Double "D" coils for White's 6.5 Khz machines?

[kgxlt61]

Year old post, but Ill add my 2 cents...
The big foot coil is a figure 8 transmit coil on the inside "for balance" the receive coil is on the outside of that in the same plane. Quiet coil to cover ground, but not deep.

 

[Critterhunter]

Concerning DD potential options for the low freq Whites, search the modifications forum as there is a thread on a dongle that adapts Fisher and other brand coils to them (based on which dongle you get). So far as I know nobody has chimed in with a field report on this to see if say a 12x10 SEF for the Fishers works well on it. I'm highly interested, as I suspect this dongle has components in it to "mate" other brand coils to the Whites, unlike some in the past that were just coil cable pin configurations, where what little I read on those was not too impressive performance wise.

If that dongle will mate a SEF 12x10 for a Fisher to the old low freq Whites, I might have to pick up another QXT Pro (planned to anyway some day) to see if it will push depths further in my mineralized soil, help with stability, and also improve left/right separation. The SEF 12x10 has done wonders for my machine in all respects of those things. A low freq Whites might do some serious damage in my soil going after deep silver and copper coins if the coil mates well.