers, the MXT has superior resolution, tracks faster, "jumps" into new ground more quickly, has greater resistance to tracking into targets, and tracks over a wider range of soil conditions. The MXT allows tracking to be inhibited if desired. DISCRIMINATION PERFORMANCE All discriminator designs are compromises. Here's how the discriminator in the MXT stacks up against other machines. AIR TEST "DEPTH": generally well beyond 10 inches, because of high sensitivity, with effective discrimination to within 0-3 inches of the basic air sensitivity of the target. Most discriminators will discriminate in air to within 0-3 inches of the target air depth on most targets, but most don't have the sensitivity of the MXT. QUICKNESS & TARGET SEPARATION: among the best, because of medium-speed second derivative ("two-filters") design. Initial field reports indicate that the MXT's mixed-mode tone system gives indication of adjacent ferrous/nonferrous targets, superior to that obtainable through discrimination. IRON REJECTION: Because of its high sensitivity and a slight preference in the software for not losing questionable targets, it'll be a little chattier than some less sensitive machines. Reducing sensitivity by cutting back on gain, or by reducing the threshold control setting to minimum, will help quiet it down when necessary. DEPTH IN MINERALIZED GROUND: Although the MXT is a two-filter system, it incorporates special techniques which reduce ground interference and which reduce the "chopping & popping" which plague most other two-filter machines. This, together with its high basic sensitivity, makes it an excellent machine from the standpoint of discrimination depth. FAST SWEEPING: Many discriminators tend to lose good target signals, even shallow ones, when quickly sweeping the search coil. The MXT is tolerant of moderate search coil sweeps, that is to say good at both faster and slower search coil paces. SUMMARIZING: The MXT has the responsiveness and sensitivity of a first-rate 2 filter machine, combined with the discrimination accuracy of a first-rate 4-filter machine. TARGET I.D., ETC. With its small medium and large blocks on the target ID screen, the ID system in the MXT bears a superficial resemblance to the "Signagraph" of the Spectrum XLT. It should be realized that the traditional White's Signagraph system is typically (optionally) set to accumulate data over multiple passes over a target, and displays the accumulated average. The MXT displays fresh data on each pass and scales the size of the block according to how strong the signal was relative to the ground conditions on that specific pass over the target. The visual ID system on the MXT is fast, easy to read, generally more accurate than the discriminator, and gives a visual indication (via block size) of how reliable the identification is. It is going to change the minds of many beeper enthusiasts who previously thought visual ID to be of little practical use outside typical coin shooting. CASCADE THE CASCADE OF EFFECTS OF GROUND BALANCE SETTING: In order to know what the ground balance setting is; flip momentarily to the gold program if you were in another mode. Electronic ferrite material and most "negative hot rocks" (cold rocks) will usually read in the 75-88 range. Most soils will read somewhat lower. Readings will almost never go below 25 except in salt or moist alkali soils. When readings indicate smaller numbers than 50 you may notice some reduction in sensitivity. Below 35, some rusty iron may give unpredictable responses. Below 25, iron objects may give unpredictable responses and/or may disappear entirely and the sound on nonferrous objects may become slightly more abrupt. MANY THANKS To Kenneth White and Alan Holcombe for having sufficient confidence in me to put food on my table through the good times and the rough times on this project. To Jimmy Sierra for having the patience to argue with me about all the stuff that needed arguing about, for being so passionate about the need for this product, and for being willing to compromise when that's what it took to keep the project moving. To Larry and Sue Sallee, for their personal hospitality and for field testing prototypes. To Keith Zorger, Randy Smith, Mike Brighty who field-tested and helped develop the MXT. To Bob Canaday, for being such a competent technical/engineering liaison, doing a lot of not glorious but necessary work well and managing the project during its sometimes difficult phases. To Rick Maulding, for overseeing the project, for technical contributions to the discriminator and to the salt system, and for committing White's engineering department's finest minds to engineering review during the "slow SAT isn't hot enough" crisis, which led to a major system revision that made the whole machine better. To John Earle and Dan Geyer, for diligently hacking away at problems until they became non-problems. To Steve Howard and Pam Godell of White's. There were other people involved in this project whose contact was primarily or exclusively with White's and not with me. The risk of printing credits is that one may inadvertently omit a name that belongs there; so, if I missed someone whose name belongs on this list, I'm sorry, it was an unintentional oversight. - D.E.J. P/N 621-0468 published 8/2002 by White's Electronics
