[Milsurplus] USN RBM vs. RBS Questions

[Hue Miller]

----- 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