[Milsurplus] USN RBM vs. RBS Questions

[LI WHA HO WALLY]

Hue, As you know the RBM consisted of two receivers
... One for LF and a 2 to 20 mc HF... The RBS is
almost the same as the RBM HF... The IF freqs are
different... The RBS is 455 and tne RBM HF is 1255 kc
I think... The schematic diagrams are the same even
down to the part numbers.. The Navy had an RBS abord
every ship, it  was  
used to receive time ticks to check the ship's
chronometers... The dials are marked because non-radio
people operated them.. They had no speakers, only
fones with long leads... I own an RBS, but I have no
manuals for either the RBM or the RBS.. Yes, the RBM
was used ashore with the TBW by the Marines... 73's
K5op  WALLY





--- Hue Miller <kargo_cult@msn.com> wrote:
> 
> ----- Original Message -----
> From: "Morrow, Michael A." <mamorrow@tva.gov>
> 
> 
> > I have no manuals for either, so I was wondering
> what actual differences
> > exist between the RBM and the RBS receivers.  I've
> noticed only:
> > (1)  Name plate (of course),
> > (2)  Tuning lock on the RBS that isn't on the RBM,
> > (3)  Control knobs engraved with first letter of
> the control's function on
> > the RBS.
> >
> > Everything else appears identical, so I'd be
> tempted to assume that the
> > circuits would be identical.
> 
> Letter-marked knobs on RBS are the only difference.
> I think that's
> radium paint, the B, T marks on the knobs. Also, you
> will never
> see an RBS with the scrolling-towel logging chart
> thing.
> >
> > Aside from that, what transmitter was normally
> used with the RBS,
> 
> No transmitter! Auxiliary equipment= the splashproof
> cover for
> outside mounting, and the "big" PS with audio power
> amp.
> 
> >and what  was the general nature of the
> installations for which it was designed?
> 
> So far, it seems the RBS with the big PS and splash
> cover case
> was intended for "alert-circuits", kinda like the
> army's SCR-593
> (right nomenclature) or later GRR-5.  "5 bogies
> reported our way,
> NE, estimated 10 minutes", that kind of thing.
> But most reports, and all the photos available, seem
> to only show
> it as just an auxilliary communications receiver,
> right in the
> radio room, not out on the bridge.
> I have my doubts on how great this might have worked
> as an
> alert receiver. The calibration is not very good,
> and the dial tuning
> is much too fast. I suppose the wide band with the
> selectivity in
> that position took care of that. Also, i don't
> recall that the HF receiver is very stable either.
> In
> its favor, Uncle Sam paid $1000
> WW2 dollars for each - a whole lot of money, and it
> looks good,
> nice architecture, very high quality construction, a
> smart circuit
> diagram, quality overall. It's just that the tuning
> is not very good.
> I suppose that's in keeping with how the military
> actually used
> most of their receivers....just set to frequency and
> dial locked.
> For actually using, for my money, the LF/MF receiver
> is much more usable.
> Hue Miller
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