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LF: Re: LF activity

To: [email protected]
Subject: LF: Re: LF activity
From: "James Moritz" <[email protected]>
Date: Wed, 23 May 2001 15:38:34 +0000
Organization: University of Hertfordshire
Reply-to: [email protected]
Sender: <[email protected]>
Dear LF Group,

I have no experience of contest operating, so I will not offer judgement as to whether I think it is a good idea or not. However, I am not convinced by the argument that the band is too narrow. At the moment, the band seems to be used very inefficiently - for example, although the "CW" band segment extends from 136.0 - 137.4, it is rare to hear any CW signals outside about 136.4 - 136.9, even during the busy periods. Some of this is due to local QRM, but clearly there is plenty of room for more operators on the band simultaneously.

The equipment demands for casual LF reception aren't really that demanding - with high noise levels and low ERPs on LF, the dynamic range and filter shape factor of fairly modern HF rigs that most amateurs seem to have are not likely to be seriously challenged by amateur signals, beacon or otherwise. But LF receive is usually an afterthought on an HF rig, also 136kHz is more than a factor of 10 lower in frequency, and more than a factor of 10 narrower in bandwidth than any HF band, so different techniques must be applied for good results. Using an HF RX with an SSB filter, poor LF sensitivity and a random, untuned bit of wire plugged into the antenna socket just isn't going to work very well, and even with the best will in the world, reception of a few local stations is all that can be expected. Once someone has become interested, it has to be up to them to improve their station, just as for any other band or mode. Would anyone expect to make EME contacts with a 2m FM handheld?

The main thing that will encourage more people to listen on the band is more signals - any recognisable signal has to be better than none. Permanent beacons probably use up too much bandwidth and have licensing implications, but why not have more temporary beacon signals for a few hours when the band is quiet, as Dick suggests? This could be done in any mode or band segment. Obviously, a sensible choice of frequency and time would be required to avoid problems, but there seems to be plenty of room, as noted above.

The other possibility that was raised is to have more cross-band activity - since it is much easier to get set up for receive on LF than to transmit, this would give an easy route for people to get involved before they have a full tranceive capability on LF. Again, most modern HF rigs with LF receive capability seem to have multiple VFOs, memories etc, so this should be quite easy for a lot of people to try. Probably the most important thing here is publicity.

Cheers, Jim Moritz
73 de M0BMU




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