[GreenKeys] RADIO TELETYPEWRITER AN/GRC-46

[Scott Johnson]

Well, it is after all, A "G"RC-46, not a "V"RC-46, so it is implied that it
is not used in motion. I can't see where it was contemplated in the manuals,
either. Same goes for the GRC-142 and -122.

Scott W7SVJ

-----Original Message-----
From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Duncan M. Brown
Sent: Tuesday, August 03, 2010 8:05 PM
To: NNN7DXB at aol.com
Cc: greenkeys
Subject: Re: [GreenKeys] RADIO TELETYPEWRITER AN/GRC-46


Dave,

Yes, designers often have little field experience and so they come up with
impractical ideas.  I can't understand how anyone would think they could
operate a GRC-26D in a city, especially with trolly lines!!  (maybe they
just forgot to put the antenna down)

I never saw a GRC-46 operated mobile.  I agree, the TT-98 probably wouldn't
do well with the vibration, though the TT-76 might have been OK. Of course
the operator might have had a little trouble keeping his fingers on the
keyboard.  The only practical mobile operation would have been voice or CW,
and then only in the "field" away from any trees.  In Viet Nam, we rarely
used the radios in the GRC-46. The Kw-7 connected to a modem (TH-5/TG) and
went out on a dedicated phone line.  So we just ran a 115VAC extension cord
into the shelter to power the TTYs & KW-7.  This was 1967 with the 337th
Radio Research Co. supporting the 1st Infantry Div.

The early AN/GRC-46s had a big, two pin, connector in the front wall (behind
the TT-76) for the 28VDC in.  I guess a mating connector was wired into the
vehicle electric system. To switch to external generator, one would have to
remove the vehicle connector and screw on a cable from the generator.
  At some point (c1967?) there was a modification to add a second power
connector (next to the original one) for the external generator. A big
switch box was added to the right of the TT-76 to be able to switch between
vehicle power and external generator power.  

I was actually working in a GRC-46C today at the AWA Museum. Trying to get
it working, but found I am missing a cable.

Have fun,

Duncan ______________________________________________________________
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