Message-ID: <1061.200101221717@gemini>
From: "James Moritz" <j.r.moritz@herts.ac.uk>
Organization: University of Hertfordshire
To: rsgb_lf_group@blacksheep.org
Date: Mon, 22 Jan 2001 17:21:15 +0000
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Subject: Re: LF: Re:VA3LK Log / More Tests
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Dear LF Group,

Alberto wrote:
> 
> Just a remark. If you want to dig deep into the noise, you must use
> resolutions of 5 or 10 milli Hertz. At these resolutions the span covered
> by a spectrogram is at maximum a couple of Hertz, so the 10 or 20 Hz
> spread would mean that the biggest part of the stations will be outside
> the screen.
> 
> 73   Alberto   I2PHD

Of course, it's a question of degree - if 40milliHz does not produce 
a signal, you could always try a narrower resolution. It does not 
really matter if the dots merge together if the purpose is only to 
identify a signal is present.To facilitate this, the signal I intend to 
use will have about 5 90s dashes and spaces, followed by a 
"missing" dash. Hopefully, this will make it a bit more distinctive, 
and if viewed at higher resolution, the dashes will merge to 
produce one long dash and a shorter space. I think this should be 
easy to set up using ON7YD's QRS keyer software in beacon 
mode, which will also do normal CW ID's

How narrow a frequency range we can use depends on how 
accurately the TX frequency can be set - my synthesiser does 
0.1Hz steps, and if everybody had the same, quite a few people 
could fit into 2Hz bandwidth. But whether this can be done depends 
on the equipment at the individual stations involved.

Since Larry's signal is visible with quite good SNR at times in 
42mHz resolution, and VE1ZJ has seen several signals with 0.3Hz 
resolution, I think 42mHz resolution might do the job. If it does not, 
it will certainly take a major re-think to achieve a QSO!

Cheers, Jim Moritz
73 de M0BMU