[R-390] R-391/URR (MOD) - Direction Finder Set AN/FRA-44 --- Receiving Set AN/FLR-7
Clay Curtiss WA7KBR
[email protected]
Wed, 28 Jan 2004 15:05:09 -0800
Hi Bob,
I know very little of it's history. I acquired it from another ham 15-20
years ago. He was in the military and being transferred, so he didn't want
to haul it with him. I checked and his license is still current and he's
living in my area again, so I might contact him and see what he remembers,
if
anything, about the unit.
I have discovered a little more about the receiver itself. It was part of a
NRL project called Project Boresight. It received an NRL Innovation Award
in 1998 (http://www.nrl.navy.mil/NewsRoom/images/75awards.pdf). Here's
part of the text:
During the 1950s and 1960s, NRL demonstrated technology that permitted
a radical improvement in the performance of high-frequency direction
finding (HFDF) networks and oversaw the deployment of this technology
in Project Boresight and Project Bulls Eye.
The first of three innovations that underlay this work was retrospective
direction finding. Previously, all stations in an HFDF network were
required to measure characteristics of the same signal while
transmission
was still occurring; after-the-fact easurements were needed. Previous
attempts at NRL1 and elsewhere were limited by storage bandwidth and
recorder instabilities. Recording significant fractions of the HF
spectrum and using a digital method for overcoming recorder
instabilities
enabled retrospective DF. This was the basis of the 1960 quick-reaction
Project Boresight that deployed the AN/FLR-7 and AN/FRA-44
worldwide.
Project Boresight's crucial contribution to national defense was
recognized by the awarding of the Distinguished Civilian Service
Award to NRL's R.D. Misner and M.J. Sheets.
A reference is also made to the following:
Gleason, R.F. and Greene, R.M., "A Wide-Aperture HF Direction-Finder,"
NRL Memorandum Report 746, October 1957.
If anyone has a copy of this report, please let me know.
Thanks,
Clay WA7KBR
----- Original Message -----
From: "robert J. wagner" <[email protected]>
To: "'Clay Curtiss WA7KBR'" <[email protected]>
Sent: Wednesday, January 28, 2004 9:06 AM
Subject: RE: [R-390] R-391/URR (MOD) - Direction Finder Set AN/FRA-44 ---
Receiving Set AN/FLR-7
> Hi Clay - Sounds interesting - do you know any of the history
> of the radio (i.e. where did it come from, how did you acquire
> it etc). The FRA-44 dates to the early 60s and was unique to
> the Navy. BobW
>
> -----Original Message-----
> From: Clay Curtiss WA7KBR [SMTP:[email protected]]
> Sent: Wednesday, January 28, 2004 12:27 PM
> To: [email protected]
> Subject: [R-390] R-391/URR (MOD) - Direction Finder Set AN/FRA-44 ---
Receiving Set AN/FLR-7
>
> 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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