I wonder why the 13 kHz F75, the 19 kHz GoldBug Pro, the Nokta Impact @ 20 kHz and the 61 kHz Gold Kruzer all hit my micro jewelry test target to about the same depth????

Ever wonder about stuff like that? I do.

My F75 with the little 3x6 concentric will hit on my 3MM 10K white gold earring stud out to between 3/8" and 1/2" in JE and Boost mode. Put the Mars Lion 7" DD on and it will hit the crown of the stud out to 1" in Boost mode.

The GoldBug Pro with the 5" DD will hit the same target to the same depth at the F75, however the F75 has a more robust audio.

The Impact with the 4x7 DD coil in 20 kHz will hit the same target a little over 3/8". If I recall correctly, it does the same in 14 kHz.

The Gold Kruzer with the 4x7 concentric will hit the same target a little over 3/8" in Micro mode.

I wonder what the Gold Bug II results would be? Anyone know?


HH
Mike



Edited 1 time(s). Last edit at 12/13/2019 03:32PM by Mike Hillis.

I wonder about stuff like that all the time. The F75 wins with the “ more robust audio”, allowing you to find it in the first place. Signal acquisition to me is job 1. Interesting thinking here Mike..

Not so 'long ago I just went detecting, dug up some good stuff some junk stuff some iron stuff, ate my sandwiches drank my coffee admired the view then repeated digging stuff and went home and never thought about 'frequency!'

I always thought CZs with the 5 and 15 kHz had the best of both worlds.

I dunno. Just saying its weird that we put all this focus on high frequency for tiny stuff and I don't get any real performance gain when I go high.

HH
Mike

Put a low conductor in iron high freq will unmask it better. I can hit a deep silver in my test garden with 28kh and 54 kh... all though 14 kh hits it better. I run the higher freqs for relics as some of them fall in the low to mid range.....In my test garden the higher freqs hit gold better....especially if there is any iron present. According to the thinking in this thread then gold nugget machines might as well be 14 kh......which as we all know they are not and there is a reason for it....



Edited 1 time(s). Last edit at 12/13/2019 05:45PM by calabash digger.

I guess thats why detectors with multi freq like say the Equinox is so popular,it basically covers 'almost' all the freq's that you have mentioned from just one machine either individual freq or all together.Thats the winning trump card that Minelab hold !!

Mike-------If I remember correctly, Steve H. said he used the F-75 (13 kHz) for a lot of his gold (nugget) hunting in Alaska.-----Coming from him, that says a lot.----I believe the main reason he stopped using it when he moved to NV was because of the EMI problem with that detector (F-75).-----------Del

Why will some detectors hit that white gold earring and others will not.

I have the Orx w/ 9" hf, Deeptech Vista Gold, and Gold Kruzer. Gold Kruzer is the only one to hit it. The Orx has high frequency and will not hit it probably because the coil is to big. And the Vista Gold will not hit it with the 8x6. Again coil must be to big.

So there is a connection to coil size. Gold Kruzer hits best w/ 7.5x5 coil. Lobo ST w/ 5.75 no hit on it. Not powerful enough?

Maybe the lower frequency detectors that hit it have more power.

Mike...…. the 71Khz Gold Bug-2 should acquire your white gold stud earring to a few inches. This is it's specialty.

Thank you, Tom.

That was the information I was lacking. I'm doing all this bench marking (albeit with limited units) and getting the same results and was really scratching my head wondering what I was missing.

Ok...then. a Fisher Gold Bug II is in my future.

HH
Mike

The very best gold detector I have used for the money is the Nokta AU Goldfinder @ 56 kHz

This detector will hit on micro jewery that is off the chain.

I know because I test both detectors at the same time using the same targets.

I could not believe it. I sold the Fisher gold bug 2.

The AU Goldfinder was hitting on targets 3 to 4x the depth of the Goldbug 2.



Edited 4 time(s). Last edit at 12/13/2019 11:57PM by u2robert.

Most of the detectors I've used will hit small gold items when you air test them close to the coil, but the lower freq detectors would miss it when set on top of or an inch in ground.

My standard F75 with the stock 11 inch coil does very well on very small jewelry, (must dig low numbers) as I’m always finding stud earrings in the tot lots & other small jewelry. I have used other detectors with adjustable higher frequencies and just end up spending 30% of my hunt time digging pieces of chain link fence & other junk metals, where the F75 hated these junk Targets.

A lot of it just cant be determined until the coil hits the soil. Those depth at that point may well very a good bit....... then throw in EMI ....... or salt water. Even test beds can generally only tell us so much. We tend to assume a lot with say air testing. Then comes the target ...... compare two machines in the dirt or wet salt water. Find a coin..... then find a very low conduction with two machines. Make adjustments.... to both to get the best sound off the coin ..... only to find out you need to do it again off the low conduction. Thats why i have more than one machine .....even two of the same machines may react differently.

Some get snookered by air test results. And many detectors have been bought based on air test postings. Enter mineralization and a less than stellar target orientation and then differences will be witnessed. Laughable to see some folks comments when they say xxx model is finding the goods. What they don't know is what goods xxx model is missing.



