[ARC5] [Milsurplus] More ARC-5 Questions - Receiver Control Box Dials

[Mike Morrow]

>There are Aluminum and Bakelite dials for the receivers, transmitters,
>and control boxes...

WECO used some sort of composite material for *some* of their SCR-274-N
sets, but I've never seen anything but metal used for the control box dials.

Receiver control box dial nomenclature:
     SCR-274-N               AN/ARC-5
MC-212 (190 to 550 KC)  ID-25/ARC-5 (.19 to .55 MC)
MC-415 (.52 to 1.5 MC)  ID-26/ARC-5 (.52 to 1.5 MC)
                        ID-27/ARC-5 (1.5 to 3.0 MC)
MC-213 (3.0 to 6.0 MC)  ID-28/ARC-5 (3.0 to 6.0 MC)
MC-214 (6.0 to 9.1 MC)  ID-29/ARC-5 (6.0 to 9.1 MC)

The SCR-274-N control box dials are sharply sloped under the area of
the dial on which the frequency markings are printed, so the frequency
scale is only 0.25 inches high.  Markings are small, fine, and non-luminous.

The AN/ARC-5 control box dials are much less sharply sloped under the
area of the dial on which the frequency markings are printed, so the
frequency scale is 0.5 inches high, twice that of the SCR-274-N units.
Markings are large, broad, and (at one time) luminous.  A great inprovement.
 
Original ARA control box dials did not have anything other than an A.R.C.
part number assigned.  They were identical to the SCR-274-N dials, but included
a 1.5 to 3.0 MC unit.  However, I've never seen an ARA receiver control box that
did NOT have the later AN/ARC-5 type of dials installed.  That is, I believe,
a testament to the much greater legibility of the AN/ARC-5 dials over the
original design, for those ARA sets still in service after the improved dials
became available.

Mike / KK5F
(Looking for an MC-415 for my SCR-274-N with AN/ARR-1 combo.)