Ground balancing 12x10" SEF (Butterfly) coil

[homebre]

I have been using the 12x10" SEF (Butterfly) coil on my V lately and have been finding some good stuff. However, I am having trouble ground balancing it. As I lower the coil to the ground , the tone seems to drop out, then suddenly gets louder. I have had no trouble ground balancing with the standard 8x9 coil, but this one gives me trouble. I thought it was a delay caused by the wireless earphones, so I used standard earphones, and it still did this. However, it doesn't seem to be much of a problem, as I am finding some nice things. Any advice?
thx,
Andy from Hillsborough

 

[Mike Hillis]

Hi Andy,
You'll probably have to stop the coil about 2" to 2-1/2" above the ground if you have any minerals due to the coil field.

HH
Mike

 

[homebre]

Thanks--but I am not sure what you mean. Do you mean get a constant tone and bring the coil down just to just 2 inches above soil and assume it is balanced if there is no tone change until then?

Andy from Hillsboorugh

 

[Mike Hillis]

Yes, just bob the coil just above where the tone drops out. Getting to close the the bottom of the large DD coil can cause wierd things to happen cause the fields is a bit screwy in that last two inches or so.

HH
Mike

 

[BarberBill]

My limited experience with larger coils tends towards higher difficulty when ground balancing, probably due to the larger acceptance field.
BB

 

[Cliff KS]

So how about actual detecting?? -- keep coil a couple of inches above ground or OK to get it almost touching ground?

I have trouble balancing the 12x10 on my Tejon and it seems to be very chatty, but I have still found things with it. The soil is fairly mild here. Any suggestions? I'm thinking that I am probably not getting it ground balanced correctly or else it would run smoother/quieter ?