What do Y'all think is more sensitive to silver dime's and smaller silver

KHz Wise?????? 4-8 KHz or 10-15KHz or 17-21.....I know what I see on the thinner silver in my dirt how bout You?

Just thin silver not quarter's on up....

Keith

The United States silver Half-Dime is the hairy-edge/turning-point of Khz. The 4-8Khz range parallels higher freqs on a half-dime. Now.......... a United States 3-Cent silver coin...... the higher freqs (marginally) win. Add mineralization..... and the equation changes yet another notch.

Hey Tom Interesting!!!

In my dirt I have my best luck on the small silver with the 17KHZ and up range...

I have always found it interesting that such a High conductor react's because of it's size to higher freq machine's better in my comparison's anyway...

1-Why is it that a High freq machine look's at smaller target's better?
2-Are Higher freq machines some how pushing more power to the coil or are they just more sensitive because of the freq ..
3- Can a super hot ( Tuned to the limit's of stability customized) say 4KHz machine resonate a silver 3-cent piece better than say a 19KHz machine factory stock like say a x-5 or GB PRO...coils being close to equal in size...

Some say Freq means little and some say it means everything....I am sort of middle ground on it but lean toward's freq for the items I am after in a hunted out spot...

I know in the last few year's with my sites drying up I sure do find more( Not at great depth's) with the Higher Freq detector's .....May just be me....

Keith

Hi, I'm finding the frequency range of 10-15 khz is pretty hot on thinner silver & brass items......On the other hand I have a detector that operates in the frequency range of 5-10 khz that is hotter than heck on gold........It don't make sense but if it's not broken don't fix it.......JJ

Keith, your #3 question is one that has been on my mind for quite some time.....and question #2 seems to be tied in.
Simply put, afaik, there aren't any "hot" tuned lower freq detectors on the market.
The closest we have had in the past is the ML Advantage/Musky.
Most newer detectors are higher freq. so nobodies got anything going on with the low freq.
Well....I suppose maybe the V3 could qualify if selecting the low freq but more than likely it is optimized for a specific freq.

So the questions could be rephrased something like this:
Can a lower freq high-gain detector be designed that will work well in trash, like the high frequency models?
With quick response/ recovery such as models of recent years?

Keith Southern Wrote:
-------------------------------------------------------
> Hey Tom Interesting!!!
>
> In my dirt I have my best luck on the small silver
> with the 17KHZ and up range...
>
> I have always found it interesting that such a
> High conductor react's because of it's size to
> higher freq machine's better in my comparison's
> anyway...
>
> 1-Why is it that a High freq machine look's at
> smaller target's better?
> 2-Are Higher freq machines some how pushing more
> power to the coil or are they just more sensitive
> because of the freq ..
> 3- Can a super hot ( Tuned to the limit's of
> stability customized) say 4KHz machine resonate a
> silver 3-cent piece better than say a 19KHz
> machine factory stock like say a x-5 or GB
> PRO...coils being close to equal in size...
>
> Some say Freq means little and some say it means
> everything....I am sort of middle ground on it but
> lean toward's freq for the items I am after in a
> hunted out spot...
>
> I know in the last few year's with my sites drying
> up I sure do find more( Not at great depth's) with
> the Higher Freq detector's .....May just be
> me....
>
> Keith


hi keith!
are you using the tek g-2 by chance?..thanks!

(h.h.!)
j.t.

1. OVERALL mass-conductivity. ((( A silver dollar has the same conductivity as a silver dime; YET, the overall mass differs greatly ))).
Silvers conductivity is '106'. (Copper is '100'.... the base-reference unto which all metals are electrically/conductively compared).

2. Higher freq units are (in general) more sensitive to smaller targets .... (almost) regardless of conductivity. Keep in mind........ the higher the freq.... the more the dirt will attenuate the EMF/energy.

3. In theory, if a lower freq (say 4-Khz) could be pushed out of a elliptical DD coil..... and with boost process clocking...... it would be hotter on small silver (Trimes). BUT..... a rule of physics enacts: that being, , , the lower the freq .... the more resistance to condensing this energy into a tight electromagnetic DD footprint. Imagine putting a lower freq into a wave-guide.

