David et all,
The HF critical frequency could have stayed higher than 5 mhz and/or you may
have been experiencing some sporadic E (Es) propagation.
73,
Thomas F. Giella, KN4LF
Retired Space & Atmospheric Weather Forecaster
Plant City, FL, USA
Grid Square EL87WX
Lat & Long 27 58 33.6397 N 82 09 52.4052 W
kn4lf@arrl.net
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----- Original Message -----
From: David Ackrill
To: 'a Propagation Reflector'
Sent: Wednesday, December 08, 2004 2:08 AM
Subject: [Propagation] 5MHz Night time propagation question
Whilst counting the number of 'steps' of signals heard from the UK 5MHz
beacons I noticed something unusual happening. Normally the signals drop
down into the noise after about 17:45UTC and don't normally reappear until
08:00UTC the next morning.
However, on Sunday 5th December I was still able to hear them until at least
23:00UTC. The signals were not very strong, but definitely still audible
here.
I have also noticed that about 05:00UTC one or other of the beacons suddenly
puts in a signal for one or two quarter hour monitoring periods, then drops
back. I looked at results from G4IRX, who is not far away from me, and he
seems to be recording these occasional bursts at the same time, so I don't
think it’s a burst of noise.
Can anyone suggest what propagation modes are responsible for these unusual
signals?
Thanks - Dave (G0DJA)
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