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Which Frequency Is Running In Each Mode?


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You've done a lot of work and thank you for that.  But could you show these data in a table?  If possible show the composition and diameter (where applicable) for each coin.  It appears that between the two frequencies, some got better ('deeper') some got worse ('shallower') and at least one stayed almost the same.

I can't speak for others but I never would have guessed that a 98.6% purity gold coin that is slightly smaller than a 1 ozt 99.9% silver round would win this competition convincingly, and at both frequencies!

Once again I'm reminded that simple explanations don't capture the entire picture and one needs to be careful making generalizations, at least expecting those generalizations to cover all situations.

Now I wonder if this has anything to do with recovery speed.  Is the phase shift for the silver round later than for the large gold coin?  If so is it possible that the silver round signal is truncated, affecting the reported signal amplitude?  (Just talking off the top of my head, in case you didn't notice.  😄)

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17 hours ago, GB_Amateur said:

You've done a lot of work and thank you for that.  But could you show these data in a table?  If possible show the composition and diameter (where applicable) for each coin.  It appears that between the two frequencies, some got better ('deeper') some got worse ('shallower') and at least one stayed almost the same.

I can't speak for others but I never would have guessed that a 98.6% purity gold coin that is slightly smaller than a 1 ozt 99.9% silver round would win this competition convincingly, and at both frequencies!

Once again I'm reminded that simple explanations don't capture the entire picture and one needs to be careful making generalizations, at least expecting those generalizations to cover all situations.

Now I wonder if this has anything to do with recovery speed.  Is the phase shift for the silver round later than for the large gold coin?  If so is it possible that the silver round signal is truncated, affecting the reported signal amplitude?  (Just talking off the top of my head, in case you didn't notice.  😄)

 

....The purpose of this test was to find out how different detectors cope with high-conductivity coin type targets for deep detection... I recently had the opportunity to buy a CTX 3030 with a standard 11" coil and a large 13x17" coil at a very good price after tests on my test field where I have it buried higher a medium-conductive 50 euro cent coin at 37 cm with good results, I was curious how the test detector would cope with the other detectors I currently have with me Equinox, CTX, Atrex and ORX in tests for gold and high-conductivity silver coins... and high-conductivity Roman AS../coin/

Of course, I expected that the range of the CTX *3030 detector would be the greatest right on highly conductive coins... but as it turned out... the greatest range was right on a large 40 mm -14 gram 24 gold coin..

that surprised me a bit and that's why I tested the Equinox similarly on the multi programs Park1 and Park2 ... also on one frequency 4khz, 5khz, 10khz, 15khz, 20khz and 40khz...

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 test CTX 3030 :

In this test, it is nice to see that the thick highly conductive Roman AS coin has a significantly smaller range than the large gold coin of 4 ducats...

during the CTX test, I used the Coin program and sensitivity 20, 22, 23, 24, 25 to see how the range of coins changes with sensitivity...coin reach is measured in centimeters....

IMG_20230120_205202 (2).jpg

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Test Equinox 800

On the Equinox  800 test, it is also nice to see how the reach of individual coins differs from the used 1 frequency.., the multi-frequency balances these differences more..but it is still clear that the highly conductive Roman AS has a smaller range than a large gold coin..coin reach is measured in centimeters....

v you can see the significant differences in range between one frequency 4 khz and 40 khz on large gold coins 4 ducats and Roman AS... where the difference in range is up to 30%!!!

setting  "recovery speed 3 ,iron bias 0, sens 20..

IMG_20230120_205523 (4).jpg

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The optimum frequency for any target is when that target has a 45° eddy response. That is where the R-channel response is maximum, and that is the channel used for raw detection.

Most likely 4kHz creates a stronger response for the gold coin because its response is closer to 45° and it's roughly the same physical size as the dollar coin. If you could set the frequency to 1kHz you would likely be at the peak of the dollar while the gold coin is lower.

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Carl... Thank you for this information.. it is very valuable...👍🏆..

Just... the main motivation... for my testing was to find out whether today's modern detectors are really sufficiently optimized for large highly conductive coins... because a difference of 7-8 centimeters in range represents "several times stronger signal response" .. for a large gold coins... vs.. an equally large Silver Dollar coin ..
 ... But it can be seen that there are still reserves in the use of really low working frequencies somewhere around 1 Khz to 1.5 khz... which could be successfully used to detect deep signals... highly conductive coins...

my CTX3030 multifrequency measurement:, the lowest used frequency of CTX is 3.3 khz and the highest used frequency is around 25 khz

IMG_20230120_203102_287.jpg

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The ultimate deep silver detector would run at 1kHz. The lowest frequency detector I can name off-hand is the old White's Coinmaster V, it ran at 1.75kHz. I seem to recall something ran at 1.25kHz but can't say what it was. For more modern models, the V3 runs at 2.5kHz, the 1280x runs at 2.4kHz, and BBS/FBS/CTX runs at 3.125kHz (and 25kHz).

 

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I did the following CTX test on a large 13x17" large coil.. in the Coin program at sensitivity 20... which was aimed at comparing the range between high-medium conductive/a large 24K gold coin the size of a silver dollar and a 50 euro cent - the size of a silver quarter/ .....and highly conductive silver Coins of various sizes.. such as Dollar, Half Dollar, Quarter dollar, and American silver Dime...
 
I supplemented this test with 2 low-conductivity targets: a 5-gram gold stater - made of an alloy of gold and silver/electrum/ and an American 5-cent nickel coin..

 

IMG_20230122_171710 (2).jpg

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1 hour ago, EL NINO77 said:

I did the following CTX test on a large 13x17" large coil.. in the Coin program....

Are you able to do a Fast Fourier Transform (FFT) analysis on this mode of the CTX?  My recollection from reading Candy's mongraph is that the FBS2 (and FBS) doesn't use the same signal generation as other multifrequency detectors so maybe it's not so simple to determine as it is on the Equinox?

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GB_Amateur...        yes, you are right... to measure the actual working frequencies of multi-frequency detectors, I use an oscilloscope with the possibility of measuring with the help of FFT, on the condition that you measure the actual TX current of the test detector, and not the TX voltage... of the detector... this is how you get the truth information about the frequencies at which the multi-frequency detector really works.

In this way, you can even compare quite accurately, for example, how Etrac and CTX work on their different channels 1-11/ shift of working frequencies in multi-frequency .. where you will find that the difference of the highest frequency between the lowest channel 1 and the highest channel 11 is at the upper working frequency of up to 5 khz.. /23khz vs 28khz/..
and that's why the opinion of some detectorists... who claim that channel 11 is the most sensitive to small gold... can be true.

 

....And now to the test itself, where I wanted to check one thing and specifically that... it seemed to me that the CTX in some field depth tests on the test field that I know... had a better range on the 50 euro cent coin at 35 cm... than on a similar size.. silver coin at the same depth...

  

On the test image..blue marked 50 euro cent, gray marked silver coin... similar and the same size as 50 euro cent...

InkedCTX 3030 test ...jpg

 

.....This matches my colleague Mike's tests....on his test field for these coins..

silver coin at depht 35cm

 

50 eurocent a depht 35cm

 

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