[ARC5] A.R.C. Type 21 (AN/ARN-59)

[Mike Morrow]

Gordon wrote:

> What was really amazing was the later ARN-30 receiver, 180 channels, 
> crystal controlled, in the same form as the AN/ARC-5 receivers, though 
> internally they were not alike. A.R.C. put a great deal in a small 
> package - before transistors.

Another amazingly compact vacuum-tube A.R.C. set (rather smaller than the
R-1021/ARN-30D mentioned above) is the Type 21 ADF set (R-30A), which
under the JAN system is the R-836/ARN, part of AN/ARN-59.

This small ADF set uses wire-in sub-miniature tubes, except (IIRC) one
transistor for the BFO.  It was adopted by the U.S. Army in 1957, but
components were still being made for it on contracts in the 1970s, such
as the PP-4328/ARN-59 transistor HV supply that replaced the DY-150/ARN
dynamotor.

BTW, there's a mildly interesting U.S. Army report of 1964 ADF testing at: 
    http://www.dtic.mil/dtic/tr/fulltext/u2/a030812.pdf  .

The A.R.C. Type 210 VHF com set (360-channel) is also a pretty interesting
late 1950s design, especially the RT-11A transceiver unit.  Its design relies
heavily on vacuum tubes.

Mike / KK5F