[ARC5] R-11A and R-511 info

[Mike Morrow]

Dennis wrote:

>I picked up an A.R.C. R-11A and an A.R.C. R-511 receiver at the swap
>today.  I presume these are a part of the Type 12 series.

Correct.  The USAF seems to have purchased these A.R.C. units with
either an A.R.C. commercial model number (R-11A) or a military JAN
nomenclature (R-511/ARC).  But even the ones with the commercial model
number will usually have a small "U.S." and/or a military contract
number on the name plate.  I doubt there was little civil aviation use
of the A.R.C. Type 12 gear...it had to be very expensive for such a
dated design.

>Both radios have 85 KHz IF's so they must be VLF units.

There was never a version for the VLF band (3 to 30 kHz).
These sets cover 190 to 550 kHz, so they cover the top part
of the LF (30 to 300 kHz) and the bottom part of the MF
(300 to 3000 kHz) band. 

>Does anyone know what is different between these two models

There is no difference between the R-11A and the R-511/ARC except
nameplate.

>and also how different they are from a BC-453?  I noticed that
>they have mostly loctals for tubes.

Aside from the obvious lack of tuning dial and the fact that
all connection are made from the front, the lack of a BFO is
the major difference.

Thus, there's no A1 Morse reception with these.  When I fired
up my first BC-453-B 45 years ago, the merchant marine MF Morse
band from 410 to 512 kHz was an extremely interesting band that
could be received with these LF/MF units.  I really enjoyed
listening to the distress and calling frequency (500 kHz)
at night, and in the 1960s these old command set beacon band
units served surprisingly well.  Most commercial-design aviation
beacon band units covered only 200 to 400 kHz and had no BFO.
Sadly, the BFO-less R-11A and R-511/ARC would also be unsuitable.
Even their use in "Q5-er" service would have been hurt by lack of
BFO unless A3 AM only was OK.  Of course, merchant marine Morse
operation finally died out a decade ago, so the few aviation
NDBs still operating are about all one hears on these sets today.
The weather and airport info that was once broadcast in voice
on some NDB frequencies ceased long ago too.

>Can you still find control boxes for them and are schematics
>available?

Controls, connectors, and mounts are much rarer than the receivers.
Ebay is without doubt the most likely source, but the search will
be long.  Fair Radio has some connectors.

I can send a schematic once my manual collection is available.
But I'm in the process of a move and all my sources are boxed
up and will be for some time.  But information is pretty easy
to find, the best being an A.R.C. Type 12 manual such as shows
up on ebay fairly often.  I believe Fair Radio also sells a
repro manual, but if Robert Downs has such in his inventory
his will be far higher in quality.

Mike / KK5F