Dave Johnson defies (paradox) frequency 'stereotype'...... because he can take a higher freq unit..... and make it perform equally well on silver...... due to a 64X boost in Sensitivity.....utilizing this higher freq. It is fascinating to see how a T2/F70/F75 performs on a silver dime................ then............ see how a Whites V3 reacts to a silver dime. On the V3.... the lower freq nearly pegs the scale..... whilst the other 2 higher freq's can hardly see the dime.

I've air tested a silver dime with the four frequencies of the Deus. At 80 sensitivity, 8khz came in at around 11", 12khz was about 10&1/2", 4khz was slightly less, and 18khz was 10".

Hey Tom Thanks for the reply!!

Does deep silver on edge become a low conductor to a metal detector..... say a Morgan and 14 inches on edge.....


I know a Morgan lying flat at say 16 inches on a 4Khz 1266 machine should be seen in optimum condition's....Would a 1266 see it on edge at 14 inches??I am not sure it could?

I would almost bet an X-5 would see an Morgan at 14 on edge using the 19Khz....The 19Khz has really surprised me with on edge silver...did manage a SLQ @ 10 inches straight dead on edge...and a few Barber's on edge.....

Please understand people reading this...I am not trashing one machine for another I am just comparing Khz....They are both fine machine's...I believe the 1266 will see a belt buckle deeper in the ground when flat than a X-5......



That leads me to another question while I am on this particular subject........Why does a Higher freq Machine seem to struggle with large target's at depth...

I know My Lobo ST in a real world Hunt could barely hear a 12 inch U.S. boxplate lying flat...I actually thought it was a deep Bullet...I was digging a few right in the same spot and it was as weak or weaker than the .58 caliber bullet's...I have seen it many time's struggle with larger item's at depth a Blue & Gray or 12XX series would just jump on to quite easily.....
I know Tom stated and it is very true High freq get desensitized in bad ground but the large brass seems to struggle more than the smaller brass and lead at the same depth...


Things like this make you think the 14-15 Khz machine might be the best all rounder's .....Might be why the AT-PRO,,,,, Nautilus ,,,,,T-2 //F-75,,,,,MXT try to utilize this zone..........


Keith

No G-2 in use right now....I am using a Tejon for my HF rig right now with mixed result's....

Keith

Do you have any half dime's to test?Thanks for doing that Test for sure Bud..

I sure would love to get a Deus..Just for the specific's you just mentioned.....I could spend hours comparing signals in the ground with the different freq's...

I wish FT would offer us a Multi with the ability to turn freqs on and off in at least 3- 4 different freq's in a wide range....I know Dave J. stated the Bi-Axial is a broadband coil so it ought to be doable.....!!!

I say FT needs to build it because the Deus is built over sea's and warranty repair comes into play for me/us here in the state's....

The X-terras are nice with there 3 freq range but I believe they could of done more without the coil swap for freq and the response is way slow for this much technology .... come on!!!

Keith

It might have to do with the affect of minerals on one set of freq and EMI on anther. I dont think ive seen any where what freq the Minelab explorer/Etrac runs at .... im guessing around 3 kHz and it does well on deep silver and ive found a few paper thin silver dimes and 3 cent silver pieces. On a ML when you hit a Half.... it shows lower on the smart screen because of conductivity and it will dance left when on edge. Those thin dimes show up almost like an IH penny for me... somewhere around 07 24ish on the digital screen. We had some pretty rich farm dirt in Indiana as well Keith. Those 1/2 dimes in the middle of a field are hard to come by with all the minerals, iron, and hot rocks.

Dew

I feel dual frequency units excell and the proof is in the pudding as Explorers and CZ's sure are two of the best silver dime units around and get em deep so certainly would be my pick.

Technical lab specs do nothing for me as most are in lab settings, recently buried coins and air tests where in the field with thin silver buried for 100 years or so is where it counts.

Too many aspects in various ground and hunting conditions to even think about it as a fellow in Oregon may be facing a completely different scenario in Georgia and always heard low frequencies were for silver and high frequencies were for gold but its not always the case.

Opnions are like anal cavities and we all have one and just gave you mine in laymans terms.

I found my last half dime with my Explorer to bad it had a hole in it.

