[Milsurplus] BC-611 Fundamentally Flawed

[Mike Morrow]

Hue wrote:

>You do not have much interoperability with armor. How many armored assault
>vehicles carried HF equipment?

Well, there's the SCR-508!  (20 to 28 MHz)  :-)
I couldn't resist that.  There must have been some great (and surprising)
DX on those sets when the solar activity was good!

>Maybe the 300 set should have been built to tune a lower
>frequency range?

That to me has always been one of the most interesting questions.
Why produce a BC-1000, a set that was very sophisticated for its era,
whose 40 to 48 MHz coverage did not overlap any spectrum covered by
any other tactical FM radio of the time?  As Robert mentioned yesterday,
that gap persisted until the RT-67/GRC appeared in 1949.  

It would have been as easy to make a version covering, say, 27 to
35 MHz to overlap other sets such as the SCR-508 and SCR-608.
I can only guess that frequency congestion was a persistent problem,
and that the SCR-300 was the initial entry into that old philosophy
of assigning three separate frequency ranges to the major components
of the army:  20 to 28 MHz to Armor, 27 to 39 MHz to Artillery, and
38 to 55 MHz to Infantry.

>The BC-611 COULD have been built to tune 30 Mc/s without too
>much trouble, using overtone crystals.  Of course, to pack an FM
>radio, at that time, into such a package was impossible, or at least,
>VERY difficult and expensive.

That arrived as the 1951 RT-196/PRC-6, which only barely saw any
service in the Korean War.  The RT-196 contains 14 vacuum tubes on
a chassis that occupies only about 35 percent of the volume inside
the handset (the rest is battery space).  Though unjustfiably
disdained today (like all the rest of the so-called Korean War
series of tactical radios), it was a marvel of miniaturization.

The same could be said for the BC-611 in 1941.  Imagine, a one-third
watt plate-modulated MOPA transmitter, a superheterodyne receiver with
RF stage, using only five tubes in a small handset that also contains
all batteries.  For something designed in 1940, that is still pretty
impressive engineering.  Now, if only it wasn't so hard to align.

Mike / KK5F