[Seden]

That is true regarding white noise not being able to get phase information from it. The post I had in mind by Esteban was on the first page of Andreas LRL,post#24 dated July 4th 02:51 AM where he refers about a Tesla Coil drawing he did which as you pointed out is not shown in the thread at all. So he goes on to describe the Tesla coil and how to tune it,etc.

Here's a another idea that would solve the lack of phase information and that would be to use a swept carrier which would be very simple to implement with a single 74hc4046 by taking the carrier from the VCO amplifying it and send it to the transmit coil and the receive coils output to the input of the PLL.

But I tell you J-Player,I'm really interested how you can determine what mineral or metal you have by the phase differences by using Spectral Induced Polarization whereby you look at the phase difference between a couple sub-audio frequencies (typically .01hz and 1hz). What determines the phase difference is the size of the mineral/metal grains. The downside is as you probably know, the naturally occuring noise really takes off below 1hz.

Thank you for contributing your technical thoughts to this thread,greatly appreciate it and learn alot.

Randy