Whites TDI Classroom

I recently got a T-Foot coil from Jimmy Sierra. It's a dual field, 18"x5.5" coil. I got it mainly for great coverage on the beach.
Haven't had a chance to try it at the beach, but I hit a park with some big open fields with it this week. This place has its share of modern trash (caps, tabs, etc.) as well as a fair amount of iron trash. I set up the TDI with gain=9, delay=10, GB on and set at 4, switch to high conductors only. The coil swings nicely and the TDI ran quite smooth with it. I pulled up some old coins, at least old for this area -- a Walking Liberty half dollar, a Roosie, a silver Canadian dime, and 2 wheaties (the Merc and 2nd Roosie came later in the day when I switched to my Etrac). Also pulled a handful of clad coins, and a bit of junk, but not much, mostly flattened screw caps. Only dug one nail and it was vertical in the hole. No tabs, foil, or crowncaps! Depth is decent, but I don't think it goes quite as deep as the stock dual field coil.
Can't wait to try this out at the beach!
HH
Mike

Interesting.

Looking forward to see your beach report/results with this coil.

ivanll

To get more depth just turn your GB control up to 10 after you flip the switch to high conductor.

I know at 10 I'll get better depth, but the nails and iron also give a low tone at this GB of 10. If there isn't too much iron junk I'll run at a GB of 9 or 10, then when I get a signal will turn the GB down to 4 or 5. If the signal goes away, it's iron ( it's changed to a high tone at the lower GB). If the signal stays as a low tone, I'll dig it.
I think with more practice using the TDI I will get better at hearing the difference between iron and a high conductor coin at the GB=10 setting (not just the tell tale double blip of a lengthwise nail). But now I think it's great that I can dig coins with this PI and ignore most iron and aluminum trash.
Mike