22 Jun 2018

CIA 1960 report on earth current signalling

An amateur in Germany, DL3IKE, found this recently:

https://www.cia.gov/library/readingroom/docs/CIA-RDP78-03424A000400090001-9.pdf

1 comment:

Ken May said...

Looks like 136Khz should do well but my own earth rod tests at this freq never produced much of note, but I don't have the luxury of 100m spacing nor a well!

73 Ken G4APB