Thanks Kelvin. An interesting article.
Another factor re Aberdeen Offshore Radar 134.1 MHz occurs to me, viz some years
before the introduction of 8.33 KHz channel spacings, Aberdeen had already
introduced
rebro for offshore helicopter communication purposes and thus three
additional remote transmitters were placed on offshore platforms over 100 miles
apart. This also involved telephone links to the remote transmitters and
synchronisation
problems were challenging.
>From what I think I was told, the 25 KHz band segment assigned to 134.1 MHz was
subdivided into 4 of about 6 KHz each (I guess) and so the transmissions had
very narrow bandwidth but the receivers remained capable of the full 25 KHz.
At least this is what I vaguely recall from my days of flying helicopters to
North
Sea destinations. There were "black holes" in the coverage offshore.
I wonder if the difference between 8.33 KHz bandwidth of my aircraft radio and
the presumed 6.25 KHz of the rebro system causes some "mismatching" effects,
when
my radio is erroneously selected to channel 134.105? Any polite suggestions
welcome!
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