Coil separation testing?

[WV62]

Trying to come up with a way to test for best target separation between coils.

I tried one test by laying a wooden yard stick on the ground and placing a dime and small nail on the yard stick. Started off with like 3" of separation and keep moving closer until the nail started messing with the coin signal.

Problem with that is all my coils came in really close to the same amount of separation. I was using a 11"DD, 6.5" elliptical concentric, and a 5"DD round coil, on a Fisher F75.

Was hoping somebody out there has had more success with this kind of testing and would be willing to share.

Thanks,
Ron in WV

 

[CoinHunter2]

Have you tried montes nail board test. Your 5" coil will be the one that well seperate best, in iron infested areas

 

[WV62]

I have heard of his nail board but never tried coils on one. I agree the 5" should be the best, but that 6.5" coil is pretty slim like 3.25" wide. That 5" has that hot bar running down the middle which is pretty much its unseen width.

Now since I done that testing I have a new NEL snake coil for the F75 and it is about 6.5 x 3.5 and it is a DD coil and I was hoping to find a way to test them. The depth on the 3 small coils are all about the same, so the best separation would be the one for me to hunt with.

Ron in WV

 

[D&P-OR]

Ron------How does your new Snake coil do in comparison to the 5 DD as to separation & depth?

I have heard of his nail board but never tried coils on one. I agree the 5" should be the best, but that 6.5" coil is pretty slim like 3.25" wide. That 5" has that hot bar running down the middle which is pretty much its unseen width.

Now since I done that testing I have a new NEL snake coil for the F75 and it is about 6.5 x 3.5 and it is a DD coil and I was hoping to find a way to test them. The depth on the 3 small coils are all about the same, so the best separation would be the one for me to hunt with.

Ron in WV

 

[WV62]

D&P,

I haven't hunted the snake coil much, but the time or 2 that I did have it out it done fine. The only depth testing I have done on it is air testing and it tested so close to the 5" and the 6.5" I couldn't tell much difference.

I am talking fractions of a inch, but if I had to line them up as the deepest, the 6.5" concentric, then the 5"DD, and the snake last. As for separation I was hoping this thread would give some ideas for testing. When some of this snow melts I may just have to put the snake on the stick and hunt it hard for few hunts and maybe I could get a feel for separation.

Ron in WV

 

[Tom Slick]

Just lay two pennies on the ground and keep pushing them closer together until you can no longer get two separate beeps while swinging over them. Measure the distance and then try another coil.

 

[Nauti]

Hi Ron,forget nailboard tests as they are completely useless and wont tell you a thing.If you want to test different coils for depth or seperation,the only accurate results you will get is if you test them on buried objects.Set up a test bed with targets at different distances from junk objects and at different heights in the soil.I can assure you that the results can be quite surprising to say the least and you will find that some set ups that you thought would perform well dont and some you thought would perform badly will do ok.
Nail board tests make me cringe to be quite honest.........they do not provide any useful information whatsoever and if you rely on such tests to help you decide what coil/detector works best in a certain situation,you will miss targets where it counts in the field.
When targets are buried they can give a totally different response to the results you get when they are tested on a nailboard so test them in a real world situation........under the soil.Also,one of the most important factors to remember is your machines ability to see a non ferous target next to a ferous one,it is a detectors ability to be able to reset to pick up a non ferous target after it has passed over a ferous target that counts in a high trash area which is more important than the coil type.
All the best,neil.

 

[WV62]

Just lay two pennies on the ground and keep pushing them closer together until you can no longer get two separate beeps while swinging over them. Measure the distance and then try another coil.

Okay I used 2 dimes, I think the material is more consistent than pennies, but other than a coin change I did this test. It did give me numbers that give me an idea of the best coil for target separation.

Okay a little drum roll,

These first 5 coils were all on the F75 detector.
1st place was the NEL snake, 7/8" on the center and down to 3/8" at the heel and toe.
2nd place 5"DD, 1" center and down to 3/8" at the toe.
3rd place surprise 5x10, 1 1/8" at center and was down to clean 7/8" heel and toe.
4th place 6.5" x 3.25 concentric, it had 1 1/8", no heel or toe number.
5th place NEL sharpshooter, it had 1 1/8", it went to 5th place because of larger foot print. Also no heel or toe number.

