Impact ID numbers - chart

[Bill_S]

Sorry, made a mistake on the chart. Will upload once I get it fixed.

 

[Bill_S]

[attachment 341590 ids.JPG]

 

[squirrel1]

Good work Bill,,,thanks for sharing.
Numbers look like what I'm getting.

 

[Bill_S]

Thanks.

 

[Monte]

I used two silver Half-Dimes, an 1838 Capped Bust and 1854 Seated Liberty, and came up with the following results. This was using V.1.08:

In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had '65' @ 5 kHz, '82' @ 14 kHz and '83' @ 20 kHz. The Normalized VDI was '82'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had '42/43' @ 5 kHz, '66/67' @ 14 kHz and '72' @ 20 kHz. The Normalized VDI was '67'

Almost all my other US coin samples were similar to yours, the only exceptions being the oddball coins that had a poor mixture, such as an 1871 Seated Liberty 50¢ piece in very nice condition, but the TID read-outs are about 3# below what most silver halves read.

Just curious if your results were with a different software version or rad off a wrong line of notes. Check again, if you would.

Thanks,

Monte

 

[Bill_S]

Thanks Monte. I may have to get some older coins to test with. I only have the usual.....;o)

 

[Bill_S]

Your tests

In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had '65' @ 5 kHz, '82' @ 14 kHz and '83' @ 20 kHz. The Normalized VDI was '82'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had '42/43' @ 5 kHz, '66/67' @ 14 kHz and '72' @ 20 kHz. The Normalized VDI was '67'



My tests with an 1854 half dime. I done mine indoors so it may have had a bearing on it plus I was in 90 for the GB.


In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had '58' @ 5 kHz, '76' @ 14 kHz and '82' @ 20 kHz. The Normalized VDI was '82'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had '33' @ 5 kHz, '58' @ 14 kHz and '67' @ 20 kHz. The Normalized VDI was '58'

 

[Monte]

Monte's tests, indoors, Gain setting s of '90' to '99' depending upon mode used. I used an 1836 Capped Bust Half-Dome and a very worn 1854 Seated Liberty.

In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had '65' @ 5 kHz, '82' @ 14 kHz and '83' @ 20 kHz. The Normalized VDI was '82'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had '42/43' @ 5 kHz, '66/67' @ 14 kHz and '72' @ 20 kHz. The Normalized VDI was '67'



My tests with an 1854 half dime. I done mine indoors so it may have had a bearing on it plus I was in 90 for the GB.


In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had '58' @ 5 kHz, '76' @ 14 kHz and '82' @ 20 kHz. The Normalized VDI was '82'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had '33' @ 5 kHz, '58' @ 14 kHz and '67' @ 20 kHz. The Normalized VDI was '58'

Bill, I was tired the past two nights when I tried to budget time to work on the charts for coins, so I gathered up my notes early this morning about 6 AM and double-checked them all. I e-mailed Dilek with results I got from OLDER USA COINS, and let her know that on all the modern coins you sampled, my results were almost exactly the same. Therefore I didn't send her my modern coin or common silver coin results, and instead did a cut-and-paste of the very nice job you did on your chart.

* NOTE #1: Our numbers differ for the Half-Dimes. I noticed you listed the 'Normalized' VDI for the 7 Relic Hunting modes as '82', however your 14 kHz listing (which should be close to the 'Normalized' read-out) was '76.'

My earlier Coin Read-outs were done using the standard 7X11 DD coil, but I headed into town today with the 4X7¾ DD coil mounted on my Impact, so I used that coil to double-check the readings after I got home and read your reply. So, I located the older era coins I have on-hand and sat down to double check the numbers. Here are the results I had for some older coins as I sent to Dilek, and my current results are the same as I had earlier.

* NOTE #2: The Half-Dimes I used were an 1836 Capped Bust, and another one I used earlier was a well worn, barely identifiable 1854 Seated Liberty. I used the fuller detail Capped Bust again to confirm my TID read-outs, and again they differed from yours. Checking, I noticed the 1794 thru 1836 Half-Dimes were made of 89.[size=small]24[/size]% Silver and 10.[size=small]76[/size]% Copper, but in 1837 [size=small](the last year for the Capped Bust and first year for the Seated Liberty)[/size] they changed the mixture to 90% Silver and 10% Copper. That's a very minimal change, but it could be that the earlier 1836 Capped Bust I had found could have had some poorer quality metal mixture, which has happened. Just the way most 1864 to 1909 Indian Heads and most early Wheat-back Cents have a lower numeric TID that is similar to the modern Zinc Cent, even though their mixture was supposed to be the same as most of the better Bronze Cents made during that period and on thru 1980 and part of 1981.

