F70 coil surprise

Yeah, they aren't exactly the same but close enough the difference isn't much. Depth is probably clipped a bit. Works the other way around too. 7.7khz and 13khz aren't to far off from being harmonics of one another.

On a somewhat related front. I've noticed the greek/pro series detectors are now at 7.69kHz which is probably a closer match than 7.81kHz was. The land ranger pro all metal had more punch on 7.69kHz than the Omega on 7.81kHz. They share coils with G2/f19/GBP which is at 19.2kHz a 2.5X harmonic of 7.69kHz.

The new 7.69kHz do seem to have a little more smoothness about them.

My #1 coil to use on the F70.
Mine is the Fisher F75 coil.
Open it up and I have gotten as deep as 15" with actual screen I'd info, not just audio which is rare on most targets past 12".
Turn the sense down to 30 and the scanning field seems to shrink to a laser-like precision level for hunting in heavy trash if you don't happen to have a sniper coil handy and still get surprising depth.

Rim the front edge of that coil over a high tone pop top and as you pull back the numbers will drop so you can ID about 95% of these confidently.