Edited 3 time(s). Last edit at 12/14/2019 01:01PM by tnsharpshooter.

tnsharpshooter Wrote:
-------------------------------------------------------
> Some get snookered by air test results. And many
> detectors have been bought based on air test posti
> ngs. Enter mineralization and a less than stellar
> target orientation and then differences will be wi
> tnessed. Laughable to see some folks comments whe
> n they say xxx model is finding the goods. What t
> hey don't know is what goods xxx model is missing.


What really laughable is someone who thinks their detector
will miraculously go deeper in the soil than it will airtest?
So will mineralization, target orientation, soil conditions etc..
give you better depth. I think not.
If a detector can not detect a target in an airtest with not resistance
how will it detect deeper in soil with resistance?
Please Enlighten me on how you know what xxx model detector is missing or not missing?

General speaking as a coin hunter,,15 kHz and under is the best all around. Unless your specifically targeting small raw gold or like digging every piece of canslaw then anything past 15 kHz isn't really needed.Relic hunters may differ.
Multi frequency is ok for some I guess, but I find way to much to worry about what another machine might find that I missed.lol.
I still think the f75 is the best land machine made,Fisher got it right with that machine
Great thing about this hobbie is there's so many machines to choose from, what's best for others isn't always best for everyone .



Edited 2 time(s). Last edit at 12/14/2019 06:44PM by Woodbutcher.

u2robert Wrote:
-------------------------------------------------------
> tnsharpshooter Wrote:
> --------------------------------------------------
> -----
> > Some get snookered by air test results. And man
> y
> > detectors have been bought based on air test pos
> ti
> > ngs. Enter mineralization and a less than stell
> ar
> > target orientation and then differences will be
> wi
> > tnessed. Laughable to see some folks comments w
> he
> > n they say xxx model is finding the goods. What
> t
> > hey don't know is what goods xxx model is missin
> g.
>
>
> What really laughable is someone who thinks their
> detector
> will miraculously go deeper in the soil than it wi
> ll airtest?
> So will mineralization, target orientation, soil c
> onditions etc..
> give you better depth. I think not.
> If a detector can not detect a target in an airtes
> t with not resistance
> how will it detect deeper in soil with resistance?
> Please Enlighten me on how you know what xxx model
> detector is missing or not missing?

Doing head to head on targets in wild- same sites and on multiple days.
Even using same sized coils and sometimes smaller coils.

For instance.
Can Deus and using any sized LF coil find all nonferrous in my area that a Equinox 800 will locate (as nonferrous) ?
A big fat resounding NO !!



Edited 1 time(s). Last edit at 12/14/2019 07:09PM by tnsharpshooter.

u2robert Wrote:
------------------------------------------------
>
> What really laughable is someone who thinks their
> detector
> will miraculously go deeper in the soil than it wi
> ll airtest?
> So will mineralization, target orientation, soil c
> onditions etc..
> give you better depth. I think not.
> If a detector can not detect a target in an airtes
> t with not resistance
> how will it detect deeper in soil with resistance?
> Please Enlighten me on how you know what xxx model
> detector is missing or not missing?


For the same reason you can lose a local radio station 50 miles away, but pick up a radio station 500 miles away. Some conditions allow a radio signal to propagate better. Are you going to say that its impossible to get deeper targets in wet ground conditions? I hope not, because every single hunter I know has seen this happen. Its been discussed and confirmed since the first group of detectorists got together, but water is a signal absorber. It SHOULD be blocking our signals.

There are more than a few who have confirmed they have dug coins from measured depths, deeper than they can detect the same coin in air.

======================================================

You can see my videos here: [www.youtube.com]
My blog is here: [thesilverfiend.com]

======================================================

Robert...… the Tarsacci will indeed detect a target (I like to use a Nickel)….. deeper in wet-salt sand...….. better than my inert dirt test-garden...… and better than an air-test. It is the first detector (in history) that I have seen/witnessed such a large delta/difference...… as compared to any other detector. I can demonstrate this..... under nearly any atmospheric condition, weather condition..... and a host of other variables. It's really neat (and surprising).

I have seen my detectors go deeper in wet soil this is true.
But I believe the detector is just reaching it full potential in the wet soil.
where as the detector is not in dry soil the sane waves or EMF is being blocked
The sine waves just can not penetrate dry hard ground as well as it does
in wet soil just like digging in dry soil compare to wet soil.
IMO

I've never witnessed anywhere near air test depth, I'd say i reach 60%-70% of it in my soil, sand might be different?
Theres another manufacturer who claims their detectors go deeper in ground than in air, but their youtube video in my mind is flawed. They demonstrate the detector at it's low sensitivity setting, not it's highest, so it's not the detectors actual max air depth which is several inches more.

