wirelessguy

tvanho, if you are comfortable with your iPhone or Android phone I agree with Norvic that you already have a gps and camera and compass. Get a purpose built rugged case if it's something you'll take in the bush. I use google maps on both android and iphone and it's adequate for basics and is simpler than a dedicated gps for sure. Very few menus to figure out and if you use google maps on a computer easier yet. I use my phone gps for off and on road vehicular travel, cause I always have my phone then. When I'm in the bush I use a dedicated gps 'cause I'm a gadget guy, my dedicated gps has better location performance (be sure to get a dual mode glasnoss/gps), I like and use a lot of the features, it's inherently much much more rigged. As far as a camera helping you with general gps usage, I dunno. Never thought of it 'til I read your post.

My sentiments exactly

Super informative and clarifying video and thread! Helps me a ton. Thanks Steve, JP and other contributors. My own experience and tests in my environment (all in a hard quartz - mild ground - environment) also do not show benefits or uses for general and extra deep. High Yield gives me a more definiitive response all my tests to date over general and extra deep. And now I know why insofar as extra deep is concerned - I haven't tested in heavily mineralized ground. Still learning! Maybe I will find a useful strategy using these two gold modes for discerning different types of problematic hot rock I do encounter ??? A question: In this video for the detectorist, when Phil uses the phrase "push the detector hard" does he mean "increase the transmit coil current (power)" if he were speaking in electrical engineering terms?

Lunk Thanks for this good thread documenting your early results with the Zed. Informative and inspirational! The quote above, along with this super informative thread http://www.detectorprospector.com/forum/topic/826-minelab-video-gpz-7000-gold-mode/ give more evidence that High Yield is the go to Gold Mode in most instances. I have found that to be true in my first few weeks experience with the Zed hunting in hard quartz which regionally or occasionally contains various hot rock. I have yet to find a proven benefit for the general or extra deep gold modes in my application; and to be clear, I am still learning.

Look up 'inverse square law' on Wikipedia and you will se what I am talking about. You're right about energy traveling out from the source in 3 dimensions, it travels out in an ever expanding sphere. My explanation and mathematics are correct the inverse square law takes into consideration all 3 dimensions. Gold Hound, The total energy across a unit area of an electromagentic field in the far field decreases proportional to 1/r^2 with r being the distance from the radiator. Far field by all definitions and approximations = more than a wavelength. If we approximate the frequency involved with metal detection as 20 kHz we get 15,000 meters wavelength using c=(freq)(wavelegth) with c= speed of light = 3*10^8 m/s. So that is a range left for charlatans and heretics with their divining rods and long range locators. So 1/r^2 is valid for distances far far greater than we are talking about finding gold nuggets. And this paragraph above has nothing to do with metal detection using induction balance, pulse induction or zero voltage transmission. That is because all metal detectors are based on induction principles - magnetic field only. NOT electromagnetic plane waves (radio waves) propagation. The metal detector coil is not an "antenna". In my 30+ yrs of radio frequency engineering practice I find the concept of near field and far field as a function of wavelength used widely in electromagnetic plane wave (radio wave) practice and are not so much used in inductive (magnetic) field practice such as in the design and winding of inductors, transformers. Specific geometries come far more into play governing the magnetic field strength at points in the area of interest. I am still a relative newbie to metal detecting however have devoured literature (including tons of lore on blogs) on the details of the transmitted magnetic field from an MD coil and the return eddy current from the target to the receive coil. I guess I differ with your statement above. I find it extremely complicated. I find the best simplification that exists on field strength that has merit in the physics of magnetic fields is the 1/r^3 approximation Reno Chris and jasong note. ( I don't find Chris' reasoning above for the 1/r^3 approximation accurate). I have read a few different credible reasonings for the field strength approximation of 1/r^3 under many applicable scenarios of dipole approximation of a current loop and size of area this applies to (size of target) relative to the loop. 1/r^3 approximation is widely quoted by strong technical people in the metal detector field. As Chris notes, returned field strength loss vs distance becomes 1/r^6 if you consider transmit magnetic field to energize the target and the the return path of eddy current from target to the receive coil. HOWEVER, 1/r^3 is an approximation with multiple ifs and thens and the actual math is complicated particularly close to the coil. I think the metal detector manufacturers must simplify all this physics with best visual models of cones and blades when it comes to using the metal detector. Humans don't generally visualize in terms of graphs and equations. So, the way that I, an inexperienced user, experienced RF engineer, reconcile statements that Steve H and others make about those cone and blade approximations is that these experienced users are integrating a lot of experience on different size targets at different distances, with different coils, in different conditions and using a lot attention to detail in their practice and have observed the physics exceptions to the visual approximation. Good info, more nuanced than a brand_new_first_times_in_the_field metal detector user needs. http://www.geotech1.com is a great site for the engineering and physics side of metal detecting if you have not already found it.

