Some might find the system by James H. Rogers, developed in the era of World-War...

Some might find the system by James H. Rogers, developed in the era of World-War-One of interest. The late T.E.Bearden claimed that Rogers system was rediscovered and 'lost' at least seven times from then until our times.

"James H. ROGERS Underground & Underwater Radio

( Static-free Reception & Transmission Underwater & Underground )"

http://www.rexresearch.com/rogers/1rogers.htm