[ARC5] CBY-46104 Receiver - Command Set Navigators

[Mike Morrow]

>I may have been melding the R-24 and R-25 in my mind...

Hi Dave,

I too wrote a couple of things I didn't intend with:

>Like the CBY-46145/ARA and the BC-946-B, the R-24 broadcast
>band receiver was apparently mainly intended to serve with
>the AN/ARR-1 (or ZB or ZBX) 246 mc homing adapter, since all
>R-24 (and ARA and BC-946-B) units came with the MX-20/ARC-5
>(or CBY-62036 or FT-310-A) power adapter for the R-1/ARR-1.

That implies that the ZBX fed into a BCB receiver, but the ZBX was the pre-JAN USN name for the R-4/ARR-2 stand-alone homing receiver.  One could also interpret the remainder of the sentence as saying that all ARA units came with a CBY-62036 power adapter, when only the CBY-46145 did.

Corrected text:

>Like the CBY-46145/ARA and the BC-946-B, the R-24 broadcast
>band receiver was apparently mainly intended to serve with
>the AN/ARR-1 (or ZB) 246 mc homing adapter, since all R-24
>(and CBY-46145/ARA and BC-946-B) units came with the MX-20/ARC-5
>(or CBY-62036 or FT-310-A) power adapter for the R-1/ARR-1
>(or ZB).

I've just about concluded that a complete SCR-274-N set ought to include the BC-946-B and the R-1/ARR-1 (with Signal Corps markings).  I need to locate plugs for the connector (PL-74?) for the power adapter and the large connector on the R-1, plus a MC-415 BCB control box dial.

I would enjoy hearing other list members' speculation why, on so many Signal Corps R-1/ARR-1 units, the antenna input coil assembly has had the mica insulation broken, and most of it removed.  In addition, the 2 uuF capacitor C132 across part of the coil is always found removed.  The resulting configuration should still work, but with less effective capacitance (C132 gone, structural mica gone) across the input coil.  I speculate that this was done purposefully because the capacitance of the coax leading to the antenna made it necessary to eliminate as much capacitance as possible in the input circuit.  But that's just a guess.  If it was intended to be a "demil" mod, I can think of much easier and more effective ways than this.

I have never seen this "mod" (if that's what it is) on USN ZB-* units.  I do have one well-used USN R-1/ARR-1 that has had C132 removed, but without any attempt to remove insulating mica.

Walt Hutchens in ER speculated that rough use on aircraft carriers caused the insulation cracking (but only at the input coil??).  But no USN ZB or USN R-1 that I've seen shows this, while all Signal Corps R-1 units that I've ever seen do, even those in new unused condition.

Has anyone come across any indication that the USAAF ever acquired the AN/ARR-2?

Mike / KK5F