Tin, Bolts, Washers, And Other Ferrous Items That Read As Non-Ferrous
By Steve Herschbach
Which metal detectors have the most reliable target ID numbers?
Target ID is a function of depth - the deeper the target, the more difficult it is to get a clean target ID as the ground signal interferes. Other items directly adjacent to the desired target can also cause inaccurate numbers. The more conductive the item, the higher the resulting ID number, but also the larger the item the higher the number. Silver is more conductive than gold, so a gold item will give a lower number than the same size silver item. But a very large gold item can give a higher number than a small silver item, so numbers do not identify types of metal. Gold and aluminum read the same and vary in size so to dig one you dig the other. Only mass produced items like coins produce numbers that are more or less the same over the years but a zinc penny will read lower than a copper penny due to the change in composition.
In general iron or ferrous targets produce negative numbers or low numbers. Aluminum, gold, and US nickels produce mid-range numbers. And most other US coins produce high numbers. Other countries coins, like Canadian coins with ferrous content, can read all over the place.
The scale applied varies according to manufacturer so the number produced by each detector will vary according to the scale used. The 0-100 range for non-ferrous targets is most common but there are others. Minelab employs a dual number system on a 2D scale with thousands of possible numbers, but they are now normalizing the results produced to conform more closely to the linear scale used by other manufacturers.
Increasing ground mineralization has a huge effect on the ability to get a good target ID. Ground mineralization is nearly always from iron mineralization, and this tends to make weak targets, whether very small targets or very deep targets, misidentify. The target numbers get dragged lower, and many non-ferrous targets will eventually be identified as iron if buried deep enough. Small non-ferrous readings and iron readings actually overlap. That is why any discrimination at all is particularly risky for gold nugget hunters.
If you want target ID numbers to settle down, lower sensitivity and practice consistent coil control. The target number will often vary depending on how well the target is centered and how fast the coil moves.
Higher sensitivity settings lead to jumpier numbers as the detectors become less stable at higher levels. The interference from the ground signal increases and interference from outside electrical sources also increases, leading to less stable numbers.
Higher frequency detectors are inherently more sensitive and are jumpier. So lean lower frequency for more solid results. Multi frequency detectors act like low frequency detectors and tend to have more solid target numbers due to the ability to analyze a target with different frequencies.
Another issue is the number of target categories, or ID segments, or VDIs, or notches, or bins (all names for the same thing) that a detector offers.
For instance here are the number of possible target id categories or segments each detector below offers:
Fisher CZ-3D = 7
Garrett Ace 250 = 12
Minelab X-Terra 305 = 12
Minelab X-Terra 505 = 19
Minelab X-Terra 705 = 28
Minelab Equinox = 50
Fisher F75 (and many other models) = 99
White's MXT (and many other models) = 190
Minelab CTX 3030 = 1750
Fewer target categories means more possible items get lumped together under a single reading, but that the reading is more stable. Many detectors will tell you the difference between a dime and a quarter. The Fisher CZ assumes you want to dig both so puts them under one segment along with most other coins.
People who use detectors with many target numbers usually just watch the numbers jump around and mentally average the results. Some high end detectors can actually do this averaging for you! But I think there is something to be said for owning a detector that simplifies things and offers less possible numbers to start with. The old Fisher CZ method still appeals to me, especially for coin detecting. So do detectors like the Garrett Ace 250 or Minelab X-Terra 505 for the same reason.
The problem is that as people strive to dig deeper targets or smaller targets the numbers will always get less reliable. But if you want to have a quiet performing metal detecting with solid, reliable target numbers look more for coin type detectors running at lower frequencies under 10 kHz or at multiple frequencies and possibly consider getting a detector with fewer possible target segments. And with any detector no matter what just back that sensitivity setting off and you will get more reliable target numbers.
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Detectors often use tones to identify targets and often use far fewer tones than indicated by the possible visual target id numbers. The X-Terra 705 for instance can use 28 tones, one for each segment. However, most people find this too busy, and so simple tone schemes of two, three, or four tones may be selected. I think it is instructive that many people often end up ignoring screen readings and hunting by ear, using just a few tones. This ends up just being an ultra simple target id system much like the simpler units offer. Reality is that most people do not need or care about huge numbers of target numbers. For many just three ranges suffice, low tone for iron, mid tone for most gold items, and high tone for most US coins. The meter could do the same thing, but for marketing purposes more is better and so we get sold on detectors with hundreds of possible target ID numbers. Perhaps that represents a digital representation of an old analog meter with its nearly infinite range of response but the reality is we do not need that level of differentiation to make a simple dig or no dig decision.
