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

[Dennis Monticelli]

Much thanks for all the useful info.  While the lack of a BFO is a
disappointment, I can still use the schematic that Michael provided to
hook them up and see if they play.

On Sun, Jul 6, 2008 at 6:43 AM, Mike Morrow <kk5f at earthlink.net> wrote:
> 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
>