[Milsurplus] R-388/51J use

[radioman390 at cs.com]

The R-390 (or 390A)was not an SSB receiver without an external adapter running off the IF output, so in that respect they were functionally equal. At one time I had 2 of each, and for BC DXing (AM MW broadcast band pickup of Europe, Africa and Near East stations) I preferred the earlier R-390.

One 390A issue was the mechanical filter pinging on adjacent channel peaks. The R-390 had two RF amplifier stages of amplification before the mixer, and SIX IF stages. I've been told that the IF coils were so sharp, that they used resistors in each IF can? to reduce the "Q" to make it audible. 
The 51H3 was as I recall, a fixed freq receiver (crystals controlled) but did have a SSB detector.
73
KD2BXA

 

 



-----Original Message-----
From: C.Whitaker <whitaker at pa.net>
To: milsurplus <milsurplus at mailman.qth.net>
Sent: Sat, May 26, 2012 4:11 pm
Subject: Re: [Milsurplus] R-388/51J use

 
 
 
de WB2CPN 
I suppose you all know that Art Collins and 
General Curtis LeMay were close friends. 
Arthur Godfrey was part of the trio. 
That's howcome SAC started using SSB 
instead of AM.   There was a live test of 
both modes on a B-36, SSB won hands down. 
R-388 or 51J, whatever, was much lighter, 
easier to maintain, and a lot less cost, than 
the R-390.  My old USAF command, used 
the 51J in the Tech Controls, and the receiver 
and transmitter sites.  Only for quality control. 
A lot went to overseas State Department sites, 
mostly for morale and welfare.   FBIS used 
a few of them I know.  We did some maintenance 
work for them one time.   My pictures of a GRC-26 
show R-388 in the wood cabinet. 
SP-600 was a good radio, I modified one for 
SSB, but they are noplace without a freq meter. 
The first Collins transmitter I saw was the 32RA. 
Almost every AF control tower had one for HF. 
That was at the end of WWII.  All the large HF 
Autotune transmitters were by Collins.  Most 
had BC names, but the manuals were Collins. 
A chrome plated, restored, with three mechanical 
filters, 51J-3/4 would be a joy to have. 
73  Clete 
+++++++++++++++++++++++++ 
 
 
On 5/25/2012 4:27 PM, Mike Morrow wrote: 
>> I recall the introduction of the original 51J in a small trailer ... 
>> viewed by invitation only.  No other receiver like it anywhere. 
>> Sure blew the 348 away. 
> That's like saying the Collins KWM-2A (AN/FRC-93) sure blew the RCA ARB/ATB 
> away.  But these sets were from two different eras serving two very different 
> functions. 
> 
> The BC-348 design dated from 1936 and was solely intended for aircraft use. 
> The 51J (R-388/URR) came about 15 years later for stationary or 
> transportable/stationary installations. 
> 
> Comparing the USAAF BC-348-* (AN/ARR-11) to the 51H-3, the commercial model 
> number for the USN AN/ARR-15, would be more reasonable. 
> 
> I've never seen a unit marked 51H-3, and I've also never seen its matching 
> transmitter marked 17H-2.  That was the commercial designation for the 
> AN/ART-13.  I have a manual for the 17H-2, but not the 51H-3. 
> 
> 73, 
> Mike / KK5F 
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