TELECOM Digest OnLine - Sorted: Communications History

Communications History

Dave Marthouse (
Tue, 6 Dec 2005 23:33:02 -0500

I am a bit of a communications history buff. I've been doing a little
research about telecom in the days before transoceanic phone service
before cables and satellites. The only way to bridge the oceans was
hf radio. It's interesting to note that anyone with a shortwave radio
could listen to all the international point-to-point phone traffic. I
am going to assume that a form of independent sideband was used with a
maximum of two or four circuits going to a specific country. Ssb is
very easy to receive even with a standard shortwave radio of the day
as long as it had a bfo to demodulate and recover the signals. I
would like to know if any form of primitive encryption was used to
make the circuits a bit more secure. It must have been very easy to
literally monitor all the international traffic to and from a given
nation. Anyone who can shed light on this subject would be
appreciated to help scratch my historical itch.

Dave Marthouse

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