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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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