[ARC5] AN/ARC-5X Details and Remarks

[Mike Morrow]

Mark wrote:

> That what I was told, but when the owner sent photos it turned out to be 
> an R-148/ARC-5X, which does fit in the FT-220A.

The R-148/ARC-5X is the *only* AN/ARC-5 receiver built for 14-vdc operation.
It is equivalent to the improved R-23A/ARC-5, not the R-23/ARC-5.

It was designed for those few 14-vdc naval aircraft that were still around
after WWII.  It was *not* a part of a command receiver system, but only provided
beacon band reception that was essential for state-side aircraft operation.
Beacon band 28-vdc receivers R-23 and R-23A/ARC-5 in the USN, BC-453-B in the
USAF, and A.R.C. R-11A for both services were found in service in older
aircraft even into the 1970s.

The R-148 requires a 14-vdc dynamotor and 14-vdc single-receiver mounting rack.
Receiver mounting racks have a modulator-sidetone/receiver-output AF switching
relay for each receiver in the rack, so the MT-411/ARC-5X uses a single 14-vdc
relay K-1.  That is the only difference between it and the common 28-vdc
single receiver rack MT-7A/ARR-2.

The sidetone/receiver-output switching relay K-1 is only energized during
transmit, but AN/ARC-5X units have no associated 14-vdc transmitters.  Thus
it is unlikely that K-1 would ever need to be energized in a AN/ARC-5X
installation. 

For a remote controlled installation that does not require remote switching
of the antenna/loop inputs, the following support is required:

C-26/ARC-5 control box, or C-125/ARC-5 control panel, or C-744/ARC-5 control panel
DY-1/ARR-2X dynamotor (14-vdc)
ID-24/ARC-5 dial (.19 to .55 MHz) for control box/panel (except C-744/ARC-5)
MT-4/ARR-2 control box mount, if C-26/ARC-5 is used 
MT-411/ARC-5X single receiver mounting rack (14-vdc)
MT-5/ARR-2 shock mount
ARC-6151 (MC-215) tuning spline

For local control, a C-24/ARC-5 local control adapter and ARC-6743 tuning
knob are substituted for the remote control units/mount, and tuning spline.

R-148/ARC-5X units are rarities, as are the associated DY-1/ARR-2X and
MT-411/ARC-5X.  Modifications to any AN/ARC-5X component would destroy
most of the value.

The R-23A (and the R-148 equivalent) are redesigns of the earlier R-23
to provide greater receiver output for weak signals and broader AF output
fidelity.   The older R-23 should have, after alignment, the first IF
coil coupling rod positioned DOWN and the other two IF coils UP.  In
the R-23A and R-148, all three IF coupling rods are positioned DOWN
after alignment. 

FWIW, the various ARA, SCR-274-N, and AN/ARR-2-AN/ARC-5* receiver racks
(except for the MT-7/ARR-2) are mechanically and electrically identical
between the three systems.  One small exception:   The AN/ARR-2 and AN/ARC-5
racks have switch lock-wire anchoring points stamped on each side of the
rack's AF bus A/B switch.

Mike / KK5F