  16. 1 point
    From original forum post 5/27/2008 updated 2/14/2010, 1/13/2013 and 1/3/2014 The White’s PulseScan TDI is a ground balancing pulse induction (GBPI) metal detector and as a rule these detectors are considered “dig-it-all” type detectors. The TDI, however, has a number of manual controls that can be adjusted to allow for a degree of discrimination not normally found in PI units. Most normal pulse induction (PI) detectors have a monotone audio response on targets. In other words, the soft threshold tone simply increases in volume in relation to the target strength. All target sound more or less the same, the only difference being a stringer or weaker audio response. This makes things real simple - you just dig everything. Ground balancing pulse induction, or GBPI detectors, employ a method of ground rejection that in current models has an audio side effect. Tones are produced in relation to the current ground balance setting. In the case of the Garrett and Minelab models, a dual tone is produced by a single target. Either a high-low tone or a low-high tone, depending on the target and how it relates to the current ground balance setting. The White's TDI has a simpler response on a single target, either a high tone, or a low tone. The targets and the tones they produce fall into two broad categories. In general one category has low conductive items, like aluminum, US nickels, most gold, and small ferrous trash. On the TDI these items produce a high tone. The other category has highly conductive items including clad, copper, and silver coins, silver rings, some large gold rings and very large gold nuggets, and large ferrous items. The ground balance varies depending on the ground itself but usually is around the same as zinc pennies, and therefore these may read in either category. Other settings, such as the pulse delay on the TDI, can also cause items to vary. The following photo shows how the two target categories break down digging around school yard playground equipment. Coins found with GBPI detector Left side high tone targets, right side low tone targets As you can see in the photo the vast majority of targets produce a high tone response. What is lacking at this location is large nails. Large nails will give a low tone response and so would end up with the coins on the right. Still, by digging low tones only, the vast majority of trash targets can be passed up and excellent results had on deep copper and silver coins. The following photo shows what might result digging low tones only in a park setting. Coins and nails detected with PI Low tone only targets The icing on the cake with the TDI is the Target Conductivity switch. Normally you would have to listen to all the tones the detector produces, the vast majority of them being high tone, to pick out the much rarer low tones that would possibly indicate a deep coin. The Target Conductivity switch allows one response or the other to be suppressed, and by selecting for high conductive low tones only, the TDI operates very quietly in very trashy environments. This value of this feature cannot be overstated, and it makes the TDI a secret weapon for pulling coins out of extremely mineralized ground where VLF detectors would fail. The TDI can go even farther, because unlike the Garrett and Minelab models it features a manual ground balance. This means that in milder ground conditions the ground balance control can be purposefully misadjusted to directly affect target tone responses. This method was passed on to through comment from Reg Sniff and George Kinsey so credit goes to them for turning me on to this. The method involves purposefully misadjusting certain controls to get results and I’m not saying these are the best settings per se. I would encourage more experimentation to see what you can coax from the Whites TDI as I have not seen a detector so prone to experimentation and yet with relatively few controls. This is not a VLF detector and so lessons learned with VLF detectors often do not apply, and in fact could get in the way of understanding the TDI. Have an open mind and experiment. I highly recommend the use of a PI pinpointer with the Whites TDI. You need some serious pinpointing power. The DetectorPro Uniprobe units are very good, but you may need to switch the TDI off when employing the Uniprobe pinpointer if the TDI interferes with the Uniprobe. Coiltek makes a 1” probe with switch box that can use the TDI itself as the pinpointer as another option, along with the more common self-contained pinpointers