[ARC5] AN/ARC-5 vs. SCR-274-N

[Mike Morrow]

Henry wrote:

> The usual US ID bakelite (?) etiquette .. "BC-45X .. replaced by plates 
> with the following text::
> (on one unit , 1.5 - 3 (MC /MHz):
>
> EMPFÄNGER
> E-274-1
> GERAT Nr, ***

> (on other unit, 3-8 MC / MHz) unit reads
> E-274-2
> GERAT Nr. ***

I assume you mean "3-6" and not "3-8".

> SO they both APPEAR to be  BC-45X  SCR-274-N units and not R/2X-ARC-5 
> units.

That is an incorrect conclusion, as can be quickly determined by reference to http://en.wikipedia.org/wiki/ARC-5 .

There is NO SUCH ANIMAL as an SCR-274-N receiver that covers 1.5 to 3.0 MHz.  That
positively rules out the E-274-1 unit as having been SCR-274-N.

Is the second IF tube of either unit a 12SK7, or is it a 12SF7?  ONLY the AN/ARC-5
receivers had a 12SF7 anywhere in them.  The RAV, ARA, and SCR-274-N used a 12SK7 as
the second IF.

Only the RAV CBY-46104, ARA CBY/CCT-46104, and the R-25/ARC-5 covered 1.5 to 3.0 MHz,
and I doubt that the E-274-1 started out life as either a RAV or ARA.

The RAV CBY-46105, ARA CBY/CCT-46105, SCR-274-N BC-454-A or -B, and the R-26/ARC-5
covered 3.0 to 6.0 MHz.

It is a trivial effort of about 15 seconds duration to distinguish an AN/ARC-5 unit from an SCR-274-N unit.  Just look for that 12SF7!

Mike / KK5F