[GreenKeys] RADIO TELETYPEWRITER AN/GRC-46

[Duncan M. Brown]

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