Film dial scales (was Re: [Milsurplus] Russia vs. US)

Tue, 4 May 2004 14:04:29 -0400

Film scales are not the same as the optical projection scales, which are
precision etched or printed on glass and then projected with a rear light
and lens system onto a front panel display. The film scale is just a
mechanical way to extend the available panel space to provide the user with
a long scale. Examples of film scale are the Racal RA17, RA117, the MacKay
3010 and the British military R210 receivers. These are not projected but
directly displayed.

The rear projection scale with the magnification effect (like in the US SRR
series receivers) originated with German radios from WW2, as mentioned by
Tom Bryan. Some examples of this technology are the Russian R309, R326 and
R250 series receivers and the older R107 series VHF transceivers.

As to Ray's Russian R311 receiver - I have one of these, it's a fairly
decent receiver for a late 40's-early 50's military field receiver (I look
at it as sort of the equivalent of our AN/GRR-5 receiver). It doesn't look
like it's related to a German design in particular, it just has that general
European character, which is shared by German, Italian, French, Russian and
even Czech (I have a Czech military receiver from the 50's, model R-4) and
to a certain extent some British equipment of the era.  BTW the R311 has a
"normal" dial...

In some aspects the R250M receiver I own looks like it could have been built
by Collins...

73, Meir WF2U
Gowensville, SC

 -----Original Message-----
From: 	[email protected]
[mailto:[email protected]]  On Behalf Of
[email protected]
Sent:	Tuesday, May 04, 2004 10:58 AM
To:	[email protected]
Subject:	Film dial scales (was Re: [Milsurplus] Russia vs. US)

I remember a Bell System test oscillator - occupied the top of a five foot
rack - that had a film scale about 20 feet long.  So you could read the
frequency pretty accurately without the aid of a counter.

--

jhhaynes at earthlink dot net

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