[Hallicrafters] VHF DX

[Mike Everette]

I have seen and heard accounts of events back in the
late 1870s when the NC Highway Patrol's main station
receivers in the 42 MHz band were regularly blanketed
by strong signals which turned out to be West German
TV video.

Also atthat time, I am told, there was also a lot of
Spanish-speaking stuff coming in from the Caribbean
and especially Central America, and this continued
into the early 80s.  Some very exciting, frantic
Spanish-language police chases could be heard,
complete with screaming sirens and occasional gunfire.
 Sort of a cross between "Gang Busters" and "Speedy
Gonzales."

The system switched over to tone-coded squelch (CTCSS,
PL, Channel Guard etc) to try and eliminate this; but
tone doesn't protect the receiver from "capture" if
the interfering signal is in excess of 60 to 80
microvolts!  Limiter-current readings taken on
receivers being fed with signals from calibrated
signal generators confirmed that the QRM was at least
that strong, or stronger, at times.  Of course, some
of the antennas were atop 200 to 300 foot towers.

I have experienced band openings on 39.1 MHz, which
almost every city police department and sheriff's
office in eastern NC used to use.  In some cases, a
car within a quarter mile of the base station, and in
direct line of sight of the antenna, would have to get
a relay through a dispatcher in Fargo, North Dakota. 
Some of these openings would last for 18 to 24 hours
or even longer.

73

Mike
WA4DLF



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