From: "James Moritz" <j.r.moritz@herts.ac.uk>
Organization: University of Hertfordshire
To: rsgb_lf_group@blacksheep.org
Date: Fri, 29 Jun 2001 14:08:35 +0000
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Subject: LF: QRV Sunday/Tuesday, QRO/QRP on LF
Message-ID: <E15FxzM-00047f-00@gemini.herts.ac.uk>
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Dear LF group,

I am rather busy at work at the moment with deadlines to meet and 
so on, but I hope to be QRV on 136k on Sunday morning for the 
SAQ broadcast and event station. I'm not sure if I will have the 
energy to run my 73k beacon signal overnight, but I will if I can. I 
would also like to be QRV on 73kHz on Tuesday morning , but will 
probably be restricted to times before 0800utc - any good to 
anyone?

Regarding the recent discussion on the use of QRP at LF, the 
transmitter power by itself does not mean much, without 
considering the antenna too. Most of the time during my "solo" trip 
to the Puckeridge Decca station last year, I was only running a 
fraction of a watt into the big antenna there, but was able to work 
D, SM and so on without great difficulty during the daytime. 5W to 
the antenna would have been close to the 1W ERP limit. Getting 
results with both low power and a small antenna is a significant 
achievement. But feeding kilowatts into a few metres of wire will 
get you a lot of corona and not much more signal. I would agree 
that building a TX and loading coil, etc, for 1 - 200W output is not 
really more complex or expensive  than building a QRP LF station. 
Operating around the 1kW level brings a fresh set of problems...  

Using QRSS is quite a good way to extend the range of a low-
power station - the computer you are reading this on is probably 
the only additional equipment needed. I did some tests with G3XDV 
a while ago where only a few milliwatts into my (at that time) 5m 
high inverted L gave Mike decent QRSS copy about 10km away. 

Cheers, Jim Moritz
73 de M0BMU