Keith Southern Wrote:
-------------------------------------------------------
> Do you have any half dime's to test?Thanks for
> doing that Test for sure Bud..
>
> I sure would love to get a Deus..Just for the
> specific's you just mentioned.....I could spend
> hours comparing signals in the ground with the
> different freq's...
>
> I wish FT would offer us a Multi with the ability
> to turn freqs on and off in at least 3- 4
> different freq's in a wide range....I know Dave J.
> stated the Bi-Axial is a broadband coil so it
> ought to be doable.....!!!

Unfortunately I don't have anything smaller than a dime to test. In the UK, 18khz is the popular frequency when searching for tiny silver "hammered" pieces, and they also seem to prefer it for areas of higher mineralization. One thing I've noticed which is kind of interesting, is that the conductivity scale is wider in the lower range (iron, foil, nickel) when using the higher frequency, and vice versa for the lower frequency. Makes certain frequencies better at id'ing certain targets.



Edited 1 time(s). Last edit at 09/14/2011 05:37PM by mrwilburino.

Tom your #3.....about a 4 khz being more resistant to being condensed....
So even though it may be harder to do....is it doable?

Agree with that Keith, if FT isn't working on a multi, the next best would be a selectable.
And please....keep the price down on it....those high ends are outrageous.

Interestingly I have found the F75 LTD in BP mode to be very sensitive to small brass and aluminum targets at depth, but not so much on small silver. It's also very hot on small gold.

Somewhere (wish I had a copy) is a Dave Johnson interview in which he states that operating frequency is no longer as important as it was in the past. That software is the main determinant these days as to how hot a detector is in regards to particular metal types.

mrwilburino Wrote:
-------------------------------------------------------
> I've air tested a silver dime with the four
> frequencies of the Deus. At 80 sensitivity, 8khz
> came in at around 11", 12khz was about 10&1/2",
> 4khz was slightly less, and 18khz was 10".


mrwilburino,

Which of the programs were your using? I ran a battery of air test on my Deus when I first got it but only on stock programs without modifications to any of the settings. I have a half dime and a three cent silver as well as V nickle, dime, quarter, half dollar, various Civil War bullets and buttons, and pull tabs (square and round) and bottle cap that I air tested. I also have both coils and on average the 13 inch coil is 2 to 4 inches better on air test than the 9 inch. Again that was just using default programs. My deepest coin find in the field was a an 1890 V nickle at about 8 1/2 inches. I believe I was using Dry Beach which is 18 Khz. (and the 13 inch coil) The soil had about 25 days of triple digits and was bone dry. Can't wait to get some rain and go back over the area.

Cuniagau

“Never approach a bull from the front, a horse from the rear or a fool from any direction.”

Yes.... a silver coin on edge drops down on the conductivity scale. . . . and yes...... subsequently...... a higher freq unit (in general) will detect this (perceived) lower conductivity target slightly better. Remember........... a coin on edge is just barely a sliver of metal to detect. Hardly a target. I'm not sure any detector will detect a silver dollar on edge...... beyond..... say 9" in dirt.

Keith..... a (normally medium conductivity metal)..... such as pewter or brass....... will look like a high conductivity target if it is large (snuff-tin/belt-plate size). This 'perceived' high conductor target will indeed be a bit more difficult for a higher freq unit to detect.

A interesting test is to use a F75 LTD/SE in 'cl' mode.......... and air-test it's ability on a tiny Type-1, U.S. $1.00 gold coin. Then.......... test a Double Eagle $20 U.S. gold coin. Run the highest Sens.... with the lowest Disc as possible. Your resultant will surprise you.

........... It is difficult......... but believe it is possible to engineer a lower freq unit to work well with a elliptical DD coil.

Thanks for the insight Tom!!

Medium conductor when large will be a higher conductor and high conductor's when small will be low conductor's.....I always had it in my mind a High silver Piece when small and on edge would read like a low conductor.....I seldom use meter's/or rely on them so ???

But the thing that blows me back is the medium conductor's when large being like High a conductor....Seems the surface area would help a lot on the ability see it...But I know for a field proven fact High Freq struggles on such item's....Not my first choice for deep plate hunting....

Again a real hot 14-15khz machine looks like it might be in the right range for multi purpose detecting...

On my testing I know the Omega with same coil (11" Bi-Axial) as Gold Bug will see large deep item's made of brass better than the Gold Bug....I have proven it to my self...

