Message-ID: <29778.200012071319@gemini>
From: "James Moritz" <j.r.moritz@herts.ac.uk>
Organization: University of Hertfordshire
To: rsgb_lf_group@blacksheep.org
Date: Thu, 7 Dec 2000 13:22:40 +0000
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Subject: LF: VE2IQ's .WAV file /73kHz
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Dear LF Group,

Was interested to see Bill's report of the reception of LEK using 
slow CW. I played the .WAV file back using spectrogram - I have to 
admit I could not make out the CW by ear (it's rather a short 
sample), but the signal is clear enough on the spectrogram trace - 
it looks like 3s dots, once the compression factor of 40 is taken 
into account.

Something else that is interesting is the noise on the display. If you 
look at a night-time spectrogram at my QTH, it is like a crazy tartan 
pattern, with vertical streaks every few seconds due to QRN, and 
horizontal ones every few Hz due to various signals and Loran. On 
VE2IQ's sample, there is nothing in the bandwidth apart from LEK 
and what appears to be random noise (although I suppose this 
would only correspond to a bandwidth of about 10Hz in real time) - 
this is what it sounds like too. Is this an effect of the 'Crunch' 
compression process, or does it mean that Bill's QTH is very quiet, 
or mine is very noisy?

On 73kHz, The Rugby TX seems to have spent most of the last two 
days transmitting a pair of carriers spaced 85Hz, centered on 
73.250kHz - perhaps they have problems again. On Tuesday, they 
shut down on schedule, between about 0800 and 1700. I Hope to 
be QRV friday evening, and will also try to be on Saturday morning -
 earlier in the year, the mornings seemed to be better for DX 
reception on 73k. This week I will be listening for cross band 
contacts too.

Cheers, Jim Moritz
73 de M0BMU