Digger_O'Dell
08-19-2015, 02:33 AM
Hello all!
Since I now got stuck working 84 plus hours a week for an indefinite term, I am thinking about purchasing a new DD coil for my X-Terra 705. I already have the stock 7.5 KHz concentric and the 18.75 KHz DD as part of thee package I bought. Being that Minelab has a very limited selection, and coils being pricey I was looking at the Coiltek 15" series. As I'm usually searching more open areas for coins, I was thinking the larger size would be a big advantage. But once again there is the question of which frequency to go with. I watched the videos doing the air depth tests, and all 3 frequencies were about the same within maybe 1/2 inch. Personally I have been leaning towards the 3KHz coil. So here's what I got out of the videos and literature:
The 3 KHz coil seems to be more reactive to higher conductive metals such as silver, which is what I am seeking most. But it is supposedly disadvantaged with metals such as iron or gold, and I would really hate to miss out on a gold find if possible. But, the advantage here also is supposed to be greater depth in the ground over the other 2, and better resolution around nails and such-or so I hear. It's also said it's not the best at small targets-whatever that may mean. My 7.5 KHz concentric has picked up a partial rusty staple at 6 inches-how small do I need to go? lol
The 7.5 KHz coil is supposed to be a good all around coil that will get both high and low conductive metals equally. So either gold or silver would be picked up pretty much the same and other than a DD configuration with the advantages there, it wouldn't be that much different from the concentric I already have.
The 18.75 KHz coil I couldn't justify as I already have the Minelab DD coil in this frequency, just a bit smaller. I like this for trashy areas where I can more easily pick between the garbage, and for highly mineralized areas such as on the black sand beaches near me. The only problem is it is not a waterproof coil, so have to be careful.
Overall, I really don't see any real advantage of one frequency over another in most cases, only at the far limits of detecting is where one seems to make any difference over another, depending on the target. So, my question is is anyone can shed more light on this topic of frequency choice, and if anyone has any experiences they can share comparing one to another. Thanks!
Here's the link to the coils: http://www.coiltekmanufacturing.com.au/products/coin-relic-and-treasure-coils/15-all-terrain-x-terra/
Since I now got stuck working 84 plus hours a week for an indefinite term, I am thinking about purchasing a new DD coil for my X-Terra 705. I already have the stock 7.5 KHz concentric and the 18.75 KHz DD as part of thee package I bought. Being that Minelab has a very limited selection, and coils being pricey I was looking at the Coiltek 15" series. As I'm usually searching more open areas for coins, I was thinking the larger size would be a big advantage. But once again there is the question of which frequency to go with. I watched the videos doing the air depth tests, and all 3 frequencies were about the same within maybe 1/2 inch. Personally I have been leaning towards the 3KHz coil. So here's what I got out of the videos and literature:
The 3 KHz coil seems to be more reactive to higher conductive metals such as silver, which is what I am seeking most. But it is supposedly disadvantaged with metals such as iron or gold, and I would really hate to miss out on a gold find if possible. But, the advantage here also is supposed to be greater depth in the ground over the other 2, and better resolution around nails and such-or so I hear. It's also said it's not the best at small targets-whatever that may mean. My 7.5 KHz concentric has picked up a partial rusty staple at 6 inches-how small do I need to go? lol
The 7.5 KHz coil is supposed to be a good all around coil that will get both high and low conductive metals equally. So either gold or silver would be picked up pretty much the same and other than a DD configuration with the advantages there, it wouldn't be that much different from the concentric I already have.
The 18.75 KHz coil I couldn't justify as I already have the Minelab DD coil in this frequency, just a bit smaller. I like this for trashy areas where I can more easily pick between the garbage, and for highly mineralized areas such as on the black sand beaches near me. The only problem is it is not a waterproof coil, so have to be careful.
Overall, I really don't see any real advantage of one frequency over another in most cases, only at the far limits of detecting is where one seems to make any difference over another, depending on the target. So, my question is is anyone can shed more light on this topic of frequency choice, and if anyone has any experiences they can share comparing one to another. Thanks!
Here's the link to the coils: http://www.coiltekmanufacturing.com.au/products/coin-relic-and-treasure-coils/15-all-terrain-x-terra/