Then I put my 3.75" coil on my Fisher 1270, come in dead last at 1 3/8".

Ron in WV

 

[MarkCZ]

When I had my Omega and got the 5" round DD coil and the one thing that it seemed to have trouble with was coins that were "tilted" in the ground, I don't mean on edge, just titled, it would just pass them over. I never found no way to do an accurately test but even in simple air test it failed.
Probably the bad thing about that combo I had is I didn't have any other small coil to compare it with, so its possible that this could be a problem with any smaller coil on any detector???
I didn't keep that 5" coil after that, of course within a year or so I sold the Omega replaced it with a F70 to which I'm still leaning.

Mark

 

[slingshot]

Hi Ron,forget nailboard tests as they are completely useless and wont tell you a thing.If you want to test different coils for depth or seperation,the only accurate results you will get is if you test them on buried objects.Set up a test bed with targets at different distances from junk objects and at different heights in the soil.I can assure you that the results can be quite surprising to say the least and you will find that some set ups that you thought would perform well dont and some you thought would perform badly will do ok.
Nail board tests make me cringe to be quite honest.........they do not provide any useful information whatsoever and if you rely on such tests to help you decide what coil/detector works best in a certain situation,you will miss targets where it counts in the field.
When targets are buried they can give a totally different response to the results you get when they are tested on a nailboard so test them in a real world situation........under the soil.Also,one of the most important factors to remember is your machines ability to see a non ferous target next to a ferous one,it is a detectors ability to be able to reset to pick up a non ferous target after it has passed over a ferous target that counts in a high trash area which is more important than the coil type.
All the best,neil.

I believe you're probably right- I found dissimilar conductivity targets adjacent to each other and got separate tone and visual ids with my Ace 250 and it completely flunked the nail board test.

 

[supertraq]

Use a a block of foam with a iron nail above and left of the coin,1" above 1" to the side and put a hole in the block 1-2" below and silicone both in place.
See how many pass this closer to real world senerio.

 

[Nauti]

Hi slingshot,i found the same thing while testing different detectors.First I did a seperation test like those suggested above and then tested the detectors in a real world situation with a small coin buried in trash infested soil.The results were quite a shock........nearly all the detectors that did well in a so called nail board scenario failed to get a signal on the coin when it was buried in a real world test and the detector that did the best was one that did'nt perform that well on the "nailboard" test.
Another test that people do that is a complete waste of time is the discrim test on a big chunk of iron that sits on top of the ground.You see people demonstrating how their detector can discrim out the large chunk of iron but can still pick up a small coin.Most detectors can pass this test,but when the iron has been in the ground for a number of years it is a different story altogether.........it is not so easily discriminated in these circumstances.
Any test that is performed on targets that lie on top of the ground rarther than under it are pointless to say the least.....but heh,if such tests keep people amused......................

 

[supertraq]

Hi slingshot,i found the same thing while testing different detectors.First I did a seperation test like those suggested above and then tested the detectors in a real world situation with a small coin buried in trash infested soil.The results were quite a shock........nearly all the detectors that did well in a so called nail board scenario failed to get a signal on the coin when it was buried in a real world test and the detector that did the best was one that did'nt perform that well on the "nailboard" test.
Another test that people do that is a complete waste of time is the discrim test on a big chunk of iron that sits on top of the ground.You see people demonstrating how their detector can discrim out the large chunk of iron but can still pick up a small coin.Most detectors can pass this test,but when the iron has been in the ground for a number of years it is a different story altogether.........it is not so easily discriminated in these circumstances.
Any test that is performed on targets that lie on top of the ground rarther than under it are pointless to say the least.....but heh,if such tests keep people amused......................

100% agreement,coins and iiron junk are not laying on the top of the ground here in n.w Florida south Alabama and when you test with the coin at a different plane,I.E lower than the iron all of sudden the machines that kill it on a flat nail and coin test fail miserably.

 

[Nauti]

That is an important point that you bring up supertraq........targets in a different plane to junk targets.Why bother testing targets at the same level,ie on the top of the ground,when in reality targets are very rarely like this when they are buried.
Good point.