By Steve Herschbach
The World's First Smart Detector & Imaging System that can display the shape, depth and dimensions of underground metals in real time. Ideal for Deep Treasure Hunters, Archaeologists, Municipalities, Utility Companies, CSI and Law Enforcement Agencies.
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.
Disclaimer: I've only really been interested in Gold hunting so I'm pretty clueless in using my Nox for jewellery hunting.
This might be a challenging one, a farmer I knows wife lost her wedding ring in a paddock and didn't realise, Later the same day they run a plough or some sort of farming gadget over the paddock as they planted it out with grass seed so the ring is likely buried. They're pretty certain it was lost in this paddock.
I have been recruited to try find this ring, it's 24k gold with about 20 diamonds on it. The guy originally gave me the wrong description of the ring, probably his ex-wife's ring he described as he said it had 1 diamond and sapphires 😄
The paddock is really junk filled, I went and swung my detector over it yesterday morning before skiing and there was iron I assume setting the detector off everywhere in all metal mode.
I know the VDI numbers are extremely useful for coin hunting but will they help for finding this ring, I really don't want to have to dig everything! Is there a range I should be targeting? I assume Field 1 will be the best mode or maybe Park 1 seeing there is a lot of junk?
Small gold when prospecting always comes up under 10 on the VDI's, I am guessing a ring will come up higher?
Would the Equinox be my best choice or would I be better off using my T2 with Mars Tiger 10x13" or 15" round Stock T2 coil for more ground coverage? I also have a Garrett Euroace with Nel Tornado 12x13" I could use if that would be best. That's the biggest coils I own.
I have a GPX 4500 with a 15x12 DD Commander I could use but I don't want to dig lots of junk and I was hoping VDI's would be useful.
I told them I'd do the hunt for nothing when they tried to pay me as it's a bit of fun for me anyway but they said they can't allow that and they'd give me a few sheep for my freezer for my efforts even if I don't find it but I'm sure if I find it they'll force me to take some sort of payment, I will try refuse as I really don't want it but it will be difficult to not take it when they're forcing it....
The paddock is about 3 hectares!!!!! Just over 7 acres so I really have a job ahead of me. The soil is extremely mild but it seems to have its share of junk. I assume rusty old nails and tractor bits and mower blades whatever else over the years.
Any help appreciated.
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