[ARC5] BC-453 usage?

[Mike Morrow]

>I was looking at the ARC-5 manual this morning and it said the "NAVIGATION
>RECEIVERS" could be used with loop antennas. I assume the R-23 and R-24 were
>the navigation receivers.
>
>Was there an SCR-274 equivalent to the R-24? My SCR-274 manual does not show
>it.

Yes, the "navigation" receivers were the R-23 and R-24/ARC-5, and the R-25 through R-28/ARC-5 were "communications" receivers.

As Robert said, the SCR-274-N broadcast band receiver was the BC-946-B.  If you get a really early SCR-274-N manual, it won't show the BC-696-A 3 to 4 MHz transmitter either.  And no SCR-274-N manual that I've ever heard of mentions the VHF components like the BC-942-B receiver and BC-950-A transmitter.

The "command set" 0.19 to 0.55 MHz beacon band units were:

USN   XRAV or RAV       CBY-46102
USN   ARA               CBY-46129
USAAF SCR-274-N         BC-453-A or -B
USN   AN/ARC-5          R-23 or R-23A/ARC-5

The "command set" 0.52 to 1.50 MHz broadcast band units were:

USN   XRAV or RAV       CBY-46103
USN   ARA               CBY-46145
USAAF SCR-274-N         BC-946-B
USN   AN/ARC-5          R-24/ARC-5

The rare XRAV/RAV versions of these receivers had loop antenna connections and an associated switch.  These were eliminated in the ARA versions.  The SCR-274-N versions were electrically identical to the ARA versions, except that A models had high impedance audio output rather than the low impedance audio output of the ARA.  B models can be wired for either low or high impedance audio output.  The R-23, -23A, and -24/ARC-5 units differ in many respects from the equivalent receivers of earlier versions, including having a specially filtered audio output through the optional MX-19/ARC-5 audio adapter unit for the AN/ARN-9 Air-Track ILS system.  Oddly, RAV-type loop antenna connections reappear on AN/ARC-5 navigation receivers.

Mike / KK5F