[Milsurplus] TG-5 Telegraph question and part needed

[Richard]

First a bit of history.  at the beginning of WWI telegraph along the 
front used standard telegraph equipment, probably 20 to 60 ma line 
current, over one line and ground return.  The Germans were reading all 
the telegraph and telephone traffic by ground conduction using two 
ground rods and the new vacuum tube amplifiers.  They had the whole 
front covered, with wires running back from the front.  Half way through 
someone dimly realized our traffic was being read, and the Fullerphone 
was invented by Captain Fuller.  It used very small currents, as low as 
microamperes, with filters to round off the rise and fall, which was 
undetectable by ground conduction.  Our TG-5 and TG-5A came later, using 
currents as low as 1 to 1.5 ma which is apparently good enough.  TM 
11-351 Technical Manual for Telegraph Sets TG-5 and TG-5A dated 
September 22, 1941 says, "Authorized for and used by various  units of 
the Infantry, Field Artillery, Coast Guard Corps, and Signal Corps."  
They were used with ground return, and also piggybacked on simplex 
telephone circuits.  FWIW

Richard, AA1P

On 5/15/20 10:10 PM, Jack Antonio wrote:
> First. Does anyone have a spare BZ-7-N interrupter
> out of a TG-5B? It appears that the one in my unit
> is utterly dead. Failing a spare, I may have to
> build up a little 1kc tone oscillator to take its
> place.
>
> Now for the question.
>
> I've been playing with my two TG-5s, and am wondering
> about their usage.
>
> What units were assigned these? My thinking is that since
> field phone wire had to be run to these units, why not just
> issue them an EE-8 field phone? The phone would not require
> a trained morse operator.
>
> Jack Antonio
> WA7DIA
>