[ARC5] tuning knobs (and local controls)

[Mike Morrow]

I wrote:

>The standard part number for the local tuning knob is A.R.C. 6743.  Have you
>examined one?  If an exact (or even just a very close) reproduction were to be
>custom made in small quantity, I believe each would cost well above $100.

Just to make sure we are all talking about the same thing, the proper A.R.C.
6743 local tuning control is shown reasonably well on the R-24/ARC-5 receiver
pictured at at http://upload.wikimedia.org/wikipedia/en/8/80/ARC-5_NAV.jpg .
The A.R.C. 6743 is appropriate for the RAT, RAV, ARA, SCR-274-N, and AN/ARC-5.

Anything else, such as the A.R.C. test kit knob mentioned in recent postings,
and those commercially-made controls with a plastic knob (such as shown at
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160307360838 ) are not
properly part of any receiver in military configuration.

>There's the other standard tuning knob, the A.R.C. 9554.  This is actually
>a local tuning key that is screwed on a storage base on the tube cover of the
>AN/ARC-5 receivers only.  It was officially supplied only with the stabilized
>communications receivers (R-25, 26, 27), which were designed to be lock tuned.
> ... it would be very marginal for routine use because of loose engagement of
>the tuning spline and small knob diameter.  The navigation receivers (R-23, 24),
>never lock tuned, were not officially supplied with the 9554 key...

An A.R.C. 9554 is now on ebay, presented as an "SCR-274N" (it isn't) "connector" 
(it isn't).  But the item description includes a very good photo.  See:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230316903316 .

A "complete" R-25, R-26, or R-27/ARC-5 should have a 9554 and a remote control
box dial stored under the tube cover.  The R-23 and R-24 should not have a 9554.
The 9554 is NOT properly part of the RAT, RAV, ARA, or SCR-274-N systems, since
those systems did not employ stabilized lock-tuned communications receivers, nor
is there a storage base on the tube cover for it.

Mike / KK5F