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Hi All,
Loran-A, post-war, was centred on 1950 and 1850
kHz. 1950 was almost entirely North Atlantic, 1850 Pacific and some American. If
you heard 1850 in the UK it was genuine DX.
All Atlantic were switched off in 1980 plus or
minus a bit, but the Japanese kept some going on 1850 until only a few years
ago. They could be heard here in UK most winter nights.
Hifix and Hyperfix occupied numerous
channels from 1650 to 2300 kHz, but was a very narrow-band system
unlike Loran which was pulses. All now closed - the dreaded GPS has taken
over.
The others on 133 and 144 are indeed Datatrak, a
British vehicle tracking system run by Securicor but also used in some countries
in Europe. A very narrow-band system
invented by a bunch of engineers who left
Decca when it was bought up by Racal in the 1980's.
If you're really interested in old radio
navaids read my just-published book "Air Navigation - from Balloons to
Concorde" (ISBN 1-903953-90-1, Woodfield Press, £25) in which there
are whole chapters on them. Yes, it's a plug (also explains why I've done very
little on the ham bands for the last few years!).
Walter G3JKV.
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