Message-ID: <387D4110.D8B52A65@netscapeonline.co.uk>
Date: Wed, 12 Jan 2000 19:05:52 -0800
From: "g3kev" <g3kev@netscapeonline.co.uk>
Organization: Netscape Online member
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: CFH (again!)
References: <E128KhA-0004Rh-00@mserv1a.u-net.net>
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No Windup. Its a reality if you need to use LMCW and Small Loop Antennas and
Lemonade bottles for coil formers for local qso's its  SYMPATHY you need.

Mike Dennison wrote:

> G3YMC wrote:
> > Mal mentions the problem of QRM from CFH - in case we hadn't noticed!  I
> > suggest that the Rugby transmitter on 73.4, which has more or less put an
> > end to realistic QSOs on that band, is similar both in function, purpose
> > and power to CFH.  The noise sidebands we get from GBR are probably what a
> > listener in VE1 would hear on 136!  If QSOs on 73 are limited to 11km on
> > 73kHz when Rugby is on (congratulations Jim!) we are going to find it a
> > bit hard going to work VE on 136!!
>
> I strongly believe that the noise on the Rugby 73.4kHz transmssion
> is not merely a function of its strength. Most of us (outside the
> Midlands) had no trouble having QSOs on most of the band until
> about Spring 99. I could get 9+50dB on the Rugby signal and S3
> noise floor only a couple of hundred of Hertz away, but now the
> noise is over S9.
>
> This is either accidental - noisy oscillator, or (most likely) deliberate -
>  spread spectrum or clever data mode.
>
> The effect was first noticed by Roger, G2AJV, who spent hours
> trying to fix what he thought was a fault on his antenna when he
> could neither hear nor work people who used to be good signals.
> Dave, G3YMC, himself reported being puzzled not to hear signals
> that were prevously good. Later, I tried to work G3YXM for a second
> time and we were both surprised not to hear each other. The noise
> crept up on us as the band was used for amateur contacts only
> once every few months.
>
> It is possible that CFH has some noise sidebands, but please don't
> assume that the present Rugby signal is typical of LF commercials.
>
> At the risk of winding Mal up, the only really useful way to make
> QSOs on 73 these days is QRSs. This was used by myself and
> G3LDO to work GD0MRF at 400km+.
>
> Mike, G3XDV (IO91VT)
> http://www.dennison.demon.co.uk/activity.htm