like the Garrett Pro-Pointer. With the unit powered off, set the TDI Gain at 12, Pulse Delay at 10uS, Ground Balance knob at 1.5, GEB switch On, Target Conductivity On, and then turn the unit Power On. Set for a faint Threshold. If you are getting any interference (uneven threshold, warbles, and funny noises) slowly run the Frequency knob through its range seeking the quietest setting. Then flip the Target Conductivity switch to High. The threshold should go extremely smooth. If you get spikes or noises breaking through the normally rock solid threshold you may need to reduce the Gain. But usually at this point the threshold will be so smooth and solid you will find you can reduce it so low as to be barely heard. Now try waving various steel items and coins a few inches under the coil and note the responses. You will see that most steel and iron, aluminum, and bottle caps will not signal. Beyond that, there are three basic responses. First, hold a coin 6-8 inches from the coil. Note the soft, sweet tone, woo, woo. Listen to it over and over, as this is your deep coin signal. Now run a coin or larger steel item within 1 inch of the coil. You will get an overload signal, a strong baaaaawo, baaaaawo. This is the shallow item overload signal. If you are trying a steel or iron item, increase the distance from the coil. Note that at a certain distance it abruptly cuts off. Now try a coin and slowly increase the distance from the coil. It will gradually turn into that sweet coin tone. The way you tell shallow coins from shallow junk is to slowly raise the coil. If the target just cuts off – junk. If it slowly mellows out – dig! OK, let’s go detecting. What follows is the results of an outing using these settings. Listen for that sweet, deep coin sound. Those are the oldies and you main goal. In some hunted out parks this may be about the only signal you get as there are no shallow targets to generate to overload tone. Just go dig coins. Walk around each target and insure it gives a good, clean response from all angles. Be sure and use proper digging practices to leave the ground undamaged. Please protect our hobby. In other places you will get lots of overload signals. If all you care about is deep coins, ignore them. If you want, however, just raise the coil while sweeping, and if the signal cuts off, skip it. If it fades to the deep coin tone, use your pinpointer and there should be a coin within an inch or two of the surface you can just pop out. The Target Conductivity switch can be set too All to investigate questionable targets and to size targets. A pipe buried horizontally will have a high tone its entire length but a low tone at each end. When you walk around these in the High setting you will only hear the low tone and think it is a coin, but they tend to fade in one direction as you walk around them. If the target seems iffy, switch to All and see if you are picking up the end of an elongated iron or steel item. This false positive can occur well off the end of the pipe and so if you dig and nothing is there you may be off the end of a pipe or rebar. This is where a top notch pinpointer comes in handy. The Pulse Delay seems to be most critical, and if you set in much higher than 10uS the ability to ignore iron is lost. But when it is working right the iron rejection is amazing. Try walking up to a garbage can or other large steel item. You will get no signal until you get close enough to overload the unit. Not only does the unit ignore iron, but nearly all aluminum and bottle caps. The only ferrous target I found was a very rusted bottle opener buried vertically in the ground. If flat it is rejected but the TDI does pick it up if held vertically. I never did dig a bottle cap. I did get two aluminum screw tops that gave the shallow overload and that then sounded like shallow coin when the coil was raised. I got one older aluminum screw cap that was not deep or shallow so I checked it out. I also got positives on two copper wires, two chunks of broken heavy aluminum, an aluminum grommet, and a copper screw cap. Coins found with White's TDI Oh yeah, I found 39 coins. Including three silver dimes and three wheaties so they were not all recent drops. That is 39 coins to 10 trash targets using a PI detector in a turf setting. That is a four to one ratio, and when hunting the deepest targets no worse than a VLF. Better yet, the targets that fooled me were not exactly bad targets by deep detecting standards. There was a time I would have said this was impossible with a pulse induction metal detector. I really did feel most of the junk was iffy but I wanted to check as I am learning. Coins sound oh so sweet and when I’m 100% sure it is a coin it almost always is. What else to say? The GB control is in effect the discrimination control. It is all about setting the Pulse Delay, the GB control, and the Target Conductivity switch to get the best balance of depth and iron