Dear Mal, Alan, HF Group,
I have spent some time during the past couple of years listening to the
band around 500kHz - I have yet to hear any 2-way communications going on.
What I do hear is various shore stations (mainly Italian), who pop up on
500kHz, then QSY to a nearby frequency to broadcast traffic lists, weather
reports, and bulletins of shipping hazards. I guess these same broadcasts
are being tranmitted on HF - they seem to be machine generated. As Alan
suggests, there is a difference between the broadcasts being there, and
anybody actually using them. I think NAVTEX is an entirely automatic set
up, with a dedicated RX printing out the broadcasts, without any operator
being involved. The marine radio suppliers don't seem to be offering MF
transmitters - how many ships do you see with a viable MF transmitting
antenna? Even with the broadcasts, the majority of the spectrum around
500kHz never seems to have any signals in it, so it would seem there is
plenty of room for a few kHz of amateur band without causing problems. I
have heard that there is some interest in using this frequency range for
broadcasting differential GPS information, so that may be part of the
reason the powers that be are not keen on an amateur band.
In a QSO with G3XIZ yesterday, I heard that M0FMT is in the process of
getting set up on 73kHz, and hopes to be QRV in the near future - so one
worth watching out for.
Cheers, Jim Moritz
73 de M0BMU
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