AT air tests not impressive

[nor10]

I have to agree and wander about my own At Pro. I did air tests with my stock 8.5 x 11 coil as well as my 5 x 8. My air tests are also less than impressive. I can get max depth of 6 inches on a silver dime with the smaller coil. The larger stock coil, i am lucky if i get 7 inches. Now i have found some great stuff with mine nonetheless. Just found 2 silver rosies and a silver washington quarter last week in the same hunt, so it is producing but all my good finds so far have been very shallow. Also, i had an At Pro right after the falsing and cam lock fix. I sold it to my brother to try other machines. Needless to say i came back to the At Pro. Anyway, that first one would air test at 11 plus inches on a dime and i could get close to 14 on gold. That is no exaggeration.
I wander why this one is so different. Also, i have noticed at times my battery meter and sensitivity bar flashes erractictly. Is this EMI or a hardware problem?

 

[pax]

so for gold and silver rings would you turn up the GB 10-20?

 

[nor10]

I generally ground balance my machine before every hunt. It typically GB's around 84. So thats what i perform my air test at. Now last week after reading something on Dankowski's forum about running it at a GB balue of 72. I did that last week when i found the silvers in one hunt. Coincidence? I dont know. My air test performed at that value doesnt produce different results though.