Anyway, here are some Old US Coin TID read-outs I got with the Impact:

Monte's Tests: Impact w/V. 1.08 update. 'Relic Hunting modes Gain of '90' to '95' and Coin Hunting modes Gain of '95' and '99.'
Tests done indoors as well as out in my dirt-floor wood shed/test garden area.


I used an 1858 Flying Eagle Cent.
In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had:
'Standard' '52/54' @ 5 kHz ... '65' @ 14 kHz ... '71/72' @ 20 kHz
'Normalized' VDI was '65'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had:
'Standard' '25' @ 5 kHz ... '42' @ 14 kHz ... '53' @ 20 kHz
'Normalized' VDI was '42'


I used an assortment of 8 Indian Head Cents from 1880 thru 1906, and about 12 or 13 Wheat-back-Cents from 1909 to 1920.
In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had:
Most are lower reading and similar to the modern US Zinc Cent, and numbers in each category could be ±1 to 2 numbers to a Zinc Cent.

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had:
Most are lower reading and similar to the modern US Zinc Cent, and numbers in each category could be ±1 to 2 numbers to a Zinc Cent.


I used an 1865 'Nickel' type 3¢ Piece.
In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had:
'Standard' 49' @ 5 kHz ... '49' @ 14 kHz ... '50' @ 20 kHz
'Normalized' VDI was '49'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had:
'Standard' '18/19' @ 5 kHz ... '21' @ 14 kHz ... '25' @ 20 kHz
'Normalized' VDI was '21'


I used an 1836 Capped Bust Half-Dime and 1854 Seated Liberty Half-Dime.
In the 7 'Relic Hunting' modes with a Ferrous/Non-Ferrous break-point of '40' I had:
'Standard' '65' @ 5 kHz ... '82' @ 14 kHz ... '83' @ 20 kHz
'Normalized' VDI was '82'

In the 5 'Coin Hunting' modes with a Ferrous/Non-Ferrous break-point of '15' I had:
'Standard' '42/43' @ 5 kHz ... '66/67' @ 14 kHz ... '72' @ 20 kHz
'Normalized' VDI was '67'


All of what we are doing is trying to help the inquiring consumers with information about the new Nokta Impact. In doing so, one of the things we need to keep in mind, here in the USA or in any country is that when it comes to Coin read-outs there can be many variables that can, and will, influence what audio and/or visual response we might get. Coins that are too deep to properly register, or they are on-edge or canted, maybe too close to some other metal that partially masks it or that causes a 'blended' response.

Some coins could be made out of slightly different alloy mixes, or the alloys used might not have been as 'pure' or 'refined' and they were at other periods of time, or the source of the metal, such as copper ore, can make a difference in quality or purity. We also can not forget that some coins or other anticipated targets might be worn thinner, damaged or altered such that their response might be different from the normal response.

Therefore, although we have all the nifty displays and tones and adjustment features to use for our choice of metal detecting adventures, the fact remains that there is no 'perfect' metal detector, nor is there always going to be a 'perfect' site environment and target response. That's why my personal approach is, and has been for decades, to use the least amount of Discrimination I can tolerate, the most Gain I can handle w/o instability, pick the best search coil suited for the site conditions and amount of debris present, then use a slow and methodic search of the site, making sure I very effectively overlap my sweeps and recover all targets that produce a good or reasonably questionable iffy response.

Monte

 

[Bill_S]

Thanks for the info on the coins. Here is a picture of the half dime I was using to test. It was found in a place with some civil war activity.

[attachment 341650 halfd.jpg]

 

[Stoof-tabsallday]

Since I don't know all the features and modes yet, what does the chart mean, "normalized ID"?
I see the top one shows that the lower the conductor the bigger difference between frequencies. Is that a separate mode for normalized?
Thanks and sorry, they don't have a manual yet that I can read to get to know it.

 

[squirrel1]

Since I don't know all the features and modes yet, what does the chart mean, "normalized ID"?
I see the top one shows that the lower the conductor the bigger difference between frequencies. Is that a separate mode for normalized?
Thanks and sorry, they don't have a manual yet that I can read to get to know it.

Okay,
Impact can be run in normalized vdi setting,,,which means every frequency used ideally the same targets swept will read same vdi.
And the meter readings achieved here will be based on how a target reads in 14khz (using not normalized)

Whereas using non normalized setting,,,,vdi numbers will read differently dpending on which freq is used at time of detection.

For example a quarter will read highest vdi using. 20 kHz.
Switch to 14khz quarter will read lower than using 20khz.
Switch to 5khz quarter will read even lower than using 14khz.

And the chart above (second one) reflects all this info.

 

[Cal_Cobra]

Bill thanks for doing the tests.

Are you planing to release some kind of air test/depth chart with both coils from the Pro Pack?

Thanks!
Cal

 

[Bill_S]

Are you planing to release some kind of air test/depth chart with both coils from the Pro Pack?

I have not done one but I will see what I can do.