I bought one of those half batteries (actually a refurbished battery) from the ebay guy at the link above. You can send him your existing battery and he'll refurbish. He also had some in inventory for sale when I bought a month ago. Advertised at about 6 hrs run time.

I recently bought a refurbished Minelab lead acid battery for GP series from this 100% positive feedback member on Ebay. http://www.ebay.com/usr/miner_mark?_trksid=p2047675.l2559 Battery works great, price was right and delivery very prompt.

"loose lips sink ships" ... indeed!

BINGO! I was thinking the exact same thing last night when I read this thread and the chart comparing GPZ and GPX 5000 having "same " performance and planned to pose in form of a Q this AM. Steve insightfully answered my Q before I could write it! As has been the case all over this excellent web site. I am told by my USA dealer he should be able to ship my paid for GPZ 7000 early next week. Can't wait!

"640k is more memory than anyone will ever need" "everything that can be invented, has been invented" I dunno Steve. I don't think it's a good bet to bet against technological advances. Electronic prospecting suffers from being such a small market worldwide. There really are a very small number of talented engineers and scientists working on the problem. In a recent forum conversation with Carl Moreland on the topic he replied to me there are probably more engineers developing 35 mm film cameras than metal detectors today. As you have noted Minelab seems to have no company biting its heels in second place. I don't have a logical prediction of what will trump GPZ 7000 (assuming it proves to be another quantum success). I'll throw a couple thoughts out though. In most of my lifetime (and I'm the same age as you) technology advancements have mostly been made in corporations and by people working full time in the craft. The only notable area where amateur hobbyists were consistent dabblers and improvers was ham radio. In the last decade or so we've seen a huge rise in what's often termed the "maker movement". It is a large groundswell of DIYers. Not just technology for sure, even bloggers might loosely be in the movement. In the last 10 years, a <$100 kit of microcontroller board with various I/O (input/output) and a simple programming language you can learn on your own and an internet of people teaching and sharing has become widespread. Readily available $10ish chips have more computing power than Apollo 11. Doing this stuff is very quickly getting to more people who are interested and have chutzpah. Maybe it's not low frequency induction based technology after the GPZ? Imaging is advancing so rapidly. In the 90s 1 MPixel was high def and expensive. Add image recognition which is growing in capability radically to cheap digital imagery and maybe someone can move ground penetrating radar (way more depth than induction techniques) into enough resolution to economically determine a nugget from a nail? (I know, I know I know, ... a lot more issues than just that. some engineers read this stuff :-) ) I am not predicting "what" specifically as much as I bet on "will" happen. For sure some ebbs and floods just like the last two centuries of gold rushes.

Thanks for the link Steve.

Jasong, can you provide the patent number you are referring to please? Any other GPZ 7000 relevant patents numbers appreciated as well. thx

My professional wireless background is far more involved in audio headsets than metal detectors so I'll strive to be brief and specific on the topics in this thread. (brief is difficult for me) Bluetooth (a technology brand) is indeed a more widely popular standard than Kleer (a company name which uses a proprietary technology). Kleer based products almost always come in a pair a dongle (plugs into audio jack or maybe USB) and a headset. Kleer main claims to fame are low latency and lossless audio (in laymen's terms this means very clear audio). So, to support vanerspaul's assertion, you are not likely to go wrong with Kleer based audio jack dongle and headset. Bluetooth headsets tend to be sold standalone to work with a phone, computer, tablet, which has an embedded bluetooth capability. If you find a Bluetooth audio jack dongle and headset combination, look for "low latency A2DP". Otherwise you may end up with a latency problem as Steve notes above. (OK, one nerdy thing - for lip synch audio, matching video human speaking to audio, the rule of thumb is less than ~ 40mSec latency. So in our application, matching MD swing (eyeball) to sound, look for less than 40 mSec latency on the specs of your headset audio dongle combo.) To summarize for those not wanting to be wireless audio pros, you are less likely to make a mistake with Kleer based audio dongle and headset products. The GPZ 7000 is based on a 2.4 GHz proprietary technology of Texas Instruments (per FCC submissions). Bluetooth and Kleer also use the 2.4 GHz band. 2.4 GHz is not in and of itself magic. There is crap and great audio stuff using the 2.4 GHz frequency band. Minelab's choice of the TI technology means they are going to keep their wireless audio link a closed system so you can't go buy a wireless headset to mate with your GPZ 7000 directly. You'll buy a corded audio headset to plug into the GPZ 7000 WM 12 just like on the CTX 3030 WM10 module.

