Hi Jean-Louis and others,
On 2010 Feb 22, at 11:59, <[email protected]> wrote:
> Hi Rik
>
> In a french book called "Poste 85" describing the beginning of the
> electronics era during WW1 (telephone, radio, gonio, etc) , it is said that
> it was possible to listen to enemy telephone conversations by putting some
> rods in the ground and connecting them to a 3 triodes amplifier (the return
> audio ground current of the wire telephones were strong enough to allow
> conversations spying)
If this interests you, there's another book on the same subject: Listening In,
by Ernest H. Hinrichs, 148 pp., pub. White Mane Books, Shippensburg, PA, USA
(1996).
Hinrichs was a US national of German extraction, fluent in German, and served
with the US Army in WWI intercepting German front-line communications. His work
was with ground current communications, trying to pick up stray signals from
German field telephones. The book describes his WWI experiences and gives a
reasonable amount of technical detail of the equipment.
I seem to recall an assessment of it from the electronics point of view in the
Cave Radio and Electronics Group Journal, but I forget when. I think John F5VLF
wrote it; if you're interested, you could ask him.
There are over a dozen copies on AbeBooks, with prices starting at under EUR 4.
73,
Chris G4OKW
-----------------------
Dr Chris Trayner
School of Electronic & Electrical Engineering,
The University of Leeds,
Leeds LS2 9JT, United Kingdom
Tel: +44 113 34 32053
Fax: +44 113 34 32032
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