[Milsurplus] BC-348 thoughts

[Hue Miller]

Was looking at "THE SURPLUS HANDBOOK"  "VOLUME 1 Receivers
and Transceivers"  ( no further volumes were published, AFAIK ), by
Caringella and Clark, 1959. There is a photo of a BC-348. I note that
in the upper left, where some versions have a CW OSC  ON-OFF knob,
this one has a "hole cover" plugged in, and below it the CW OSC ON-OFF
toggle switch, as on other versions. How explain this manufacturer change?
>From the photo it's apparent this is not a post-military hammy mod. The
nameplate in the photo, the receiver number is obscured by paint or some-
thing so you really cannot tell what version this was. Very oddly, it looks like
from the photo, the nameplate was pried off, and then maybe just glued back
onto the front panel for the photo, and crooked too. ( Yes, there are some 
slapdash attributes of this book, for example using the same photo of a 
BC-344 for both the BC-314/344 and BC-312/342 pages - except one photo
has too much light exposure. Very professional job.

Now re the "cheapo versions" ( is that what Robert Downs called them? )
versus the "premium edition":

1. What is the logic behind going to the triode connected 1st RF? 
Is it that the more modern tubes did not need all that much RF gain?
I judge that the resistor in the "triode" plate loads down the plate tuned
circuit enuff that self-oscillation with the triode connection is obviated.

I also judge that the premium edition, not having the resistor loaded-down
tuned circuit, would have slightly better RF selectivity. ( Perhaps this is more
a point of finesse and not really that apparent in specifications. )

2. The cheapo version lacks the voltage regulator. Hmmm....that would seem
to be a disadvantage.

3. The premium edition has between the mixer plate and the 1st IF, a full 3 
tuned LC circuits, in a conventional shortwave-radio crystal filter circuit. The
cheapo version has only one LC circuit, an autotransformer deal. Therefore,
the premium would have better selectivity. Also by adjutsting the LC circuit
right next to the 1st IF grid, you can align the set to the selectivity bandpass
degree you wish, to its limits of course, by shifting the resonance point of the
tuned circuit, thus varying the impedance load to the crystal filter. This is the
way the HRO selectivity control works, by making this adjustment front-panel
variable. That seems like another advantage. 

I can understand that this was war-expendable material, needed to be simplified
as long as it could still accomplish the task. ( Heathkit knew the process also. )

If there had been a "U" version, the schematic for the late-version, the simplified
one, could have been labeled "BC-348JUNQ"
-Hue Miller