Qualtiy of wartime voice communications?

In reading a history of Bell Labs History ("Service in War and Peace")
there was a discussion of voice quality over telephone lines and radio
circuits.

In laymen's terms, it appears that due to wartime shortages, quality
was sacrificed to the bare minimum to handle more calls.

In technical terms, for telephone communications, they narrowed the
bandwidth normally available for voice calls from 3 KHz to 2 KHz. This
enabled them to squeeze more calls over a single line.
I don't think local calls would've been affected, but long distance
calls over a great distance would've been of poor quality. (How much
so I can't say. The history said the frequency that was cut out was
the least important for voice calls.)

Of course, in those years long distance telephone was quite expensive
and infrequently used by everyday people. Servicemen did splurge on
one last call home before shipping out and business people and govt
made calls for war contracts. Despite the expense, long distance lines
were jammed during the war and the Bell System ran frequent
advertisements asking people NOT to make long distance calls and to
keep them short. Operators would break into long conversations and ask
the parties to end the call.

In military radio communications, they also made the bands narrow and
squeezed them close together. This required that the components of
radio transmitters and receivers had to be much better than in the past
(tighter performance tolerances) so that the narrow frequencies would
be properly accessed. Manufacturing the radio sets proved to be a
challenge because performance tolerances were so high.

I wonder how well the radios worked in the field. However, the history
notes that Bell Labs prepared special headsets and microphones
specially for combat or other constrained use (ie while flying a plane
or driving a tank during high noise).


This history is interesting, though written in a dry style. It also
covers Bell Labs work in fire control computers for anti-aircraft guns,
radar, public address systems, and air raid sirens. Post WW II work is
included as well.



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