[Milsurplus] R-584

[WA5CAB at cs.com]

I've never actually had any of the receivers so I can't comment on the 
legibility of the nomenclature on the nameplate, although the one closeup photo is 
the manual is clear enough.  But it is R-584/MRC-20.  Ref TM 11-692, Radio Set 
AN/MRC-20 March 1954 (AKA T.O. 31R2-2MRC20-14).

According to the manual, R-584 is a modified BC-348-Q OR BC-348-R.  The 
for-sure way (because some of the other differences were often ham-hacked) to ID 
the parent receiver is to look at the BFO coil.  The BFO coil in the BC-348-JNQ 
was mounted behind the front panel and direct driven by the front panel knob.  
The coil in all other models (and all BC-224's) is mounted to the top of the 
chassis, looks like the IF cans, and is driven by a flexible shaft with the 
knob mounted to a shouldered shaft in a bushing in the front panel.  The photos 
in the manual show a modified BC-348-R and a modified BC-348-Q.

Modifications to convert the BC-348 to R-584 consist of the addition of an 
outboard (mounted on top of the cabinet) Squelch and Noise Limiter module.  The 
module is connected to the receiver through an AN connector installed at the 
left end of the front panel.  Exactly where it was installed depended upon 
which model of BC-348 was modified.  The AN connector, Squelch Module and 
nameplate are the only externally visible modifications.

Without commenting on the quality of the free downloads, I'll mention that I 
have decent hardcopy reprints available of the final manuals on all of the 
BC-348 models.   And could add the R-584 modification information from TM 11-692 
to either the JNQ or HKLR manuals if needed to make them complete R-584 
manuals, as I did when I built the R-808/GRC-14 and several other manuals.  But 
TANSTAAFL.

In a message dated 12/30/2007 10:31:07 AM Central Standard Time, 
kk5f at earthlink.net writes: 
> >Need information on the R-584/MRC-20 receiver...
> 
> Is it definitely a R-584, and not a R-589?  I've never seen one, but I've 
> heard that the nomenclature marking was sloppy on these units, and R-589/MRC-20 
> is the actual nomenclature.  It is a modified BC-348-R with, I think, an 
> added front panel connection to an external noise limiter/squelch circuit.  If 
> so, the schematic is likely almost identical to the BC-348-R except for this 
> new connector.  The manual for the BC-348-R can be found free for download at:
> 
> http://bama.edebris.com/manuals/military-kg7bz/bc348/

Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
<wa5cab at cs.com> (Primary email)
<wa5cab at comcast.net> (Backup email)
   
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