Mine's doing pretty well, post repairs...
It came-in dysfunctional, but Fisher fixed it up. Like a new machine now.
I believe (manual doesn't say, website doesn't say) that they run at around 6.5 khz. I know that BH coils work on mine because I used a BH coil on it for awhile.
The new F2s I'm seeing on "The Bay" aren't offering the extra coil and lower rod anymore. That might have been a Christmas package deal. I could be wrong abt that.
I'm liking mine as a coin-shooter, it's producing lots of clad and two wheaties in just 4 hunts.
Target seperation is above average and it works good at detecting targets next to a 'hot-rock' I use as a tester. This rock gives some of my machines fits.
I'm running sensitivity @ 2-3 on trashy sites and still able to hit targets 4+ inches deep. I can't see that it's really any better than most TID machines I've used at IDing nickels, but I'm no expert with the machine after so few hunts.
Seems like some aren't running like they should and some are. Fisher service, if you need it, has been very responsive. Felix is Top-Notch.
Skillet