[Milsurplus] RBK-1

[WA5CAB at cs.com]

First, a correction (after I read the table more carefully).  It skips RBK, 
RBK-2, RBK-10, and RBK-15.  This isn't uncommon (for the Navy to skip model 
numbers for one reason or another).  Sometimes the numbers got picked up on 
rebuild/modification contracts, as the Signal Corps did with BC-348-S.  LM-21 is 
only thing that comes to mind right off, but I know I've seen others.  Perhaps 
the RBK-15 was such.

In any case, the "odd" Navy connector is 49120 (chassis to wire) and 49121 or 
49121-A (cable).  I have several of the latter and one of the former left.  
Condition Used Good (the cable connectors were on jumper cables, two to a 
cable).  Otherwise, the only chassis ones I have are feed-through adaptors, Navy to 
UHF Female.  FYI, the original compliment of accessories with at least some 
AN/URM-25 models included a Navy to BNC adaptor.  Handy thing to have.

Also, the wierd slot and groove in the side of the cable connector isn't for 
twist-lock retaining.  The plug just plugs straight in.  The longitudinal slot 
and circumferential groove allow the OD of the insertion end of the connector 
to be slightly larger than the ID of the chassis connector (to give a spring 
compression fit).

In a message dated 7/5/2005 8:30:07 AM Central Daylight Time, 
ka1kaq at gmail.com writes: 
> >I don't know for sure as the only RBK manual I have is for RBK-16.  But it
> >has a model comparison table covering everything up through the -16, and 
> says
> >that up through -15, all models had three antenna inputs (one for each 
> band)
> >like the Signal Corps BC-787 models that I've seen or seen manuals on do.
> 
> I recently picked up a -15 and -16, they are (were) both set up for
> that odd Navy (General Radio?) antenna plug. Also have a -13 and all
> models I've seen earlier did indeed have the separate inputs. No idea
> if the -15 was modified or updated, but it looks like it was
> originally done that way. I'll do a side-by-side.
> 
> >Unfortunately, it does not say what connectors were used. 
> 
> Is this connector the CN 49121 or ? Has a weird slot in the side and
> makes a quarter-twist to lock onto the receptacle.
> 
> >My guess is that if the
> >Navy wanted it to have some specific connector or connectors, they would 
> have
> >ordered it that way.  And if the Navy had modified any significant number 
> of
> >the earlier sets, it probably would show up in the table.  The RBK-16 alone 
> is
> >listed with one coaxial antenna input connector.
> 
>   Hmmm....makes me wonder now if my -15 was modified by them?  I need
> to find both the connectors and the socket, since someone removed the
> socket from the -15 (probably because they couldn't find the correct
> connector). Fortunately they didn't hack up the set to do so, just
> left the antenna wire hanging.

Robert & Susan Downs - Houston
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