Anyone with a GB ought to really make use of a Omega as another tool for your site's...I think you will be quite surprised what the GB leaves on the deeper target's....they both use the same coil's and the compliment each extremely well.....

Thanks for all the input....

Keith

Cuniagau- sent you a PM.

There are some good technical articles available online written by the designer George Payne. One is titled 'George Payne on the Treasure Baron', in which he details natural resonant frequencies of targets, and how there is not one 'best-frequency' to detect them. In all-metal, the best freq. is the natural freq. of the target, but for good discrimination, a detector freq. a fair bit higher is needed.
Natural freqs of some US coins were quoted as: Silver dollar = 800Hz, dime(not sure whether silver or clad) = 2700Hz, nickel = 17kHz.

I am intending to do some natural frequency measurements myself for curiosity. I have some US coins (for comparison with George's figures) and will test a selection of U.K coins, older coins, jewellery, other items. Also I will note their target ID on an F75, for comparison.

Even a slight difference in freq, IE the MXT which runs a little under 14kHz and the DFX which you can use at 15kHz, can make a difference in depth. I understand the inner workings of these machines are different and the ability to set up the DFX really comes into play. But there are advantages to the MXTs lower freq. Some of the comments of what various conductivity targets do and really be seen on an Exp. smart screen at depth.

Dew

Yes......... there's a world of knowledge to be gained by George Payne's silver coin test. 0.8-Khz for a silver dollar.... and 2.7-Khz for a silver dime.
They are both identical silver (.900 silver)............yet.......... the resonant response is dramatic between the two coins.

...... Then..... enter the nickel !!!


This is one of the reasons why a TRUE multi-freq unit will perform better. Life is so short............ its extremely inefficient to have to swing multiple detectors (each of different operating frequency) over a hunt-field...... so as to ascertain maximum 'target resonance' for each item. Lest we interject geophysical additional err: Masking, Silent Masking, Too Deep, On Edge..........etc.............

I believe Minelab's FBS technology has pretty well solved the fixed frequency issue. They transmit square waves into the ground causing a wide spectrum of harmonics. (Hence their claim of 1.5 to 100khz operation) My speculation is that they sort out the magnitude of returned signals at specific frequencies (much like a Spectrum Analyzer) and assign values according to where the target's returned signal falls in the spectrum. Single frequency detectors only measure the phase shift of the returned target's signal compared to the transmit signal to determine a conductivity value.

Minelab has done a good job, but the equipment only transmits 29 RANDOM freqs per channel. Then my understanding is they use the stronger 2 with an additional for GB. The issue i have is the random freqs. and not knowing what each are per channel. I believe random means.... not set like on the SOV at 1.5 kHz increments. So they are set in each channel.... that would be good info to know since various channels may allow for better choice in certain areas. I think there are improvements yet to be made.

Dew

TerraDigger Wrote:
-------------------------------------------------------
> Somewhere (wish I had a copy) is a Dave Johnson
> interview in which he states that operating
> frequency is no longer as important as it was in
> the past. That software is the main determinant
> these days as to how hot a detector is in regards
> to particular metal types.

This seems to (in some instances) be true.

My AT Pro is a higher frequency then my F75 LTD and it hits on silver dimes deeper.....amazing for a machine half the price with a higher frequency

Turn the tables, and I'm certain the LTD will detect deeper then the AT Pro on deep gold.

Funny you mention the AT Cal,...The Garrett sure does act like a lower freq machine ....it loves coins and is just average on low conductor's.....Almost seems like the 14-15 Khz range is the breaking point...........They can offer hotness across the board in this range or can be tuned one way or the other...but get above or below this freq and the Khz starts to play into it more so .......

The At does offer alot for the price point it's at.....

Wonder what the Gold will do?I have a feeling it will be weak on coin's......

I do like the looks of that new coil though!!

Keith

Just to interject something here...

It totally makes logcial sense that a high conductor would, when on edge, "hit" like a lower conductor.

However, this is not my experience with my Minelab Explorer. A penny which is "on edge," or even one "bent" by a lawnmower and thus which will show a smaller surface area, will actually read HIGHER -- so as to mimic a silver dime. Don't know why, but this is the case.

Steve