[ARC5] Re: Needful Things

[Mike Morrow]

Hi Michael,

You wrote:

>The Navy R-1/ARR-1s were likely used for replacement purposes for
>those aircraft still flying with RUs and ARAs still in service.  I
>believe the ARR-2 was primarily used with ARC-5 installations since
>the R-24* was used like the R-23* as a navigation receiver.   On the
>other talon, the R-24s did come with the power adapter used for the
>ARR-1 so there may also have been a source of supply problem.

I think that late-WWII ARA/ATA units were also made primarily for replacement purposes, since there would be little logic to installing all new ARA/ATA sets after the AN/ARC-5 was widely available.

With respect to the R-24/ARC-5, that unit could serve several functions:

1.  Host receiver for the ZB-series or AN/ARR-1 homing adapters, when equiped
    with the MX-20/ARC-5 power adapter.  The MX-20 was supplied with all R-24s.
    I believe this was the ONLY real intended function of command set BCB units.
2.  MF localizer receiver for the Air-Track ILS (ZA, ZAX, AN/ARN-9), when equiped
    with the MX-19/ARC-5 audio adapter.  Aside from the fact that this early ILS
    was quickly replaced by the USAAF's incompatible but much superior SCS-51 ILS,
    I doubt that the R-24 would have actually have served this role.  ZA MF
    localizer frequencies were in the beacon band, not the BCB.   
3.  BCB DF receiver using the DU-* series loop, powered perhaps through the MX-20
    adapter.  I doubt that DU-* loops were in much actual use even prior to WWII,
    after the ZB/YG homing system was developed.  There were no BCB directional
    Adcoock beacons, so use of the R-24 alone in a navigator role is very doubtful.
4.  Use as a communications receiver to accompany a T-15, -16, -17/ARC-5
    BCB transmitter?  Not likely, but wouldn't we all like to find out what intended
    use those BCB transmitters had?      
4.  Broadcast band entertainment radio for aircrews...fat chance! :-)

I think that the only real intended navigational function of the R-24/ARC-5 was item 1 above, which was replaced by the AN/ARR-2.  My CBY-46145, BC-946-B, and R-24/ARC-5 BCB units are all NOS, as were all such units that I've ever seen before hams got a hold of them.

>The BC-946-* came into being to use with the ARR-1.  To the best of my
>knowledge the Army never used the ARR-2.

I've never come across any indication of USAAF use of the AN/ARR-2 either, and precious little other than the surviving (but almost always unused) BC-946-B and Signal Corp contract R-1/ARR-1 units to indicate USAAF interest in the system.

73,
Mike / KK5F