[ARC5] R-76/ARR-13

[Mike Morrow]

Ian wrote:

> This version of the BC-1206 has a 14A4 (triode, similar char. to 6J5) as the
> output tube. I have the schematic of the more common BC-1206-C which I
> think has the 28D8 as output tube.

WARNING:  Whatever you do, do NOT apply 28 vdc to it!

The R-76/ARR-13 is the JAN nomenclature of the Setchell-Carlson Model 512.
It is designed for 14 vdc aircraft systems, and that is how the filaments
are wired.  It also requires HV (250 vdc), and has a pull switch on the
front to select the common LF tower frequency of 278 kHz.  (In addition to
setting the LOCAL OSCILLATOR, this switch also alters the ANTENNA and RF
stage tuning as well, so the main dial does not need to be reset at all.)
It has a nominal AF output impedance of 600 ohms.

This receiver was intended to be the beacon/tower receiver for all those
RCA AVT-112/AVR-20/AVA-126 ferry and observation aircraft installations
that used 14 vdc input.  The designated power supply is the AVA-126 that
was part of the RCA HF set.  RCA had a beacon receiver AVR-15 that was
the same size as the AVR-20 (much larger than the R-76), and that also
has NO RF stage or 278 kHz preset!  Evidently the R-76 provided better
performance in a smaller package.

The common BC-1206 range receivers made by Setchell-Carlson are all
"Cxx" models (S-C Model 524) using 28 vdc for the filaments and plates.
None have a tower frequency preset.  There are at least two different
C-models, one CM-model, and one CM2-model.  I suspect the R-76 performed
a little better than the all-28 vdc BC-1206-C, but I'm sure that its
main advantage is that it could be used in 14 vdc aircraft while the
BC-1206 models could not.

The oddest Setchell-Carlson range receiver in military service was the
AN/CRR-1 (S-C Model 591).  This is a dry battery version.  The military
intended it for use with the SCR-578 (BC-778) "Gibson Girl" 500 kHz A2
emergency transmitter to give the distressed party on the ground a way
to receive transmissions from rescue aircraft or ships.  In particular,
the AN/CRR-1 was intended for aircraft with routes over the Arctic!

I'll send you a scan of the schematic of the R-76 a little later this
morning when I get my scanner fired up.  Anyone else need this?

Mike / KK5F