Message-ID: <16911.200006011245@gemini>
From: "James Moritz" <j.r.moritz@herts.ac.uk>
Organization: University of Hertfordshire
To: rsgb_lf_group@blacksheep.org
Date: Thu, 1 Jun 2000 13:52:22 +0000
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Subject: LF: QRSS vs. BPSK, etc.
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Dear LF Group,
	I'm sure that modes such as BPSK have considerable 
technical advantages compared to the slow CW modes. But as in 
most areas of engineering, technical excellence is not the only 
factor.

The advantages of QRSS include the following:

- It is very easy to modify an existing CW station for QRSS 
operation - all that is required are some simple keying circuits and 
leads, and a rather basic PC with some free software.

-QRSS is not demanding on the transmitter/receiver. The duty 
cycle is much the same as normal CW, any transmitter capable of 
on-off keying can be used, all that is required of the receiver is an 
audio output. Exceptional frequency stability is not required.

-There are no synchronisation or clock recovery issues with 
QRSS; also, the PC spectrogram display effectively 'decodes' all 
the signals present in a relatively wide bandwidth. These things 
make random QSO's straightforwards - there is no need to know 
the exact frequency a station is using, the time it will be operating, 
or even to know the exact modulation method that will be used.

In summary, slow CW may not give the very best results, or be a 
particularly satisfying intellectual challenge, but it does give rather 
good results with simple equipment.

Cheers, Jim Moritz
73 de M0BMU