Why does my PI threshold?

[Anonymous]

Why does my PI threshold increase when I lower the coil down towards the wet saltwater beach? Yes, it will retune itself in a few moments. It does make it height sensitive however. Slightly lifting the coil will make the threshold vary. Annoying to say the least. Is there any way to adjust it (similiar to ground balance) so it is stable when raising or lowering the coil?? Thanks.

 

[Anonymous]

Hi Porter,
No PI ground balances to wet sand. At the sensitivity required to detect thin rings and some chains, there will always be some signal pick-up from salt wet sand, such that raising and lowering the coil will give a change in signal. You don't say which PI that you have, but some have an adjustable SAT (retune speed) control which helps the detector to adjust better to changing beach conductivity, when turned to a faster setting. Always keep the coil as parallel to the sand as possible when sweeping. Additionally, turning the pulse delay control to a later setting, will reduce the beach signal, although at the expense of small object sensitivity.
Eric.

 

[Anonymous]

Thanks Eric. I have tried several different machines, SD2100, Barracuda, and your BeachScan with similiar results. It would seem there could be some way to reset/lock the SAT threshold level to the new background once it is initially tuned to the wet salt?? Or how about just a knob that does the same thing and let me manually adjust it to the wet salt conditions. (A poor mans PI ground balance)?