Hello Rik, LF!
This shows great similarities to some studies and tests I did together with
GM4SLV (Shetland Islands) and GI4DPE (Derry, NI) around the same time of year
during the past years.
We called this phenomenon "early propagation". It usually started with weak
fluttery signals that grew rapidly. Peak signals were very strong considering
mid-path was still well in daylight. After a period of good "early propagation"
signals generally became very unstable and weaker, often disappeared completely
until "normal" propagation in darkness took over.
This happened almost as a rule over the path Shetland - Vaasa (1100kms), but not
Derry - Vaasa (1800kms). Derry - Vaasa came alive only after midpath darkness.
This was before the introduction of WSPR using normal CW-beaconing so absolute
signals levels are unknown. Tests were mostly conducted as "skeds" and
sometimes I ran a mp3-server with my receiver audio on the www so that the
transmitting parties could monitor their own signals almost in real-time (delay
of 5-10 seconds) while the receiving station was unattended.
Thanks for sharing your findings on this phenomenon, very interesting with more
new input.
BR
Paul-Henrik, OH1LSQ
Quoting Rik Strobbe <[email protected]>:
> Over the past days I monitored the G4JNT WSPR beacon 24/24.
> During daytime I have a weak but consistent copy of Andy's signal,
> average -24dB with ups and down of some dB.
> During nighttime the signal is -10dB on average, with the usual deep
> QSB (peaking -1dB, dips down to -20dB).
> But the most interesting observation is that in the afternoon the
> first peaks (from -24dB up to -8dB) occur as early as 15:45 UTC.
> This is almost 1 hour before sunset (16:37 UTC) and almost 1.5 hours
> before the D-layer (at mid point) goes into darkness.
>
> 73, Rik ON7YD - OR7T
>
>
>
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