From Dave G3YMC
Mal yesterday and today gave a very detailed signal report on CFH during
daylight hours, and his reports, in particular on hearing it at 1530 today,
agree largely with the reception here. However we need to interpolate his
figure backwards in time. During the night (midnight onwards) till 0800 CFH
is some 10dB stronger than the signal at 0830 (s9+10 on my meter, probably
s9 on Mal's). This is the time of main propogation, where the signal is
enormous, and is the time when any amateur QSO would take place. This
follows closely the state of the D layer over the path and is a true night
time effect.
The much weaker signals copied during the day (it was pretty weak this
afternoon) are characteristic of the effects found on similar paths on 160 -
VE1 has also been heard on that band in the late afternoon, and even I
believe at midday. This is probably some form of scatter propogation via
the arctic and polar regions which are in permanent night. I suppose with
the power of CFH it could also be its signal punching through the D layer
(which may be thinner in winter). Such propogation is only seen at the
middle of the winter season.
The Greek RTTY follows a similar pattern, only because it is nearer the
daytime signal is rather stronger. Note that this signal becomes strong
before dusk, but goes down before our dawn, following the night path between
the UK and SV.
Mal mentions the problem of QRM from CFH - in case we hadn't noticed! I
suggest that the Rugby transmitter on 73.4, which has more or less put an
end to realistic QSOs on that band, is similar both in function, purpose and
power to CFH. The noise sidebands we get from GBR are probably what a
listener in VE1 would hear on 136! If QSOs on 73 are limited to 11km on
73kHz when Rugby is on (congratulations Jim!) we are going to find it a bit
hard going to work VE on 136!!
73s Dave G3YMC
[email protected]
http://ourworld.compuserve.com/homepages/sergeantd
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