[ARC5] BC-1206-CM...and other WWII Beacon Band Units

[Clare Owens]

Hi Mike,

I just looked at my BC-1206-CM2 and it has a phenolic terminal strip
labelled GND, 28V, OUTPUT and ANT.  No Jones plug.  Maybe there were two
versions??

Clare




On Thu, Nov 8, 2012 at 11:23 AM, Mike Morrow <kk5f at earthlink.net> wrote:

> > also a 512 model that is for 12volts but this requires a separate B+
> supply about
> > 150v will do ..different tubes..may be made by Detrola but no maker on
> mine..
>
> Definitely not Detrola.  Detrola made the Model 438, BC-1206-A, and
> BC-1206-B,
> which are all basically the same.
>
> The 12-vdc filament model is the Setchell-Carlson Model 512.   In military
> service,
> The Model 512 has the JAN nomenclature of R-76/ARR-13, and it was used
> with the
> RCA AVT-112 HF transmitter and AVR-20-A1 HF receiver set in 12-vdc light
> observation
> aircraft.  These three units used one AVA-126 vibrator supply for HV,
> which was
> 250 vdc.
>
> RCA made an AVR-15 beacon band receiver that is the same size as the
> AVR-20-A1.
> The AVR-15 is considerably larger than the S-C Model 512, and also lacks
> the RF stage
> found in the Model 512 (AN/ARR-13).  I suspect that led to the use of the
> AN/ARR-13
> rather than the AVR-15 in these applications.
>
> > ...the 512 has a switch for a single beacon frequency or the normal 200
> to 400khz.
>
> No.  That switch selects three pre-adjusted capacitors to place the
> receiver on
> 278 kHz, which was the most common **tower** transmission frequency of the
> pre-
> and post-WWII era.
>
> There is another Setchell-Carlson beacon band unit...the
> dry-battery-powered
> S-C Model 591 (A and B batteries are required).  In military service it is
> the
> AN/CRR-1, and it was intended as the receiver companion to the SCR-578-*
> (BC-778-*)
> 500 kHz "Gibson Girl" hand-cranked emergency transmitter for USAAF aircraft
> operating over Arctic regions.  It operates from 190 to 420 kHz.
>
> So, common beacon band units of the WWII era in US military service were:
>
> Detrola Model 438
> Detrola Model 438 (BC-1206-A)
> Detrola Model 438 (BC-1206-B)
> Setchell-Carlson Model 512 (R-76/ARR-13)
> Setchell-Carlson Model 524
> Setchell-Carlson Model 524 (BC-1206-C, two major mechanical variants)
> Setchell-Carlson Model 524 (BC-1206-CM)
> Setchell-Carlson Model 524 (BC-1206-CM2)
> Setchell-Carlson Model 591 (AN/CRR-1)
> Ranger Model 111-C (BC-1206-D)
> RCA AVR-15
>
> IIRC, there are some tube-line up variations between the BC-1206-A and -B
> models,
> and the BC-1206-C, -CM, and CM2 models.
>
> IIRC, the main difference between the BC-1206-CM2 and earlier
> Setchell-Carlson
> beacon band Model 524 receivers is that a square four-pin Jones plug was
> used
> at the rear for the power connections.  I don't have a schematic for mine,
> but
> it is child's play with an ohm-meter to figure out the +28 vdc, common, and
> (maybe) AF output connections on ANY of these beacon band units.
>
> Mike / KK5F
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