build your own GPR unit for $500

[hackaday.io]

[voidmapper.com]



Edited 1 time(s). Last edit at 08/25/2015 10:09AM by diggers.

Judging by the size of the antenna elements, it runs at 400-ish MHz, which is a bit low, suitable for finding large items 10+ inches across, and large voids. I understand that if you go much above 1000 MHz you run into the problem of the ground absorbing the signal (water-related). So the commercial units tend to run near to 1000 MHz to resolve smaller targets, 5 inches maybe.
The Geotech1 forum has some threads on GPR, I haven't looked to see what the latest ideas are there.