Finally, a picture often says it all. Below we have a shot of the White's M6 meter. I like it because the decal below illustrates a lot. You see the possible numerical range of -95 to 95 laid out in the middle. Over it is the simplified iron/gold/silver range. Note the slants where they overlap to indicate the readings really do overlap. Then you get the probable target icons. -95 is noted as "hot rock" because many do read there.
The M6 can generate 7 tones depending on the target category. I have added red lines to the image to show where these tones sit in relation to the scale. It breaks down as follows:
-95 = 57 Hz (Very Low) Hot Rock
-94 to -6 = 128 Hz (Low) Iron Junk
-5 to 7 = 145 Hz (Med Low) Gold Earrings, Chains - Foil
8 to 26 = 182 Hz (Medium) Women's Gold Rings/Nickel - Small Pull Tabs
27 to 49 = 259 Hz (Med Hi) Men's Gold Rings - Large Pull Tabs
50 to 70 = 411 Hz (High) Zinc Penny/Indian Head Penny - Screw Caps
71 to 95 = 900 Hz (Very High) Copper Penny/Dime/Quarter/Dollar
Note that the screen reading of +14 is noted as being a nickel or ring but it can also be the "beaver tail" part of an aluminum pull tab or the aluminum ring that holds an eraser on a pencil, among other things.
The best book ever written on the subject of discrimination is "Taking A Closer Look At Metal Detector Discrimination" by Robert C. Brockett. It is out of print but if you find a copy grab it, assuming the topic interests you.
Always remember - when in doubt, dig it out! Your eyes are the best target ID method available.
By Steve Herschbach
Our cup runneth over!
Just a few years ago the market for "over 30 kHz nugget detectors" was quite limited. For a long time there were only a few options:
Fisher Gold Bug 2 (71 kHz) $764 with one coil
Minelab Eureka Gold (6.4, 20, & 60 kHz) Discontinued $1049 when new with one coil
White's GMZ (50 kHz) Discontinued $499 when new with one coil
White's GMT (48 khz) $729 with one coil
Things were that way for over a decade. Then in 2015 Makro introduced the Gold Racer (56 kHz) $599 with one coil. Sister company Nokta released the AU Gold Finder (56 kHz) $799 with two coils
Then in 2017 we see the Minelab Gold Monster 1000 (45 khz) at $799 with two coils. And although not a dedicated nugget detector, the Deus high frequency coil options (up to 80 kHz) were also released, $1520 for complete detector with one HF coil.
Now in 2018 we get another general purpose machine, the Equinox 800, that can hit 40 khz, $899 with one coil. And just announced...
the Makro Gold Kruzer (61 kHz) $749 with two coils and
the White's Goldmaster 24K (48 khz) $749 with two coils
These last two announcements have made barely a ripple in the prospecting world, or at least going by other forums that seems to be the case. There are various reason for that (forums not being prospecting oriented or being Minelab centric) but still the lack of buzz is interesting. I do believe people are both burned out by all the new introductions and that the market is saturated with high frequency models. Leaving out the general purpose machines to sum up the current options it looks like the current "sweet spot" for pricing is a high frequency model at $749 with two coils.
Makro Gold Racer 56 kHz - $599 one coil
White's Goldmaster 24K 48 kHz - $649 one coil
White's GMT 48 khz - $729 one coil
White's Goldmaster 24K 48 kHz - $749 two coils
Makro Gold Kruzer 61 kHz - $749 two coils
Fisher Gold Bug 2 71 kHz - $764 one coil
Minelab Gold Monster 1000 45 kHz - $799 two coils
Nokta AU Gold Finder 56 kHz - $799 two coils
High Frequency Gold Nugget Detector Roundup
Hi, I am looking to purchase a gold finding metal detector that can handle mineralized soil well, but also locates smaller gold. I live in southern Nevada and it seems that the more I read, the more confused I am getting. I guess I'm looking for a detector that does well with tiny and larger gold. I had the Gold Bug 2 for a while and it was way too sensitive for me and not rain-proof. The Makro Gold Kruzer, The Gold Monster and others on that level are all within my price range, so I am having trouble making a decision. I understand that the right detector for someone may not be the right detector for someone else, but I do believe the right input is valuable. I haven't seen any head to head videos using the Gold Kruzer yet (still too new) but it looks promising so far. The reviews of these detectors are great, but nothing beats real world testing under various conditions and soil types. I am not one for air testing due to it's controlled nature, so the confusion grows. I know many of these detectors can locate tiny gold due to their higher kHz, but there is a trade off. I appreciate any suggestions. Thank you, Mike
By Steve Herschbach
I have used many metal detectors over the years, and right now I have to say that the new Makro Racer 2 has perhaps the easiest to understand, best laid out, most practical display and menu system I have ever seen in a top end detector. Now, you can sure say you hunt by ear and do not need a screen and I get that, but if we are going to put a screen on a detector, then let's do it right.