rejection. The iron rejection tends to be best at low GB settings, and in high mineral settings best depth is at high GB control settings. If you have no clue what I’m trying to say, you are not ready for the Whites Pulsescan TDI. In high mineral conditions you are trading max depth for max iron rejection. You have to set the unit for the best balance for your conditions. But if you get it right, hold on. This detector is like no PI you've ever used. I have been able to run the Gain very high. I’m sure not everyone can based on where they are. So experiment, experiment, experiment! What about coils? Things might change depending on the coil you use. To summarize the TDI can find coins using two different methods. The simplest is to just run the detector tuned for best depth and dig low tones only. In high mineral ground this will produce coins VLF detectors have been unable to reach while passing on most common trash. The second method makes the TDI into a very effective coin detector, but the misadjustment of the ground balance ends up giving up the extra depth attained with the first method. Still, it does something no PI has ever been able to do before, and that is to find coins with nearly as much efficiency as a VLF detector. I do not want to give the impression I am pushing the TDI as a coin detector. If you want a detector strictly for coin detecting I suggest you get one to do just that. The real point of this article is to highlight that the TDI is a unique detector prone to experimentation. It is a machine for more serious detectorists willing to think outside the box. For those willing to dig some junk and having locations that favor the method, digging low tone targets will find deep coins missed by the best VLF detectors. The main use for the TDI is still nugget, beach, and relic detecting, make no mistake about that. But if you have a TDI , it can pay to experiment with it as there is really nothing else quite like it on the market. Thanks to Eric Foster and White's Electronics. White's TDI Information Page ~ Steve Herschbach Copyright © 2008 Herschbach Enterprises
  17. 1 point
    Jack Wade Creek runs along the Taylor Highway a few miles north of Chicken, Alaska. It has a long mining history. Jack Wade Creek is open to recreational gold panning from one-quarter mile (0.4 km) upstream of the Walker Fork Campground to the mining claims near Milepost 85. No permits are required. Panning is not allowed on adjacent mining claims. What's Allowed: gold pans, picks, pry bars, shovels, metal detectors, manually fed rocker boxes and sluice boxes. What's Not Allowed: Motorized equipment, including suction dredges, pumps, and earthmoving equipment; disturbing the Taylor Highway roadbed or shoulders. Jack Wade Creek is in the Fortymile Wild and Scenic River Corridor and so is subject to special rules and restrictions. Camping is prohibited between Walker Fork Campground (milepost 82) and Warner Creek (milepost 92). Camping for more than nine days at other locations may require a permit. See the BLM River Corridor Rules for details. Walker Fork Campground is a BLM fee campground with eighteen sites, outhouses, and a picnic area. Gold nuggets found by Steve Herschbach on Jack Wade Creek with a metal detector Note from Steve Herschbach: I spent a lot of time on Jack Wade Creek in 2013 and 2014 and found a lot of gold there metal detecting. I have stayed both in Chicken and commuted to Jack Wade to look for gold. I have also stayed at the very nice Walker Fork Campground. The campground saves a 40 mile round trip drive each day, but staying in Chicken can get you access to Wi-Fi for communications (no cell phones towers here). These trips were posted online at Steve's 2013 Alaska Gold Adventure and Steve's 2014 Alaska Gold Adventure. There are many photos and tips there that will be very helpful for anyone considering a trip to Chicken, Alaska and Jack Wade Creek. Jack Wade Creek Public Gold Panning Area Rules Jack Wade Creek Public Gold Panning Area Location Map
  18. 1 point
    The mention of Alaska has always conjured up visions of gold. Early gold-seekers traveled to Alaska by every means imaginable and endured endless hardships. They stayed to build communities in the wilderness. Present-day travelers, still lured by gold, come to Alaska to try their hand at panning or sluicing on the streams of the last frontier. They search for elusive gold nuggets or other semi-precious minerals. The Dalton Highway Built in 1974 to transport materials to oilfields on the North Slope, the Dalton Highway slices through northern Alaska, paralleling the Trans-Alaska Pipeline from Livengood to Prudhoe Bay. The BLM manages public land on both sides of the highway from the Yukon River to Mile 301. The state manages the land from there to Prudhoe Bay. The Dalton Highway is a gravel road that can be very rough, dusty or slippery, depending on weather. If stopping, pull as far to