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I left my receiver running into FFTDSP4 at
Friday midnight, with the longterm monitor storage enabled (by about 1000Z on
Saturday it had accumulated a 24 meg file) The 137.0 RTTY signal was not
apparent when I went to bed at about 2330Z. It appeared on the screen at about
0015Z and was quite strong between 0100Z and 0330Z with a peak in strength at
about 0300Z. During this part of the night (well morning I suppose) there was a
steady background 'crackle' like distant storm activity. At its strongest it was
reading 20dB S/N on FFTDSP's 'measuement'. This is about the same as I see for
the strongest G stations in good conditions. There is a noticable decline to
0330Z with a marked reduction in the background noise. By 0340Z it was down to
10dB S/N and by 0400 it had totally disappeared from the screen to background
noise virtually disappeared at the same time. An interesting point was that the
signal faded into the noise for several minutes then rose out of the noise again
for about 5 minutes and then faded away all together. This reminds me of the way
I have heard the HF bands close to DX when I used to be more active up there. I
have not yet investigated the Grey-line for 10th/11th June but I suspect that
this may explain why we are not hearing the Halifax N.S. (??) station as much as
we used to earlier in the year. (just for identification purposes I make the
shift about 75-80Hz in the 2Hz resolution mode of FFTDSP)
Unfortunately I am unable to log signal strength
as only the lightning crashes move the s-meter using my passive loop. As an
indication of my sensitivity, I could see DF2PY (136.9 kHz) on my screen on Sat
morning at about 6dB S/N but I could not copy his morse. I know it was him from
the Cluster spot he put up and I think PA0LQ worked him later.
General activity seemed to start about 0515Z,
with the first qso I observed at about 0524Z.
In conclusion this observation would suggest
that the best time for Transatlantic QSOs would be about half an hour before
dawn ( I dont know whether that is the visible dawn or a sort of 'radio' dawn)
It looks like we will need some insomniacs to work the States.
I understand the AMRAD beacon is operating
now.....is it on 136.75?? as was projected.
I will try to set up some signal strength
logging, but also calibrate the sensitivity of my loop aerial.
Hope that was interesting
Cheers de Alan G3NYK
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