Coil help:

[clyde123]

Hi all,
New to detecting and first time posting on this forum. I have been reading it for a good while and it's been very helpfull. I live in northern Utah and the phase numbers I get on the 705 go between 12 and 28 most of the time. I have the stock 9" MF CC Coil. My question is how much gain might I expect by going to the 10.5" MF DD Coil.

 

[Digger]

Welcome to the forum. With the information you provided, it appears your soil is what I would determine to be mid-moderately mineralized. As such, you would likely benefit from using one of the DD coil designs, compared to the stock 9-inch concentric. If you are primarily a coin hunter, you could expect to do well with the 10.5 DD at 7.5 kHz. However, if you were more inclined to hunt for jewelry, you might consider the 18.75 kHz version of the 10.5 - inch DD. I'm not sure what you are asking about how much gain you might expect. But I would expect your ground phase numbers to be 10+ digits higher, using the DD coils. And I would also expect you could run the DD coil a couple clicks higher in Sensitivity, with no loss of stability and very little (if any) increase in "chatter". Larger footprint + more Sensitivity = greater depth of detection. HH Randy

 

[mapper65]

It's pretty common for me to get a 28 or slightly less when I ground balance. I have both 10.5" coils. I've done really well with both coils but as I've said here in the past the HF coil is more forgiving. You can use a little faster sweep speed and the depth is nearly as good at the MF coil. The MF coil is not as good with nickels but you will find them. If I really had to pick one of those two coils I would probably go with the HF coil just because the 705's detection and recovery speed seems to be a little faster than with the HF coil. If you are deciding on one of those two coils don't beat yourself up too much about making the wrong choice. With the ground balance numbers you are getting, either coil will do well for you. You just have to sweep a little slower when using the MF coil.

 

[clyde123]

Thanks Digger for the help. I will be hunting coins jewelry and relics, just injoy detecting. Think I will try the 10.5 MF. Thanks agin and will post my findings in the future.

 

[clyde123]

It's pretty common for me to get a 28 or slightly less when I ground balance. I have both 10.5" coils. I've done really well with both coils but as I've said here in the past the HF coil is more forgiving. You can use a little faster sweep speed and the depth is nearly as good at the MF coil. The MF coil is not as good with nickels but you will find them. If I really had to pick one of those two coils I would probably go with the HF coil just because the 705's detection and recovery speed seems to be a little faster than with the HF coil. If you are deciding on one of those two coils don't beat yourself up too much about making the wrong choice. With the ground balance numbers you are getting, either coil will do well for you. You just have to sweep a little slower when using the MF coil.

Thanks for the reply, think I'll start with the 10.5 MF. When I get it and have time to use it a while I'll post how it works out for me.