[ARC5] CR-1A/AR et al

[Mike Morrow]

Robert wrote:

> DC-30 was replaced by CR-1/AR which must have pretty quickly been
> replaced by CR-1A/AR, which later became CR-1B.

The CR-1A/AR and the CR-1B/AR existed concurrently.  The CR-1B has inferior temperature drift characteristics, compared to the preferred CR-1A.  For example, the Maintenance Instructions for the AN/ARC-1 has this to say about crystal locations:

"The radio transmitter crystal unit (9.72-megacycle unit) and one of the guard-channel crystal units are located inside the radio transmitter-receiver chassis where the temperature is such that Crystal Units CR-1A/AR must be used for satisfactory results.  The other 10 crystal units are located under the front cover where they are not subjected to as high temperatures and either Crystal Units CR-1A/AR or Crystal Units CR-1B/AR may be used."

These crystal units are part of a confusing array of designations.  The AN/ARC-3 uses the CR-1A/AR, but its instructions also lists these other equivalents:

DC-11-A
DC-16-A
DC-26-A

The AN/ARC-3 instructions do NOT list the DC-30, CR-1/AR, nor the CR-1B/AR.

Mike / KK5F