Gold coins detection

[Geo]

The reason why I asked about other metals, humidity, and AC power is to determine if there is any possibility of electrically conductive ground. This seems to be the case. With conductive ground and grounded AC power, it is well possible that some ground fault induces currents in the soil. Under such circumstances, all sort of strange things can happen. For example, once I plugged in an old refrigerator, standing on the wet soil, out in the garden. It rattled a bit but seemed to be working OK. However, it drove all earthworms within meters, out of the soil within minutes. Funny to see the soil becoming alive. Touching the refrigerator did not give any electric shocks, but there must have been some stray current into the moist soil that made the worms want to leave their home in a hurry.

The gold coins are the most noble metal in the ground. If the humidity penetrated to the gold coins, there is an electrolyte connecting the other metals nearby. This produces a voltaic cell and a magnetic field surrounding the current flowing between the more noble metal and the less noble metal. This could possibly be some zinc coated iron water pipe. The voltage of this cell could be over 2 volts.
Many times in old houses, the "AC Earth" was connected to such iron water pipes, being the best available AC Earth available. Any electrical ground fault in the house would then generate currents in the pipe.
With the gold coins recently buried and dry, there would be no connection.
After some time, when the electrically conductive water has penetrated to the gold coins. The situation has become dramatically different.
This is just speculation, but, if I was there, it would be the start for trouble shooting.

I have never seen a LRL that did not work on the dowsing principle. If it does exist, I would be very interested to see a schematic. If you have a schematic, please post it in the LRL forum section, as I would love to build it.

Hi Tinkener. I will try to convince my friend to dig and take out the coins so to see at who conditions they are.
If i"ll take them out i" take a photo and post here.
About the LRL if you like come to longrangelocators so to discuss it.

Regards

[Tinkerer]

Hi Tinkener. I will try to convince my friend to dig and take out the coins so to see at who conditions they are.
If i"ll take them out i" take a photo and post here.
About the LRL if you like come to longrangelocators so to discuss it.

Regards

Proof for my theory above, will be that the gold coins are dirty when recovered. The dirt coating may not necessarily be sticking to the coins.

[Geo]

Proof for my theory above, will be that the gold coins are dirty when recovered. The dirt coating may not necessarily be sticking to the coins.

after 2..3 weeks we will know

[Tinkerer]

after 2..3 weeks we will know

Good, this may also be a good way to explain the whole "halo" enigma.

[chemelec]

All coins have a "natural" frequency at which they will generate a maximum R signal on a VLF metal detector. George Payne analyzed this many years ago and determined that some of the US coins had the following results. A dime and penny were about 2.7khz, while a silver dollar was down at about 800 hz and a nickel was at a frequency of about 17khz. Fine gold and thin gold rings had a natural frequency that was quite often higher than the nickel. I believe George was using one of his 6.59khz units when he made his determinations.

Is this really a function of the metal content, or partly a function of the SIZE?
Also I believe that the Metal Content has changed over the years.

In Canada, Most Quarters, Dimes and Nickel coins are Nickel, But some of these coins have even been made of Stainless Steel.
Our Pennies are Copper, Unlike the US ones which I believe are Copper Plated Zinc.

[Geo]

Ohhh... Gary, so many years to read from you!!
Happy new year

[Tinkerer]

Is this really a function of the metal content, or partly a function of the SIZE?Also I believe that the Metal Content has changed over the years.In Canada, Most Quarters, Dimes and Nickel coins are Nickel, But some of these coins have even been made of Stainless Steel.Our Pennies are Copper, Unlike the US ones which I believe are Copper Plated Zinc.

Hi Garry, long time no see! I wish you a very happy new year.

Let's talk about non magnetic coins first.The 2 main factors in the response signal of coins, are size and TC.

The size of the target gives the amplitude of the response.
The TC of the target defines the amplitude of the response that is left after a certain time after TX.

The Size is related to the surface area as seen by the magnetic field lines of the coil. A large coin in the vertical position may present a small area and will therefore have a low amplitude response. A small coin presented flat to the coil, may offer a larger area in this position and give a higher amplitude response.
When we measure the signal response some time after the end of the TX, the TC, or Time Constant of the coil becomes very important.

We can look at the US Nickle and the US Dime as good examples.
The Dime is very much smaller than the Nickle, but, due to small differences in nickel content it's TC is about 5 times longer.
The Nickle is larger and therefore will give a high amplitude response during and right after TX. But with a TC of about 10us the decay of the signal is fast. Taking our sample at 20us after TX, the signal amplitude has diminished to about 15% of it's original amplitude. At this time, The Nickle may appear to have a smaller response than the Dime.

