[ARC5] Strange LF Set?

[Mike Morrow]

> Reference ebay item 321065369521

It's easier for the reader to cite http://www.ebay.com/itm/321065369521
(unless he uses html or rich-text, which doesn't seem to create clickable
links when URLs are displayed the way plain text does).

> Now why would such a 190-550 KC set have the multiple antenna jacks and
> the ARR-1 power adapter?

There is nothing odd about that.  The R-23/ARC-5, R-23A/ARC-5, R-24/ARC-5,
and R-148/ARC-5 navigation receivers **all** have loop connections and switch.

The ARA navigation receivers CBY/CCT-46129 and CBY/CCT-46145 do not, nor do
the SCR-274-N BC-453-* and BC-946-B navigation receivers.

Before these command receivers, the 1940 RAV liaison receiver system used
CBY-46102 and CBY-46103 navigation receivers that had the loop connections
and switch.  These were resurrected, for God knows what reason, on the
AN/ARC-5 navigation receivers listed above.

The item shown in the auction is obviously just a common R-23 or R-23A, or a
rare R-148.

The power adapter MX-20/ARC-5, standard equipment on the R-24/ARC-5 for use
with the AN/ARR-1, was very commonly installed on other receivers.  On the
R-23* or other receiver, it would *not* have supplied a R-1/ARR-1.  But it
could have supplied a LM-* frequency meter, a O-4/ARC-5 crystal-controlled
frequency standard, or even a DU-* loop if for some bizarre reason someone
though that antiquity was necessary.

The actual power adapter shown in the auction is the CBY-62036 from the ARA
system.

> Looks pretty unhacked, except for the natural aluminum tube cover, and we
> have seen that bare AL parts did find their way into black wrinkle sets,
> even without field fiddlin'.

Not really in USN service, all of whose gear was black wrinkle.  That was only
likely in USAAF SCR-274-N installations.  The bare tube cover is definitely
**not** original to the set.  All AN/ARC-5 receiver tube covers have mounting
fixtures for storage of the small remote control box dial, and a base for
storage of the lock-tuned receiver tuning key ARC-9554 (not supplied with
navigation receivers, but the base is still there).  The presence of those
structures can easily be seen on the top of any proper AN/ARC-5 tube cover,
and they aren't on the auction example.

There are also some screws missing, and the top cover itself may be from an
SCR-274-N unit.  It looks pretty hacked to me.

> I don't suppose there is any reason someone could not have taken an adapter
> and plugged it into an LF set.

Why not?  It happened very frequently in real military use.  There is also
a less frequently seen audio adapter panel called the MX-19/ARC-5 that
interfaced between the R-23*/ARC-5 used as an ILS localizer receiver and
the short-lived AN/ARN-9 "Air-Track" ILS system.

FWIW, the complete set of AN/ARC-5 receiver adapters are:

C-24/ARC-5 local control adapter
MX-19/ARC-5 ILS (AN/ARN-9) adapter
MX-20/ARC-5 Homing (AN/ARR-1) or general purpose power adapter
MX-21/ARC-5 Standard (except for R-24) remote control adapter.

Mike / KK5F