From: "Mike Dennison" <mike.dennison@rsgb.org.uk>
Organization: Radio Society of Great Britain
To: rsgb_lf_group@blacksheep.org
Date: Tue, 5 Oct 1999 15:18:13 +0100
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Subject: LF: 73kHz
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A couple of tests on 73kHz have flagged up a possible problem on 
ther band.

I transmitted for some of the evening of Monday 4 Oct on 71.91kHz 
but was not audible with G3YXM. I also listened for Dave's signals 
but could not hear him either. This is despite us having a QSO last 
winter and my antenna system being much better since then.

My sked with G3LDO also failed both ways on Tuesday morning. 
previously I was able to copy Peter consistently at 549. Although he 
had never heard me, my 136kHz signal has gone up 2 s-points 
since our last try on 73 so I had a reasonable assumption that it 
would be easy.

A possible answer is that the Rugby signal on 73.0kHz appears to 
have bigger noise sidebands and is raising the noise floor at 1kHz 
or so out. A quick test with a directional antenna reduced the noie 
floor but I still could not hear Peter.

We are carrying out another test tomorrow morning (6 Oct) between 
0700 and 0745UTC, and I will be transmitting a beacon this evening.

Has anyone else noticed increased white noise on 73 recently? 
Since my activity on the band is very sporadic and my antenna 
changes in between it is difficult to do a proper comparison myself.


Mike, G3XDV (IO91VT)
http://www.dennison.demon.co.uk/activity.htm