[ARC5] Questions on the R-25/ARC-5

[Mike Morrow]

Ken wrote:

> 1) Is there any definitive information on how many of these were built?

The R-25/ARC-5 is simply an advance on the original ARA CBY/CCT-46104 1.5
to 3.0 MHz command receiver (which was itself originally part of the RAV
liaison receiver system).  The T-18/ARC-5 is likewise an advance on the
original ATA CBY/CCT-52232 2.1 to 3.0 MHz command transmitter.

I don't have any numbers, but there were doubtless many thousands of the
R-25/ARC-5 and the associated T-18/ARC-5 made, based on the notes found
in several places on Figure 8-55 of the AN/ARC-5 LF/MF/HF Maintenance
Instructions Handbook AN 16-30ARC5-2:

---Quote---
1.  A 190-550 Kc. receiver, R-23/ARC-5, is supplied to the airplane
contractor for installation.  Receivers R-26/ARC-5 and R-27/ARC-5 are
supplied to the Service in quantities of one for each airplane.
Receiver R-25/ARC-5 is supplied to the Service in quantities of one
for each five airplanes or one for each airplane depending upon the
type of aircraft in which this equipment is installed...

2.  A 3.0-4.0 Mc. transmitter, T-19/ARC-5, is supplied to the airplane
contractor for installation.  Transmitters T-20/ARC-5, T-21/ARC-5,
T-22/ARC-5 supplied [sic] to the service in quantities of one for each
airplane.  Transmitter T-18/ARC-5 is supplied to the Service in quantities
of one for each five airplanes, or one for each airplane depending upon
the type aircraft in which this equipment is installed.
---End Quote---

It makes sense that the aircraft contractor was provided with the R-23*
and T-19/ARC-5, doubtless for ferry service on the Adcock beacons and
the tower frequencies near 278 kHz receive and 3105 kHz transmit.  A
C-26 or C-125/ARC-5 for the R-23* would have been installed for pilot
tuning of the R-23 as required in flight.

> 2) WHY were they built? What was their original purpose?

Judging from the many US Navy and US Army radio sets whose lower limit
of operation was 1.5 MHz, it seems reasonable to have provided some
limited capability for use of these MF regions.  The frequencies below
3.0 MHz have always been associated with maritime and naval operations.
Providing this capability seems less silly than, say, having restored
loop antenna connections to the R-23* and R-24/ARC-5 navigation 
receivers. :-)

73,
Mike / KK5F