the right as you safely can. Do not block the gates on pipeline access roads. Off-highway vehicle use is prohibited within five miles of the highway. Carry emergency equipment, such as a CB radio, blankets or sleeping bags, spare tires, standard tools and first-aid equipment. Gas, restaurant food, lodging, phone, tire repair, and emergency towing are available at Yukon Crossing (summer only) Coldfoot, and Deadhorse. No other public services are available along the Dalton Highway. Recreational Mineral Collection Some BLM-managed public lands along the Dalton Highway south of Atigun Pass are open to recreational mineral collection. The BLM has inventoried and rated these streams for their mineral potential. The ratings are listed on the map below. Areas closed to recreational mineral collection include the pipeline right-of-way (27 feet on either side of the pipeline) and land legally claimed for mining or other purposes. You should stay at least 100 feet away from the pipeline to ensure you don't encroach on the right-of-way. To collect minerals on a private mining claim, you must obtain permission from the claimant. Check with the BLM's Public Information Center in Fairbanks (474-2251) to determine the claimant's name and address. The removal of placer gold on navigable waterways is regulated by the State of Alaska. For further information, contact the Department of Natural Resources at (907) 451-2705. Equipment You can use a pick, shovel, rocker and sluice box, and metal detector. Motorized equipment is not allowed. Suction dredging is prohibited within the Utility Corridor (the BLM-managed public lands surrounding the Dalton Highway) without prior authorization. Authorization can only be given for suction dredging on existing federal mining claims. Historic and Prehistoric Sites The 1906 Antiquities Act prohibits the removal, excavation or destruction of any historic or prehistoric ruin or monument, or any object of historic value located on federal land. Please notify the BLM if you find any items protected by the Antiquities Act. Maps For accurate locations obtain the following inch-to-the-mile maps from U.S. Geological Survey. 1:63,360 quads: Bettles C-2, D-1, D-2 Wiseman A-1, B-1 Chandalar B-6, C-6 Dalton Highway Gold Panning Sites - Click image for larger version The use of any motorized vehicle off the highway is prohibited within 5 miles on either side of the Dalton Highway without prior written authorization. This prohibition does not apply to off-road vehicles necessary for oil and gas exploration, development, production, or transportation or to a person who holds a mining claim in the vicinity of the highway, and who must use land within five miles of the right-of-way of the highway to gain access to their mining claim. Camping Marion Creek Campground, approximately five miles north of Coldfoot, is the only developed public campground along the Dalton Highway. It has both pull-through and tent sites, as well as outhouses and a water well. Each site has a picnic table and either a grill or a fire ring. This BLM federal fee site is open June through mid-September. Golden Age and Golden Access Passport holders pay half price. Campground hosts live on site. Travelers may also camp on gravel bars along rivers and in some pull-off areas left from old pipeline camps. Arctic soils and vegetation are easily damaged and take a long time to heal, so please practice “leave no trace” camping. Recreational camping is limited to 14 days at any one spot. Here is a list of parking areas, access points, and facilities. In general, be aware that facilities are few and far between on the Dalton Highway. Bring everything with you that you may need, including tools and spare tires. See the BLM Dalton Highway Visitor Guide 2017 for more information. Mile Agency Location Description 105.8 AF&G Kanuti River Small parking area and concrete boat launch to Kanuti River on east side of road. 115 BLM Arctic Circle Wayside Site is complete with a wayside, picnic tables, grills, restroom facilities, interpretive displays, and a campground. 132 BLM Gobblers Knob Wayside-Parking, toilet and scenic view. 135 DOT(P) Prospect Creek Day use campground area with restroom facilities and a boat launch area. Interpretation is planned. 136 BLM Jim River Parking and river access. 150 DOT(P) Grayling Lake A small turnout was identified as a potential site for interpretation of the archeology of the area. 156 BLM South Fork Koyukuk River Parking, unimproved boat launch at river crossing within highway ROW. 161 DOT(P) Chapman Lake Views of Brooks Range. Identified for improvements including a picnic area, restrooms, parking, and trails. 175-180 BLM Coldfoot/ Marion Creek Campground Amenities include a visitor center, restrooms, parking, campgrounds, and trailheads. Plans exist for interpretation. 186 DOT(P) Scenic Overlook Offers views of community of Wiseman and Koyukuk River. Interpretation about community and mining history possible. 