[Milsurplus] RBM/RBS

[Hubert Miller]

The receivers may all have the same dial "distance" like the 1/2 inch or 
so you mention. HOWEVER, the gearing to the tuning capacitor varies.
The BC-312 and BC-348 have low speed gear ratios, so they take many more 
turns of the tuning knob to cover the same number of kHz - or
distance on the dial. You can notice this even on the RBM-mf altho 
there, the receiver is saved by the much narrower bands, like, i think, 
the
top band on the RBM-mf is something like 1.2 - 2 MHz.
The IF on the BC-652 is 915 kHz. The RBM-hf IF is 1240 kHz. The "BROAD" 
selectivity position has no use for current-day users. Maybe if
broadcasting goes fully digital, it might make a useful front end.
-Hue

 >I appreciate all the comments on these receivers, especilly since I 
have 2 or 3 of eack.  Asside from the broad frequency response, I don't 
see much difference in the dial mark spacing between the HF version of 
the RBM / RBS when compared with their contemporany receivers.  The RBC, 
BC-348, BC-342, all cover the 20 meter band in 1/2 to 3/4 of an inch or 
so.

As for the broad frequence response, most receivers were pretty broad if 
I remember right.  Someone mentioned the BC-652 and I had one of them 
running off the dynamotor over Christmas and it did a passable job on 
SSB, but much better for AM and CW.

One comment got me wondering about the RBM though.  Since it was more or 
less supposed to be used with the TBW, is the power supply frequency 800 
cycles?

73,
George