Junkman, I'll speculate the Aussie marketeers ran into some Apple folk at a bar or conference and got a few pointers on "Hype 101". We'll all forget about this phase of product introduction if the GPZ 7000 proves to be worthy like the first iPod, iPhone, iPad which indeed fully delivered.

$9999.00 USD

Steve, in your GPZ 7000 specs page you note the standard search coil is a 14 inch double D. Why do you believe double D? Advert only says 14 inch. Do you know if a mono will be available at launch, too?

Quadcopter drones are non-trivial to pilot. Master flying one of the Hubsan X4 Quadcopters ($43 at Amazon) before you crash and burn a quad that can carry a camera. Get the blade protector for $3.

Thanks for the guess Steve. I worked 7 yrs in a consumer/B2B market estimated at $2B worldwide. There was one noteworthy market research firm covering that market which was dominated by 2 companies worldwide for the last 25 years. That $2B market was not big enough to get Apple/Panasonic/Samsung/ ... interest nor get serious, well funded new player. So, it stays a duopoly today and also lacks innovation. Innovation is hard to do profitably. The general public only sees the successes (Steve's XP example above) not the failures and wasted $. Failures inside big well known companies and the myriads of failed start-ups. This makes financially tightly managed companies tentative on innovative new product development and market introduction. Having said that, as a newbie detectorist, and > 30 year wireless engineer, executive, entrepreneur, (now well armed after reading Inside the Metal Detector !!!) I agree with Steve there is low hanging fruit for innovation in the MD industry. In addition to Steve's list I gotta believe there is much to be gained in digital signal processing in MDs for better discrimination - the much desired "discrimination in a PI at depth" does not seem to me to be as much a pure physics problem as an application of minds and $ problem.

Thanks for the input, Mike. Do you have any pointers on where to find figure 8 coil building tips other than the geotech site?

What is the total $ size of the word-wide hobby metal detector market? I dunno. I'll guess that it is so small that no market research firm even studies it, hence we may not get any objective answer to my Q. The biggest reason that there are few market releases of breakthru products, is that the market is so small there is relatively little money put into it. If there was a big growing market, consumer product companies with big $ would put more serious R&D into it.

Congrats Steve! Beautiful specimen for sure.

I have an application for a specialized metal detector coil. I want to use a Whites MXT to provide ferrous/non-ferrous discrimination information on targets which are deeper in quartz than common metal detector depths (2-30 feet). These targets were not found with found a metal detector. I want to insert a metal detector probe encased in PVC pipe into a 2” dia hole bored into the quartz. Reading Carl Moreland's “Coil Basics” tutorial at http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=info.dat it seems to me one of the figure 8 configurations would work well in this application. I would insert the probe on adequate length sections of PVC into the drilled hole and connect to the MXT. I’m armed with no metal detector probe building experience, a lot of RF experience, adequate test equipment. Will this idea work in general? Is one of the figure 8 configs the right topology? Any other hints on making this probe before I start? What distance from centerline of 2” dia drilled hole can I expect to discriminate on a US nickel sized object for ferrous/non-ferrous?

"Where would you have so much quartz that it would cover the ground?" under the ground

Steve, thanks for the advice. Makes sense. More to advance my knowledge than to influence my backyard, can you comment on Q1 and Q2?

I am new to detecting and gold prospecting and have opportunity to prospect in a quartz environment which has historically produced gold. I am not yet up to the traditional 100 hours time on my metal detector and the prospecting site is a journey away. I have been practicing in my back yard getting familiar with a Whites MXT Pro. I also have access to a Gold Bug Pro although I have not yet spent much time on it. I have some test garden Qs. 1) Would I be able to simulate the quartz environment I'm prospecting in with a test garden of silica sand? The ground reading on my MXT pro varies from -50s to -80s at the prospecting site. 2) As an alternative to siiica sand, what about construction Quartz flagstone? Would I be able to simulate the quartz environment better than silica sand with this? My intuition is no, the air voids between pieces would just make unnaturally discontinuous permeability. 3) Is the hassle/benefit of building a silica sand (or quartz flagstone) test garden worthwhile relative to just using my native backyard soil? I'd like to have a better feel for what size gold target I could find at what depth in the quartz environment. Not at all sure how well what I do in my backyard correlates to the real environment in this regard. Let's say the answer to 1 (or 2) is "yes". Is the build worth the hassle? ($ not too big an issue for me, yet no one wants to waste time or $) Should I just get used to what the controls do in the backyard and go prospect and learn more about the environment IN the environment?