[BC] Frequency Measuring

[Rick Levy]

Dana Puopolo wrote:
"Rick Levy bought most of Cambridge Crystals equipment, and yes he still
does freq measurements. He can pick stuff up from all over."

A handful of monitoring services are still in operation, such as Burt
Weiner's on the West Coast, ours near Boston, and a few others in
between.  Not much need for transfer oscillators anymore, thanks to
synthesizers that can be locked to a Loran-C or WWVB-referenced rubidium
oscillator to facilitate making measurements more simply and to more
significant figures.  In addition to frequency measurements, present-day
labs generally perform many other services, some of them probably undreamt
of a few decades ago.

Clarence Cheney and his successors operated Cambridge Crystals for 45 years,
up until 1981.  In those days the bands were less crowded, and many stations
left the air at least one night a week (usually Sun.-Mon).  That all changed
long ago.  Now "IBUZ" is already making reception more difficult on many
channels, and the situation is sure to worsen.

In the absence of interference, it is kind of amazing how far unmodulated
signals, even on UHF, can reach around the curve of the earth well enough
for their frequencies to be measured.  There are good days & bad days for
propagation, but (with experience and good equipment) it really doesn't take
much signal strength to produce an audible or visible beat note.  For FM
(including TV aural) the key is dead air, and even that is harder to come by
in this age of tight boards, with musical beds under so many spoken
segments.

Rick Levy
Broadcast Signal Lab, LLP
Cambridge, Mass.