This is page 2. Sporadic E propagation,
which is caused by the ionization of the ionosphere at around 90-120 km
altitude, is most common between the summer months of May and September in
the northern hemisphere, and October to March in the southern hemisphere,
during daylight. Openings can also occur at other times, day or
night. It's also possible for the muf* to rise high enough for F-layer propagation
at these frequencies, but this is much more rare. Fuller explanations for
the reasons behind these forms of propagation can be found elsewhere on
the net, and if you read nothing else, read
this document.
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2006-06-12 In each image,
the top half is French channel L3, the bottom half is European channel E2.
L3's frequency is 60.500 MHz. The L3 transmitter is on 60.500 MHz
exactly, and should be the only occupant of this frequency. It is located
at Carcassonne, in SW France, at 143° Azimuth and 940 km distance. Where is this
extra signal on L3 coming from? Carcassonne, according to TV-List, should
be the only user on 60.500 MHz. Another French channel is resident at
60.5312 MHz at Besançon/Lomont. Did this drift down? Or
could it be a rogue from channel E4 at 62.250 MHz, possibly a badly
maintained TX in Africa? The wobbly signal could indicate either a poorly
maintained transmitter, or a difficult and long propagation path, or both. An intermittent sporadic E signal also appeared on 03 June - the first day I started to monitor this frequency, off-frequency by -20 Hz from the nominal 60.500 MHz...
Any information on this signal,
or signals, gratefully received at my contact email link
(see bottom of the page), and any conclusions will be reported here.
Thanks! |
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