I wouldn't go as far as saying air tests are total crap, but, they're
NOT a fullproof, spot-on grade of what a detector is capable of. An air test is basically a good guide...an approximation of what a detector
could do. **Realize this - Once a target (coin, jewelry, relic, etc.) has been in the ground for a long period of time it develops a 'halo' around the object. This halo effect makes it possible for the detector to 'see' the target MUCH deeper than it would in an air test**
Remember too that MANY other variables affect a detectors depth - or lack thereof. The ground being dry (especially during the Summer months) can drastically affect depth. The size of the coil, the speed of your coil swing, the size of the targets your chasing, the frequency of the detector you're using, etc., etc., etc. Sooooooo...
It's almost impossible to figure out why you're not getting the depth you claim you're missing out on. Too many variables. Oh yeah, when in doubt, MEASURE YOUR DUG HOLES
Too often detectorists will approximate and say a target was found at 2", 4", etc., when in reality it might have been 8" or 9". So, measure, measure, measure when you feel something's wrong.
Make yourself a test garden and do some testing. Even better, film the results & post them. Then, if there IS indeed something wrong, we might be able to get a better handle on the situation.
**TIPS**
S-L-O-W D-O-W-N...then slow down even more
Overlap your coil sweeps by at least 50%
Don't set you sensitivity too high or too low - find the sweet spot
Don't use too much discrimination - this cuts down the depth of ALL detectors a
LOT
Try scrubbing the coil through the grass or on the ground - GENTLY
Listen for the faint, barely there, whisper signals. Most surface hits are junk. The deeper whipers are where the goodies are
Good luck!
