[ARC5] BC-453 usage?

[Mike Morrow]

I wrote:

>Oddly, RAV-type loop antenna connections reappear on
>AN/ARC-5 navigation receivers.

Jay wrote:

>Wouldn't this be for the DU or DW loops?

LF/MF DFing using the manual DU-type of loop was current with RU-series receivers in the 1930s, but it was a very dated concept for US Navy aviation navigation by 1941 when the ZB-type VHF homing system became available.  Recognition of that obsolescence may be the reason that the ARA navigation receivers CBY-46129 and -46145 did not retain the loop connections of their predecessor receivers XRAV/RAV CBY-46102 and -46103.  Other receivers (MF/HF) in the XRAV/RAV system (which of course lack loop connections) are identical to their later ARA equivalents.  The 1.5 to 3.0, 3.0 to 6.0, and 6.0 to 9.1 MHz ARA receivers even retain the *same* USN component designations (CBY-46104, -46105, and -46106) that were used in the RAV system.

So, when the USN and A.R.C. advanced the ARA design into the AN/ARC-5, one wonders about the justification for resurrecting the old RAV loop connections for the 1943 AN/ARC-5 system.  I suspect it was a decision to build as much versatility as was easily possible into the R-23 and R-24, even if it was unlikely to ever be utilized.  Hence, the R-23 and -24 receivers could be connected to a DU LF/MF loop, an AN/ARR-1 (ZB-type) VHF homing adapter, or an AN/ARN-9 Air-Track instrument landing system.  It isn't likely that these options were utilized to any extent, since the LF/MF DF function was largely superceded by the ZB-type VHF homing system, the ZB-type homing combo of the R-24 and AN/ARR-1 was replaced by the R-4/ARR-2, and the AN/ARN-9 ILS was stillborn, replaced by the superior USAAF SCS-51 ILS.

There isn't much (or any, AFAIK) documentation of military use of an R-23 or R-24 with a DF loop of any type.  It is likely that USN aircraft in the PTO, navigating between carriers and islands, seldom had an R-23 or R-24 installed in their three-receiver AN/ARC-5 racks.  Instead, an R-4/ARR-2 VHF homing receiver would have been far more valuable in that rack.  Stateside, for flight in civil airspace, the R-4/ARR-2 could be quickly replaced by an R-23 for navigation between aural directional A-N beacons. 

Mike / KK5F