[Milsurplus] National RCQ/RCP information

[Telegrapher at att.net]

 I sent the following to Jason, kf6pqt after i saw the picture of his receiver.  I think this unit has had questions about it on here or boatanchors before and no one had an answer.  I found the original RCQ manual in my stash.  I saw one of these at a swapmeet here locally several years back and no one seemed knew anything about it.  Needless to say there were no buyers either!

Jason's pictures of this and other goodies can be found at the link towards the bottom of the page.  
-
> In your pictures you have a picture of a National receiver setting on top
of a Johnson Ranger cabinet. The receiver appears to be a National RCQ
Communications receiver for the Civil Aeronautics Administration.  While it
was built by National Company, Inc. of Malden, Mass., it was modified for
CAA service by National Electrical Machine Shops, INC. in Silver Springs,
MD.  Contract number Cca-26227, Feb. 5, 1948

> Comparing pictures of yours with what the manual shows it to be, where the
> two lights appear on your front panel, on the left side of the original
> radio was the National/Military data plate and on the right side where
yours
> has a light there was a tuning log form.
>
> The receiver was originally a type RCK or RCL.  It was redisegnated when
the
> modifications (listed below) were incorporated.
>
> An additional modification was performed by the FAA Facilities Material
> Division in OKC that changed the designation from RCP/RCQ to
 RCP-1/RCQ-1.
> This mod consisted of adding an alarm buzzer, disconnection of the link
> panel A22 and receiver silencing circuit components R41 and A14.
>
> A: The high frequency Oscillator was modified so that it may be either
> crystal controlled or tuneable as selected by a switch on the front panel.
>
> B: The AVC Circuit has been completely changed to correct several
> conditions.
>
> C: The CONS circuit (?) has been changed to the type which incorporates a
> relay operated CONS which mutes the receiver to any desired level in the
> absence of a signal.
>
> D: The Sharp-Broad control has been deleted and the receiver left in the
> broad position for transformers T3 and T5 with Transformer T4 in the sharp
> position.
>
> E: To facilitate the AVC and CONS circuit changes explained above, the 2nd
> detector circuit has been changed, the
 original 6C5 detector tube being
> replaced with a 6H6.  One section of the 6H6 is utilized as a diode
detector
> withe the other section being used in a series type noise limiter.
>
> F: In order to redice tje interference from static crashes, transients and
> other noise peaks, the second section of the 6H6 tube is connected between
> the diode detector and the first audio amplifierin a series type noise
> limiter.
>
> Apparently it was used mainly for the frequencies of 3105, 4495 and 6210
> Kc.s.  Several paragraphs of discussion on the type of antenna to use with
> it indicated that a quarter wave length, which included the length of the
> ground wire attached to the receiver as well as the wire incorporated in
the
> leadin would be around 75 ft for 3105/3117.5, 52 ft for 4495 and 37.5 ft
for
> 6210 Kc.  Very common Airways frequencies startin back in the
 late 30's early 40's.
>
> I have the manual for this receiver along with some additional modification
> papers.
>
> Larry
> W0OGH
>
> --... ...--
> http://en.wikipedia .org/wiki/ Junk_box
> http://kf6pqt. net
> http://www.flickr. com/photos/ kf6pqt/

--... ...--
http://en.wikipedia.org/wiki/Junk_box
http://kf6pqt.net
http://www.flickr.com/photos/kf6pqt/

      
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