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VK6BE > CW 20.07.05 00:40l 28 Lines 1369 Bytes #999 (0) @ WW
BID : 6B0248VK6BE
Read: GUEST
Subj: Re: Fullerphone?
Path: DB0FHN<DB0FOR<DB0SIF<DB0FSG<DB0RGB<OK0PPL<DB0RES<DK0WUE<SP7MGD<VK7AX<
VK6HGR<VK6BBS<VK6BBR<VK6ZRT<VK6JY
Sent: 050719/0307Z @:VK6JY.#ALY.#WA.AUS.OC #:64085 [Albany] wFBB7 $:6B0248VK6B
From: VK6BE@VK6JY.#ALY.#WA.AUS.OC
To : CW@WW
A Fullerphone was a telegraph instrument used in the Australian and
possibly some other armies during the war. It was morse code only. It was
considered to be secure from enemy detection unlike some other telegraphic
instruments which could radiate from the communicating lines.
A buzzer was keyed and the resulting signal was fed to a synchronised
second buzzer which turned the signal into pulsating DC, an inaudible
signal on most receiving equipment. The DC signal went out over the lines.
There was no radiation from the lines and so it could not be detected (an
AC signal at audio frquency would radiate and could be detected by simple
receiving equipment, a DC signal could not.) In order to receive the
signal at the other end it had to be fed into a buzzer which would
resynchronise it and feed it into headphones as a reconstituted AC signal,
and therefor audible.. The unit consisted of a small black box with a
morse key integrated, and a double buzzer unit which handled the signals
both ways. The buzzers had to be carefully tuned to get the frequencies
right - from memory at about 500 herz.Very reliable unit and widely used
in the WW2 by the Australian Army.
Bob VK6BE.
>
> Please excuse my ignorance, but what is a Fullerphone? VK6BE mentioned this in one of his
submissions.
> (&) Andrew J. Bowlby
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