[chemelec]

Ohhh... Gary, so many years to read from you!!
Happy new year

I am on this site Almost every day.
I just don't post very often.

Happy New Year to you also.

Gary

[Davor]

Regarding funny coins, it seem to me that we'll see much more bad coins in near future as the cost of real materials go up. Seigniorage is a term for difference between cost and face value of a coin, and to keep up with the cost many countries are minting their coins with cores of junk material. Croatian currency is Kuna, and smaller tokens are Lipa. While cost of minting 1 Kuna coin is ~3.5 Kuna (ridiculous, negative seigniorage), smaller Lipa coins' cost is reduced by using a steel core. Guess what - I keep my Lipas together with a small neodymium magnet. They produce a very funny rattling sound with my VLF detector.
Euros are also produced in layered fashion.
Funny thing is that all olden money including late Yugoslavian Dinar give pristine clear sound even for the smallest tokens.

[chemelec]

Hi Tinkerer, Thanks for the info, and a Happy New Year to you and your familyalso.
Also to Davor, A Happy New Year to you and your family

In Canada, our Penny will be Obsolete in March of this year.
Everything will be Rounded to the nearest Nickel.
Besides, What can you buy for a Penny anyway.

Our $1 is a coin called a "Loonie" and our $2 is also a Coin called a "Toonie".
Both are "Heaven Only Knows as to What Metal or Metals are in them".

[multieagle]

This may have been previously posted:

Best frequency to use:
US Dime = 2.7 KHz
Gold Coins & other US Coins = below 10 KHz.
Us Nickel & gold Jewelry = 16.5 KHz
Gold Nuggets = above 20 KHz
---------------------------------

