[ARC5] ARC-5 Transmitter Crystal Summary

[J. Forster]

Let me see if I can put the various pieces of this puzzle together. The original
question was whether there was a 'standard' set of crystals for the ARC-5 type
radios.

Mike Hanz's wonderful site:

http://members.cox.net/aafradio/flightdeck/flightdeck.htm

lists the frequencies as follows:

"Shown here is the entire suite of 8 MF and HF transmitters in the ARC-5 set.
Frequency ranges, along with the most common
calibration crystal frequencies, are shown below. (Be aware that the SCR-274N
and Navy ATA sets had different "standard"
crystal frequencies.)

T-15 500-800 kHz (Calibration crystal 800 kHz)
T-16 800-1,300 kHz (Calibration crystal 1,300 kHz)
T-17 1,300-2,100 kHz (Calibration crystal 2,100 kHz)
T-18 2.1-3.0 MHz (Calibration crystal 2,601 kHz)

T-19 3.0-4.0 MHz (Calibration crystal 3,265 kHz)
T-20 4.0-5.3 MHz (Calibration crystal 4,435 kHz)
T-21 5.3-7.0 MHz (Calibration crystal 5,505 kHz)       [ I have an example]
T-22 7.0-9.1 MHz (Calibration crystal 8,870 kHz)"

For the SCR-274-N, from TO 08 10 50  Feb 5, 1943:

3 to 4    mc    3500 kc
4 to 5.3 mc    4600 kc         [I have an example]
5.3 to 7 mc    6200 kc         [I have an example]
7 to 9.1 mc    8000 kc

This corresponds to what Robert Downs said:

"The SCR-274-N parts list gives 3500, 4600, 6200 and 8000 KC."

But he goes on:

"I have also had 5205 and 5500 DC-8's.  The ATA/ARA manual adds 2500 KC."

>From this I conclude the following:

There is a 'standard set' for the ARC-5  (Navy)
There is a different 'standard set' for the SCR-274-N  (Army and USAF)
There is an unknown number of other frequencies, suck as 3885 kc, that are
channel specific, perhaps for the O-4

Does this seem correct?

Thanks,
-John