I think there are other contributing factors that are playing a role in your detector comparisons....transmit power, coil sizes and windings, filters, etc moreso than operating frequency. Otherwise, on detectors that feature frequency change but can keep all the other things the same, you can see a difference in the operating frequencies in regards to sensitivity to specific target conductors. The Whites V3i comes to mind as one of the forerunners with that ability, that also includes a signal strength bar for the 3 frequencies...the Minelab X-Terras with the different freq coils and in more recent machines such as the Nokta select freq machines, the Deus, and Minelab Equinox. On those machines, just cycling through to different frequencies will show you a big difference in signal strength and detection depending on what size and makeup the item is.

In some cases, having a detector specifically built around that operating freq platform will be better than one of the newer machines with select frequencies...even if they do have the same frequency. It's kinda like having a good Phillips head screw driver vs a multi tool that has a bit of everything on it. The multi tool can come in handy for a lot of different things but some times just a plain Phillips head screw driver is better.

Thanks everyone.

I understand operating frequency effect on larger, more conductive targets. I have no troubles there. Its just when I get into true micro jewelry (micro defined as tiny white and yellow gold and platinum jewelry items) that I was struggling. For some reason I thought high frequency was high frequency was high frequency. (with high frequency being defined as higher than 40 kHz). What I am learning is that not all high frequency detectors are equal, especially when any iron discrimination is introduced. I also know that if I can't get it in the air I'm not going to get it on the ground, not on these type of targets.

Also, yellow gold is much easier to detect than these tiny white gold and platinum items as it is much higher in conductivity, so while micro jewelry hunting is similar to nugget hunting in someways it is also quite different as the sensitivity needs to stay in place when iron discrimination is introduced.

It's been a larger learning curve than I expected.

HH
Mike

Mike Hillis Wrote:
-------------------------------------------------------

> It's been a larger learning curve than I expected.
>
> HH
> Mike


Learning to detect or run any detector model is fairly easy. Learning to master it can take years. Everything is a tradeoff and you have to do a ton of testing, swinging and digging to learn! At least its a fun learning process.

======================================================

You can see my videos here: [www.youtube.com]
My blog is here: [thesilverfiend.com]

======================================================

Yes it's crazy that the Gold Kruzer at 61khz can barely hit that white gold earring at 1/4". White gold has other metals in it like silver, copper, magnesium, zinc so what's the problem. Detectors hit all that.

The Gold Kruzer can hit on the tiniest targets but it's hard to get much of hit on that white gold earring. It doesn't make any sense.

It would be nice to see a list of detectors that can hit it and how deep. How about Whites 24k with the small concentric coil.

The primary alloy of white gold is..... Nickel.

Micro jewelry and micro nuggets are similar, with variations in natural gold running both smaller and less pure that eventually make many nuggets undetectable. Frequency is only one of many components, with circuit gain being a larger factor in many instances. Case in point the new digital 19 kHz Gold Bug does much better on small gold than the original analog 19 kHz Gold Bug. Gain can be pushed so high that many prospectors dumped the 71 kHz Gold Bug 2 for the highly boosted 45 kHz Gold Monster, which will air test better. Gain pushed so high leads to coil instability however that can prove problematic in field conditions so the equation becomes less clear in actual use. Coils matter a lot, concentric vs DD.

A huge difference exists when talking all metal vs discrimination. Machines that are better in all metal can drop behind other machines when the discrimination is engaged. It’s two different detectors really when talking disc versus all metal because there are different ways to approach discrimination at the micro level.

The efficiency of the ground balance circuit matters as sensitivity varies with the ground balance setting and so people in different ground see different results simply because they have different ground balance settings. Some detectors have discrimination ranges that run into the ground range, and opening that range can have dramatic effects, but with attendant issues in dealing with the ground and hot rocks

Then the dirty little secret nobody likes to mention or hear. At the micro gold level differences between individual detectors exhibit. No ten Gold Bug 2 detectors will test the same. There are good ones and bad ones. The GB2 is factory tuned for the coil it ships with. Merely changing coils can turn a good GB2 into a bad GB2. The coil design itself has changed over the years as has the Gold Bug 2 itself. Forum members here are probably aware of CZ differences. Well, the CZ has got nothing on the Gold Bug 2 differences that exist at the micro level, and it is far from the only detector for which that is true.

Once you sort all that out, the ground rules. Hot rocks nobody ever knew existed magically appear when running this class of detector to the hilt, and for micro jewelry the issue of micro aluminum raises its ugly head. In the real world practical limitations appear that air tests ignore. When you add all this up anyone thinking there is one magic detector that solves this equation best for all people.... good luck.





Edited 3 time(s). Last edit at 12/17/2019 06:20PM by Steve Herschbach.

I wouldn't think air testing on micro-jewelry would provide realistic real-world results, primarily because the eddies generated in micro-jewelry are so extremely weak that the main problem is disassociating such weak magnetic fields from all the conductive minerals in the soil. Which perhaps makes the real deal breaker the internal sensitivity of the electronics (which is unalterable) rather than purely a function of transmit frequency. If I had an assortment of gold detectors I'd test the earring stud buried in the ground at various depths and soil conditions and soil types. Might find results vary considerably from air testing. At least you'd know better which detecting tool to use for your respective soils. Would like to see those results!