188.5 DOT(P) Middle Fork Koyukuk Bridge #1 Bridge No.1 with turnout. Dolly Varden, grayling, whitefish. 197 DOT(P) Gold Creek Trailhead Established trails exist in area, parking and trailhead development at this site would improve access to the back country. 204-207 BLM Sukapak Mountain Overlook Small pull off could be expanded. The BLM has identified two potential sites for photo and interpretive opportunities. 207 DOT(P) Dietrich River Bridge Turnout to west at south end; burbot, grayling, whitefish and Dolly Varden. 211 DOT(P) Disaster Creek Served as a checkpoint during the development of the pipeline, interpretive opportunities exist, no scenic views. 235 DOT(P) Last Tree This site has been identified by the BLM as an interpretive site. Parking exists close by. For more information contact: U. S. Department of the Interior Bureau of Land Management Northern Field Office 1150 University Avenue Fairbanks, Alaska 99709-3844 (907) 474-2200 Related BLM publications: Birds along the Dalton Highway Dalton Highway Visitors Guide Bear Facts Current road conditions: Department of Transportation Recording: (907) 456-7623 Traveler's Advisory Radio: 1610 AM (originating at Fox, Alaska) Visitor information is available at: • Yukon Crossing Visitor Contact Station, Mile 56. Open Memorial Day to August 31 from 9 a.m. to 6 p.m., no phone. • Arctic Interagency Visitor Center, Mile 175. Open Memorial Day to Labor Day, 10 a.m. to 10 p.m., phone (907) 678-5209, fax (907) 678-2005. BLM Dalton Highway Visitor Guide 2017 BLM Dalton Highway Website Dalton Highway Corridor Management Area Source: The above is derived from the BLM brochure Dalton Highway - Areas Open to Recreational Mineral Collection.
  19. 1 point
    Sixmile Creek Gold Panning Area Early prospectors named Sixmile Creek because the creek was about six miles up Turnagain Arm from Cook Inlet. Gold was discovered in Sixmile Creek in 1895. In the 1930s, hydraulic mining was attempted. In recent years, there were several small suction dredge operations. Sixmile Creek has produced up to 2,000 troy ounces of gold, mainly in the area just below the confluence of Sixmile and Canyon creeks. A withdrawal bounded by the east bank of Sixmile Creek and a line 200 feet west of Hope Road’s centerline, is available for recreational panning—0.7 miles to 5 miles north of the Hope Junction (Map). Sixmile Creek south of Anchorage on the Kenai Peninsula Sixmile Creek flows through a broad glacial valley with numerous gravel bars and some bedrock exposures. Park at mile 2.4 on the Hope Road, at the pull-out on the east side and follow a steep trail down the road embankment to Sixmile Creek (Map). Gravel bars along this stretch of creek contain flat flour gold and occasional small flakes. Pans have produced 15–20 fine colors of flat, well worn gold. The south end of the gravel bar nearest the road is best, especially on the downstream side of larger rocks. Panning gravel on bedrock downstream from the bar can also produce gold. A rough trail from the north end of the parking lot will reach these sites that are best accessed during low water. Rusty-colored quartz float along the creek sometimes contains pyrite (fool’s gold). Suction dredges (4-inch or smaller) are only allowed from May 15 to July 15 with a free ADF&G permit and a ADEC permit ($25 annual fee). You can find good panning at mile 4.3 on the Hope Road (not shown on map). Pull out on a short side road into the trees and follow the trail to Sixmile Creek. You can find gold on point bars to the east and old channels next to the creek. Sixmile Creek Public Mining Site Here are a few simple rules and guidelines that all recreational gold panners must know: Recreational gold panning on the Chugach National Forest consists of the use of hand tools, panning, sluicing, and suction dredging with a 4-inch or smaller intake hose. You must follow all National Forest rules, such as camping limits, discharge of firearms, and use of trails. You can find regulations in Title 36 Code of Federal Regulations (CFR), with general prohibitions in part 261. Review these regulations before you go gold panning. You can find copies of these regulations on the Internet and at Chugach National Forest offices in Anchorage, Girdwood, Seward, and Moose Pass. You can use gold pans and hand tools-fed sluice boxes year round in the streams listed in this booklet. No hydraulic mining or use of earth-moving equipment is allowed. Work only the active stream channel or unvegetated gravel bars. Do not dig in stream banks! You are not allowed to build structures, cut trees or dig up archaeological, historical, or paleontological objects, nor are you allowed to obstruct others in their recreational pursuits. If you find those objects, please report them to the Chugach National Forest. Suction dredges (4-inch nozzles or smaller) are permitted from May 15 to July 15 only. Remember