[ARC5] Info for VHF Transmitter

[Cliff Miller]

Mike - The transmitter is the gray that matches the R-508 I have..
Everything you say is consistent with what I've seen in the photographs -
auxiliary shelf for the crystals over a  bank of 5 relays and there is an
extra relay that must be the bank selector.  I'll have to study the design
to see what will be needed to put the radio on 2 meters.
I have a Type 12 manual that doesn't mention the T-21 but now I can use the
info for the T-11A.
Thanks - Cliff W4HGR



On Sun, Jul 2, 2017 at 9:14 PM, Mike Morrow <kk5f at earthlink.net> wrote:

> I have no documentation on the T-21, but I know some things about it.
>
> It is nothing more than a T-11A 116 to 132 MHz transmjtter with an
> auxiliary shelf inserted at the back that plugs into the T-11A five crystal
> sockets.  On this shelf are two banks of five crytal sockets and one relay
> that selects between banks.  Two wires run from this relay to power and to
> an existing front panel connsctor pin.  This shelf therefore doubles the
> T-11A five channels to the T-21 ten channels.
>
> It should be trivial to find the pin connection that must be grounded to
> switch crystal banks.  Every other part of the circuit will be identical to
> the T-11A.
>
> The A.R.C. Type 12 gear first appeared for military and commercial markets
> in 1947, and is unrelated to the AN/ARC-5 except for some borrowed but
> highly-modified receiver designs.  Some stayed in service on secondary
> aircraft for a long tjme, like the sets on T-34B trajning aircraft at NAS
> Corpus Christie in 1972.  The T-21 would have been sold to commercial
> markets in the mid-1950s through early 1960s.
>
> Good luck.
>
> Mike / KK5F
>
> -----Original Message-----
> From: Cliff Miller
> Sent: Jul 1, 2017 12:20 PM
>
> Just bought an A.R.C. VHF transmitter marked T-21.  There is no mention of
> "ARC-5" on the label.  It has four 5763 tubes so must be similar in design
> to the T-13A of the Type 12 radio set except it has 10 crystals instead of
> 5.
> Any info or assistance in identifying this radio would be appreciated.  I
> haven't found any manual or schematic or article on a transmitter with this
> designation.
> My application for this is to pair it with an R-508 I have running.  I
> have that cabled up to an old control box using information on the R-19
> from my Type 12 manual.  That works fine to monitor air traffic passing by,
> LOL.
> My theory is that both of these are 50s radios rather than WW2, that these
> may have been civilian service products.
> Another orphan I've adopted is a single receiver C-22A control box for
> which I've found no information, either.  It worked with the R-508 in a
> fashion, except the volume control worked backwards (counter-clockwise =
> louder).
> Thanks!
>
> --
> Cliff Miller W4HGR
> cliff52 at gmail.com
>



-- 
Cliff Miller
cliff52 at gmail.com
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