Metal Detectors based on Operating Frequency

Blisstool LTC64X v3...........Base operating frequency: v3 - 8.0 KHz
Adjustable operating frequency (+/-60Hz)
Bounty Hunter Land Star............6.6kHz
Bounty Hunter Lone Star............6.6 kHz
Bounty Hunter Pioneer 505........6.8 kHz
Bounty Hunter Quick Silver.........7.0 kHz
Bounty Hunter Texas Pilot...........7.0 kHz
Bounty Hunter Time Ranger.......6.9 kHz
Bounty Hunter Tracker IV............6.6 kHz
DeepTech Vista Gold................25 kHz
DeepTech Vista Smart.............15.5 kHz
DeepTech Vista Rebel ..............8 kHz
Discovery Treasure Baron.......12.5 kHz
Fisher 1266-X.............................4.8 kHz
Fisher 1270x...............................8.2 kHz
Fisher 1280-X 8" Coil................2.4 kHz
Fisher CZ-21 10" Coil.............5,15 kHz
Fisher F2.....................................5.9kHz
Fisher F4.....................................5.9kHz
Fisher F5.....................................7.8kHz
Fisher F70.................................13 kHz
Fisher F75.................................13 kHz
Fisher Gemini-3........................82 kHz
Fisher Gold Bug I......................19.2 kHz
Fisher GoldBug II 6.5" Coi........71 kHz
Fisher GoldBug II 10" Coil........71 kHz
Fisher Quicksilvers (CZ-5, CZ-6a and CZ-20) operate on two frequencies — 5 kHz and 15 kHz
Garrett Ace 150...........................6.5 kHz
Garrett Ace 250...........................6.5 kHz
Garrett Ace 350...........................8.25 kHz
Garrett AT Pro............................15 kHz
Garrett AT Gold..........................18 kHz
Garrett Deepseeker.................... 5.5 kHz
Garrett Gold Scorpion.................15 kHz
Garrett Groundhog.....................15 kHz
Garrett GTA..................................6.5 kHz
Garrett GTAx_500.......................7.0 kHz
Garrett GTI 1500..........................7.2 kHz
Garrett GTI 2500..........................7.2 kHz
Garrett GTP 1350........................7.2 kHz
Garrett Infinium Land & Sea.......730 pps
Garrett Treasure Ace 300...........6.4 kHz
Minelab E-Trac............................1.5-100 kHz
Minelab Excalibur II - 8" Coil.......1.5-25.5 kHz
Minelab Excalibur II - 10" Coil.....1.5-25.5 kHz
Minelab Eureka Gold...................3 frequency (6.4kHz, 20kHz, and 60kHz)
Minelab Explorer SE Pro............28 different frequencies, from 1.5kHz to 100kHz
Minelab Musketeer Advantage Pro...5kHz
Minelab Quattro MP.....................28 different frequencies at once, from 1.5kHz to 100kHz
Minelab Sovereign.......................BBS - 17 different frequencies at once, l.5 kHz to 22.5 kHz
*Minelab Sovereign and Excalibur operate over a broad range of frequencies (2 - low of l.5 kHz to 22.5 kHz — 17 individual frequencies simultaneously.
Minelab X-Terra 70....................(VFLEX compatible) Coil Frequency Options......3 (Standard 7.5 kHz, Low 3kHz, High 18.75 kHz)
Minelab X-Terra 305....................2 (Standard 7.5kHz, High 18.75kHz)=(coil frequency options)
Minelab X-Terra 505...................3 (Standard 7.5kHz, Low 3kHz, High 18.75kHz)=(coil frequency options)
Minelab X-Terra 705....................3 (Standard 7.5kHz, Low 3kHz, High 18.75kHz)=(coil frequency options)
White's Beach Hunter 300..........(Multiple Frequency)
White's Coinmaster Pro..............8 kHz
White's Coinmaster GT...............8.192 kHz
White's E-Series DFX 300.........3 kHz, 15 kHz, or use both frequencies
White's Goldmaster GMT..........50 kHz
White's Gold Master Vsat.........50 kHz
White's M6 Matrix Series..........15 kHz
White's MXT 300........................14 kHz
White's MXT Pro........................14 kHz
White's Prizm 5G.........................8 khz
White's Prizm 6T..........................8 kHz
White's Sierra Madre..................6.5 kHz
White's SL series........................6.59 kHz
White's Spectra V3i....................2.5, 7.5, 22.5 kHz
White's Spectra VX3..................2.5, 7.5, 22.5 kHz
White's Surf PI Dual Field..........800 pps ?
White's XLT..................................6.5 kHz
Teknetics Alpha..........................7.8 kHz
Teknetics Delta 4000..................7.8 kHz
Teknetics Gamma......................7.8 kHz
Teknetics Omega.......................7.8 kHz
Teknetics T2..............................13 kHz with frequency shift option
Texas Titan 9000........................6.6 kHz
Texas Titan 9000 Pro.................6.6 kHz
Texas Titan 9000 Pro Plus.........6.6 kHz
Tesoro Cibola............................14.3 kHz, 14.5 kHz, 14.7 kH
Tesoro Compadre.....................12 kHz
Tesoro Cortes............................10 kHz
Tesoro DeLeon..........................10 kHz
Tesoro Golden uMax.................10 kHz
Tesoro Lobo...............................17.5 kHz
Tesoro Sand Shark.................600 pps
Tesoro Silver Sabre µMax........10.6 kHz
Tesoro Tejon..............................17.2 to 17.6 kHz
Tesoro Tiger Shark...................12.5 kHz
Tesoro Vaquero........................14.3 kHz, 14.5 kHz, 14.7 kHz
XP Deus....................................4,8,12,18 kHz

PINPOINTERS

VLF

Falcon Metal Detector - Pinpointer/Probe............300 kHz
Garrett Pro-Pointer........................................... ..12 kHz
Garrett SuperWand Pinpointer.............................95 kHz
Minelab PRO-FIND 25..............................................?
Treasure Mate Pinpointer...................................16.5 kHz
Treasure Gold Hunting Pinpointer Metal Probe.....105 kHz
TX-2002 Dual-Use Pinpointer...............................90 kHz
Whites Bullseye II Pinpointer................................36 kHz

PI
DetectorPro UniProbe
Detector-Pro Pistol Probe..... Adjustable pulse timing
Vibra-Probe 570
Vibra-Probe 580
Vibra-Tector 730
Vibra Quatic 2

to add/research
Automax Precision v2,v4,v6...................?
Cen-Tech pinpointer.....................?
Compass Auto-Max......................?
CP-100 Coin and Cache Probe.......?
Depth Master Super Probe............?
Fisher F-Point pinpointer...............?
Little Wizard probe.......................?
Merlin pinpointer..........................?
Teknetics Pinpointer.....................?

2 Box Metal Detectors
Fisher Gemini-3......................82 kHz
White's TM 808.......................VLF (Single Frequency)

[Carl-NC]

Corrections:

Minelab pinpointer: 13.3kHz
Minelab BBS & FBS detectors: 8.125 & 25 kHz
White's BHID: 3 & 15 kHz
White's TM808: 6.592kHz
White's Surf PI: 600pps
White's M6: 14kHz

[multieagle]

Thanks.