Simple detectors with few functions are easy to make screens for - there is not much you need. But even then just the basics are often wrong. Machines that feature target id numbers, what is the thing you will most look at on screen? The target id numbers! Yet these are often way too small or off to the side as if an afterthought.
The Makro Racer 2 id numbers are huge, much larger than on the original Racer and Gold Racer, which are already good sized. The number 88 display in the diagram above is fully 1.5" x 1.5" in size in real life. Other machines have some pretty big numbers but I think this sets a record as I can't think of any machine with larger id numbers on screen though some are close.
Makro Racer 2 LCD display and controls
Makro Racer 2 screen layout
Makro Racer 2 screen and control descriptions
The number can be the ground balance number, target id, or depth reading. You get a text display just above the number confirming which it is. Below the numbers are three zone references, Fe, Gold/Non-FE, and Non-Fe, that are used to set tone breaks and audio for the three main zones or bins as they are sometimes called.
Another basic feature lacking on a lot of machines - the meter backlight. With the Racer 2 you get off, intermittent, or full time backlighting, and it includes the translucent red control buttons. The control ranges between 0-5 and C1-C5. At 0 level, the keypad and display backlight are off. When set between 1-5, they light up only for a short period of time when a target is detected or while navigating the menu and then it goes off. At C1-C5 levels, the keypad and display will light up constantly. I do not know of anyone doing a better backlight.
The right side of the meter is informational - ground phase (ground balance number), mineral % (ground magnetite content), coil warning notices, and a six segment battery meter.
Across the top below the 0 - 99 reference sticker, is a series of 50 "bullets" each of which covers 2 target id numbers. Open bullets (which appear gray in the diagram but are invisible in real life - see top photo) indicate accepted target id numbers. Blacked out segments show what discrimination and notch setting you have programmed in a single quick glance. When a target is detected, the big number on the display will be mirrored by one or more of the bullets flashing dark.
The four control buttons are simple as can be - up and down takes you through the left hand menu area. Right or left lets you set each function selected by going up and down. The menu is basically the entire feature list just laid out right there for you to see. You want to know what this machine can do, just look at the screen. Most other machines you have no clue without reading the owners manual or at least pushing buttons to see what functions appear.
Some settings like the backlight are system wide for all modes. All other settings like Gain are independent in each mode, and can be saved independently in each mode. This means you can play neat tricks like setting up a couple modes with dramatically different settings and then flip back and forth easily between two modes for target checking.
You even get to decide what mode is the default start up mode. The Racer 2 starts up in the last mode where the save function was performed. If you always want to start in Beach mode, just modify and save something in Beach mode. Next time you start the detector, you will be in Beach mode.
It is simple. It makes sense. No cryptic abbreviations or acronyms. No sub menus. It is, in metal detector terms, a work of art. Whoever designed this should sign it so I can frame it and hang it on my wall.
By Steve Herschbach
First Texas (Bounty Hunter, Fisher, Teknetics) - last new models Fisher F75+ and Teknetics T2+. Next up a new pulse induction (PI) beach detector. A new digital multifrequency to replace the Fisher CZ3D is long overdue but at this rate we will be lucky to just see the PI before the end of the year.
Garrett - last new model the AT Max. Hard to believe the flagship GTI 2500 has been around since 1999 with no updates. Garrett so far has shown no interest in multifrequency. The most I was hoping for was a lightweight dry land version of the ATX, but so far no sign of that happening either. I doubt we will see anything else from Garrett this year but they could surprise.
Makro - last new models the Multi Kruzer and Gold Kruzer. Makro has mastered single frequency so everyone would like to see what they can do with multifrequency or pulse induction. I expect Makro is done with new models for the year.
Minelab - last new models Equinox 600 and 800. I have no idea what’s up next for detectors but I sure would like to see that small coil for my GPZ 7000. I really don’t expect anything new for the rest of the year besides Equinox accessories.
Nokta - sister company to Makro. Last new detector the Nokta Impact. I actually bet on a PI under the Nokta brand rather than Makro brand simply because the Nokta housings like the new Impact housing would better contain a high power PI.
Tesoro - Who? What?
White’s - last new models the MX7 and TDI SL Special Edition plus the just announced Goldmaster 24K. Hopefully that new tech will eventually see the light. Right now just getting the 24K out the door is job one.
XP - last new products the HF coils for the Deus, with X35 coils due by end of year.