that permits are required. The Kenai Peninsula is home to brown and black bears. Stay alert and avoid bears whenever possible. For more information, get Bear Facts from the U.S. Forest Service or Alaska Public Lands Information Centers. The water is cold and you can expect to get wet— after all, the gold is in the water. Wear insulated waterproof boots and gloves. Wool clothing can keep you warm even when wet. Bring extra clothing and dress in layers. Keep Alaska green, do not trash or litter. Many places have a $1,000 fine for littering. Follow Leave No Trace principles. Good luck and good prospecting! Sixmile Creek, Alaska in 2014 Most of the information above was derived from GOLD PANNING, Guide to Recreational Gold Panning on the Kenai Peninsula, Chugach National Forest, Alaska (2018) found here - See the full text for more information and details.
  20. 1 point
    A suction gold dredge is basically an underwater vacuum cleaner. Material is transported from underwater to the surface and run through a sluice box to capture the gold. A sluice box works because gold is 15 times heavier than sand and gravel and so is easily trapped by the riffles and carpet in the sluice box. Dredges almost always need to be mounted on a set of floats. This is because a dredge has just enough power to lift water and gravel to just above the surface of the water. Every inch of vertical lift above the surface of the water robs power/suction from the system. Floats are also needed because there is rarely a nice gravel bar in just the right place to set up a dredge without floats. Manufacturers rate suction dredges by the inside diameter of the main suction hose. So a 5" dredge has a main suction hose with a 5" inside diameter. However, nozzles are used on dredges which restrict the intake to a size smaller than the inside diameter to help prevent clogs. A 5" dredge may have a nozzle opening of 4" for this reason. The volume of material processed is determined by the nozzle opening, not the inside diameter of the hose. Therefore most dredge permits refer to the nozzle size, not the hose size, when imposing rules and restrictions. This is a very important thing to remember when working with permits. What a dredge manufacturer calls a 5" dredge may be a 4" intake nozzle dredge for permitting purposes. Nozzles sizes may be up to 2" smaller than hose sizes. A gold dredge is powered by a motor and pump. A common misperception is that gravel is sucked through the pump. The pump actually pumps only water, which is delivered to a venturi type device (called a power jet or a suction nozzle) which indirectly creates suction in a larger hose. The solves two problems. First, gravel pumps are very expensive, heavy, and high maintenance items. Second, a 2" pump can easily be used with a venturi to create suction in a 4" hose, greatly increasing the volume of material that can be processed. A common suction gold dredge design - 4" surface dredge with air compressor In normal operation a gold dredge is run by an operator at the intake nozzle who directs the nozzle and who captures and discards oversized rocks that would plug the intake hose. A properly set up sluice box does not need tending - all the material sucked up passes over the riffles with no extra attention needed by the operator. The operator can therefore stay at the nozzle and process material until the motor runs out of gas and needs refilling. The sluice box normally need not be cleaned out more than once a day at the end of the day. The riffles and carpet are removed and all material (concentrates) in the box washed into a tub and panned out with a simple gold pan. Larger dredges may employ gold wheels or other devices to aid in the cleanup of the concentrates. The diagram below shows a basic suction dredge flowchart. The foot valve is a one way valve with a screen. Nearly all dredge pumps are not self priming because the mechanism that enable self priming results in a less efficient pump. Simple fire fighting type high pressure, high volume pumps are employed which need to be primed before starting the motor. This explanation from Keene Engineering: "Before starting the engine, the pump must be fully primed. This means the pump must be full of water and all air removed. All jetting pumps provided with our dredges have a mechanical water pump seal. Without the presence of water in the pump, friction could cause a seal to overheat and require replacement. Priming the pump on some of the smaller models is accomplished by thrusting the foot valve back and forth under the surface of the water in a reciprocating motion. This will cause water to become pumped into the foot valve assembly into the pump. A pump is fully primed when water is observed flowing out of the discharge end of the pump. It sometimes may become necessary to hold the discharge hose above the level of the pump to complete the priming operation. The larger dredges that