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LF: Re: 500kHz

To: <[email protected]>
Subject: LF: Re: 500kHz
From: "James Moritz" <[email protected]>
Date: Tue, 24 Apr 2007 19:51:07 +0100
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Dear Andy, LF Group,
At the moment, most stations in the UK seem to find an adequate SNR so they can work each other by conventional means. I expect this will change a lot when 500kHz becomes more widely available in other countries. It looks like one of the problems to be solved in order to make good use of the band for longer distance contacts is the QSB.The period between fades seems to be a few minutes - which is awkward for CW operating, since the station you are trying to work dissapears and reappears with a period of about 1 over, with the likely results of both stations losing each other, and either trying to transmit or receive simultaneously, not knowing what the other is doing. It is also awkward for QRSS and other "slow" modes, because you will inevitably loose a fair proportion of characters due to the fades. I think for long distance contacts, there is scope for a mode like "Wolf" where a signal with a lot of redundancy is integrated over a fairly long period of time. It should be easier to implement more complicated modulation schemes thanks to the lower power requirements.
At M0BMU at the moment I am getting things ready for another series of antenna and field strength measurements, extending the experiments I did on 73k and 136k some years back. This time I hope it will be 136k, 500k and maybe 1.8MHz too, to fill in the gaps in the spectrum.The TX and antenna arangements seem to be quite reproducible and stable here now, so I am working on updating my mobile FS measurement system to include the new frequencies. It's a pity 73kHz was discontinued, as now the band is eerily quiet and free from QRM. Wonder what they wanted it for?
Cheers, Jim Moritz
73 de M0BMU
----- Original Message -----
Sent: Tuesday, April 24, 2007 1:52 PM
Subject: LF: 500kHz

I've been away from the LF scene for some time, and haven't even been reading the postings recently, so know nothing of what is going on on 0.5MHz.
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