[GreenKeys] GRC-26

[Ken Kinderman]

In response to few queries as to just what the GRC-26 is, here is a brief
rundown...

The GRC-26 is a transportable shelter, about 7' x 7' x 14' on the bed of a
GMC M-211 two-and-half ton truck. It doesn't have to be on a truck. Dropped
onto the ground, it can be called an MRC-32.

Mine is the -A version. It uses:

- a BC-610H and BC-939 Tuner

- two R-388's two TG-7B's (modifed by B&W into something called a TT-55 but
still a TG-7B).

- A Model 14 Typing Reperf and the accompanying TD

- A control unit that routes the TTY lines inside the shelter

- A dual diversity frequency shift receive converter that works off the 2 IF
outputs of the R-388's

- A Frequency Shift exciter O-39/TRA-7, essentially a 90 pound VFO with F.S.
capability, that feeds the BC-610

- A couple of LS-3 speakers

- An A-11 aircraft clock in a cute little box

- A pair of EE-8 field phones ("Run a pair of wires from the interior of the
GRC-26A to the cab of the truck in order to communicate with the driver."
Talk about hands-free driving....)

- Lots of other accessories including "Broom, floor"

- Great big transmitting whip, and provision for three smaller receive whips

- Storage straps on the side of the shelter for poles for two big dipoles...
the preferred setup for dual diversity

The entire left side of the shelter is taken up with a monster storage
cabinet.

The earliest version used a pair of BC-342's (110 vac version of the
BC-312), modified for increased stability.

Later models, down to the -D version used later model TTY gear (RATT as the
manuals call it), along with R-390A's and a T-368.

The purpose of all versions was the same: basically tactical or mid level
TTY origination and relay, along with voice capability. Some guys who used
it in the 50's and 60's report the inclusion of encrytion and code burst
gear. CW was an afterthought: J-47 key on a leg clamp. Because it used IF
detection for the TTY signals, it was also possible to voice modulate the
BC-610H while transmitting and receiving frequency shift TTY. By using
separate receive and transmit frequencies, full duplex operation is
possible, using voice and TTY simultaneously. Talk while typing, so to
speak.

Curiously, you throw it from R to T with a big clunky switch on the C-808
control unit... the PTT line from the BC-614 speech amp connected to the
BC-610H is left unconnected. So using either the T-50 or the T-17 for voice
required flipping the switch and still holding down the mic. button.

As Jack knows, I have been taking my time over the years first with cosmetic
refurbishing of the shelter itself, then with the radio gear. I bought it
from Fair Radio years ago and it was a mess externally. But inside, it was
like a time capsule from 1952, including spare ribbons that still type.
Nonetheless, the TTY gear hadn't been touched in almost 60 years, so as
great as those machines are when they are running well, they needed major
overhaul, which I am just getting around to now.

Anyway, that's the short version of the story. Then there's the truck... ten
tires and two heavy duty batteries among other babysitting chores...

73,

Ken
W2EWL