have a rigid foot valve, are easily primed by removing the cap provided on the foot valve and filling, until water overflows. Caution must be exercised to prevent sand from entering the foot valve or intake portion of the pump. Excess amounts of sand could dam age the water pump seal, or pump impeller. It is recommended that the intake portion of the foot valve be placed in a sand free environment underwater." The intake screen prevents large items from entering the pump, but sand can still pass through and cause excessive wear over time. Place the foot valve on rocks, in a bucket underwater, or strap it under the floats to keep it off the bottom and out of sand. Once a system is properly primed the one way valve retains the prime even if the pump is shut off, allowing for easy restarts. If the foot valve is allowed to suck air and the prime is lost, shut off the pump as quickly as possible to prevent damage to the pump seal. It is a good idea to always have a spare pump seal as once one is damaged the dredging operation will be at a standstill until a new one is installed. Water entering the footvalve passes through the pump intake hose and into the pump. It is pumped into the pressure hose and then into the venturi device that creates the suction in the main suction hose. The most common device is the power jet, which is installed in between the sluice box and the main suction hose. A power jet pulls material up and into the sluice box. An alternative is the suction nozzle which installs on the end of the suction hose in place of the suction tip. A suction nozzle pushes material up the suction hose and into the sluice box. Power jets take less hose and are more efficient so therefore very common. However, care must be taken to not suck air into the main suction hose or the system will stop working until all the air is purged from the hose. A suction nozzle keeps water in the system at all times and so is preferred for shallow water use where sucking air into the nozzle is inevitable. Suction nozzles are rarely seen as a stock item except on 1.5" or 2" dredges and must be added as an accessory item on larger dredges. The main suction hose is attached to the intake end of the power jet. It varies from 10 feet long on small dredges to 20 feet or more on larger dredges. A suction tip is fastened into the intake end of the hose which has a reduced opening to help prevent hose clogs. The discharge end of the power jet plugs into a flare. The flare widens the flow of material out to the width of the sluice box, and in doing so slows the speed at which the material enters the sluice box. When the material enters the sluice box it passes over a classifier screen and under a damper. The damper is usually a large sheet of rubber best seen in the photo at the top of this page, that rides on top of the flow of water. It smoothes the water flow and forces any small gold that may be riding on top of the water back into the main flow. The classifier screen also acts to slow the flow of water and create a partial separation of the large rocks from the smaller gold bearing material, which passes through the screen and directly into the first couple riffles. The screen may be a punch plate or a heavy wire mesh with holes varying from 1/4" to 1" in size. The main gold capturing section of the sluice box has riffles over a carpet. The riffles create gold traps which direct the gold into the carpet which captures and holds the gold. Many types of riffle designs exist, the most common being an inverted "L" design referred to as "hungarian riffles". Expanded metal screening of various types are also used in many sluice boxes as a riffle or in conjunction with other riffle types. Carpets employed included black ribbed rubber matting, riffled indoor/outdoor carpeting, and a type of carpeting referred to as "miners moss". Miners moss is a nickname for a type of commonly used in building entryways that looks like pressed spaghetti. The original design is 3M Nomad® but third party alternatives have recently become available. The open weave design that makes it good for trapping dirt from the bottom of shoes also makes it an excellent gold trapping carpet. Hookah Diving Air System An optional component on most suction dredges is an air compressor which is operated off the same motor as the pump via a belt and pulley arrangement. The air compressor is a special breathing air compressor than can deliver air to a diver underwater for as long as the motor is running. The air is delivered to the diver with an airline, reserve tank, and regulator. Surface air supply dive systems are commonly referred to as hookah diving systems. Dredges are normally sold as complete units but most component parts can be obtained separately as replacement parts or to build a custom dredge out of parts. ~ Steve Herschbach Copyright © 2012 Herschbach Enterprises
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