[R-390] R-391/URR (MOD) - Direction Finder Set AN/FRA-44 --- Receiving Set AN/FLR-7

[Clay Curtiss WA7KBR]

Tom,
My unit still has the plate over the bandwidth switch position.  Also, it
doesn't have a BFO Pitch knob.  The BFO Pitch shaft is recessed behind the
front panel and has a slot in the shaft for screwdriver adjustment.  It
would appear that this R-391 must be in the original (as modified by RCA)
configuration.

Now I need to decide how much time I want to invest in a receiver with such
specialized application.  If the IF selectivity is indeed 60kHz as suggested
by Wally (K5OP), then the receiver will have limited utility for AM QSO's
and SW listening.  I suppose I could look for a standard IF to swap, and
keep the original one for some future owner.  What's the group consensus?
Is this a receiver that only a hardcore collector could really appreciate,
or is it of general interest to the members of this list?  Comments anyone?
My long term interest is to own a nicely cared for, and well functioning
R-390/391 that would be used on a daily basis.

Clay


----- Original Message -----
From: "Tom Norris" <r390a@bellsouth.net>
To: "Clay Curtiss WA7KBR" <wa7kbr@curtiss.net>
Sent: Wednesday, January 28, 2004 10:47 PM
Subject: Re: [R-390] R-391/URR (MOD) - Direction Finder Set AN/FRA-44 ---
Receiving Set AN/FLR-7


> I *think* ( And I can't find my notes on this! ) that mod
> simply put a plate over the bandwidth switch position and
> stuck a fixed IF bandwidth deck in there. If you have
> a bandwidth control on  the left side and everything
> else seems normal, you should not have to do anything -
> it's most likely has had that IF deck replaced with a normal
> one. Ought to be good to go as-is.
>
> Tom Norris KA4RKT
>
> >Hi,
> >I'm new to the list and looking for some advice on an R-391 (S/N 145)
that I
> >have.  It was an original 1951 Collins unit (contract 14214-PH-51-93) and
> >was modifed by RCA for the Navy and has an additional 3"x2"metal tag on
the
> >front panel below the function switch.  It reads as follows:
> >
> >R-391/URR (MOD)
> >RECEIVER, RADIO
> >-------------------------------------------------------------------------
> >A UNIT OF DIRECTION FINDER SET AN/FRA-44 (XN-1)
> >COUNTER MEASURES RECEIVING SET AN/FLR-7 (XN-1)
> >-------------------------------------------------------------------------
> >MODIFIED FOR
> >NAVY DEPARTMENT - BUREAU OF SHIPS
> >BY CONTRACTOR
> >RADIO CORPORATION OF AMERICA
> >CAMDEN, NJ
> >CONTRACT NObsr 81315
> >US
> >
> >I've searched this list's archives, but find no mention of it.  I tried
> >google and came up with a reference to Antenna AN/FLR-7 on www.r-390a.net
in
> >the FAQ as follows:
> >
> >This Wullenweber antenna, also known as a Circularly Disposed Antenna
Array
> >(CDAA), consisted of a large number of 200 foot towers arranged into a
ring
> >more
> >than 1300 feet in diameter.  An inner ring of shorter towers competed the
> >array.
> >The antenna reportedly operated from VLF well into the VHF frequency
range.
> >It
> >provided direction finding accuracy to within two or three degrees,
> >according to
> >some reports.
> >
> >When I first got it, it worked but always had ringing in the audio.  I
> >suppose it could have been modified to have a very narrow IF bandpass.
> >
> >Does anyone have any info on how this R-391 was modified by RCA?  I
suspect
> >that there weren't very many of these made, and I don't know if it is
rare
> >enough or interesting enough for anyone to care about.  Would it be best
to
> >leave a unit like this in it's current configuration, or to try to
convert
> >it back to a stock R-391 again?
> >
> >
> >Thanks for any and all help.
> >
> >Clay
> >WA7KBR
> >
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>