rob
Member
I am not sure whether I should post here or on the Teknetics forum but after chatting with the Godfather himself here on the Fisher forum, he recommended I post my results - so here goes:
My two detectors I swapped the coils for my test are:
Fisher F75 with the stock 11" DD, 61/2"X4" elliptical and the 5"DD coils.
Teknetics 4000 with the 11"DD and the stock 8" round.
I started out placing the 5" DD Fisher coil on my Tek 4000 and noticed that you can crank it all the way 100% on the sensitivity and she ran smooth with an absolute silent search. With the small Fisher coil, she had no problem getting my test garden dime at 6" but could only get my 9" dime in all metal with the coil on the ground and again, the sensitivity at 100%. As for the weight, talk about light? I have to say this setup has the Tesoro umax beat by a few ounces. I had the exact same results with the Fisher 61/2"elliptical coil with no noise and same depth and was able to run the sensitivity at 100%!
Probably the most interesting part of my coil swapping test was running my F75 with the stock 8" round Tek coil. Running this coil helped really quiet the machine down to where I could run it at 95% sensitivity with no noise. At 96%, it started to chatter though. Running the stock 11" DD Fisher coil has always given me EMI right at 78% here at my home. Here is the cool part; the F75 with the 8" Tek coil picked my 9" dime up in my test area with no problem.
As for the VDI numbers, with opposite coils on different detectors, they gave the exact numerical value 'till about 70. Depending on how far away the coin was from the coil, they would be off about 1 digit towards the right side of the numerical scale.
I have heard a few guys say that swapping coils may look good on the bench with an air test but in the real ground world, depth will be greatly decreased. Not so here... Anyway, please don't jump on me for my swapping coils test as I have heard from the experts not to do it. I will have to say the final test will be out in the field but so far like what I experienced.
Rob
My two detectors I swapped the coils for my test are:
Fisher F75 with the stock 11" DD, 61/2"X4" elliptical and the 5"DD coils.
Teknetics 4000 with the 11"DD and the stock 8" round.
I started out placing the 5" DD Fisher coil on my Tek 4000 and noticed that you can crank it all the way 100% on the sensitivity and she ran smooth with an absolute silent search. With the small Fisher coil, she had no problem getting my test garden dime at 6" but could only get my 9" dime in all metal with the coil on the ground and again, the sensitivity at 100%. As for the weight, talk about light? I have to say this setup has the Tesoro umax beat by a few ounces. I had the exact same results with the Fisher 61/2"elliptical coil with no noise and same depth and was able to run the sensitivity at 100%!
Probably the most interesting part of my coil swapping test was running my F75 with the stock 8" round Tek coil. Running this coil helped really quiet the machine down to where I could run it at 95% sensitivity with no noise. At 96%, it started to chatter though. Running the stock 11" DD Fisher coil has always given me EMI right at 78% here at my home. Here is the cool part; the F75 with the 8" Tek coil picked my 9" dime up in my test area with no problem.
As for the VDI numbers, with opposite coils on different detectors, they gave the exact numerical value 'till about 70. Depending on how far away the coin was from the coil, they would be off about 1 digit towards the right side of the numerical scale.
I have heard a few guys say that swapping coils may look good on the bench with an air test but in the real ground world, depth will be greatly decreased. Not so here... Anyway, please don't jump on me for my swapping coils test as I have heard from the experts not to do it. I will have to say the final test will be out in the field but so far like what I experienced.
Rob