Karl Harrar talks about using Ground Penetrating Radar (GPR) to locate privies, trash pit, and Civil War soldier winter huts. He also discusses the new GPR units he builds that are affordable and effective. Karl is an avid bottle/pottery digger and manufacture ground penetrating radar systems in Aiken SC, and is also an Electrical Engineer at Savannah River National Laboratory.
Check out Bill Baab's article on Karl, "An Affordable Look Under Ground" in American Digger Magazine's March-April 2019 issue beginning on page 52.

Here is the link to Karl's Facebook page: https://www.facebook.com/karlharrar
Here is a link to his Easy Radar USA page: https://www.facebook.com/easyradarusa/