----- Original Message -----
From: "Marek SQ5BPM" <[email protected]>
To: <[email protected]>
Sent: 17 January 2005 14:26
Subject: LF: HF75PZK
I don't know whether conditions will allow some nice QSOs on LF as well,
as there were major CMEs last days. BTW - is there a reason that condx
on LF are in great shape just before the CME happens? I saw the message
about reception of VO1NA in QRSS3 - this is not the first time that
exceptionally good conditions happen only a few hours before the hit.
Hi Marek. not really..... except that it is usually the best conditions
since the last Geomagnetic storm. The best conditions are not in dead quiet
geomag conditions. After a long quiet spell a Kp=4 event brought good
conditions for several nights. When there is some activity there is a
chance ( we sometime laught about the "14 day" rule....try 14 days after a
major storm ) that if there is some multipath and the ionosphere is
resonating slowly up and down after the last shock front, good conditions
will occur on some paths. Joe has an almost all water path to the UK and
Europe so he is not so affected by absorbing conditions. He is probably one
skip closer than the East Coast US stations. There is nothing before a CME
arrival to affect the ionosphere, but certainly through the more active
years I have seen that sometimes that the best night in a given period has
been just before a storm. But at that time the Dst is still dropping and the
quantity of absorbing precipitated electrons leaked into the D-layer from
the ring current is probably dropping. So it is the minimum absorbtion night
for that period. (I think !!) The peak signal levels measured during
favourable multipath can be 6 to 10dB above those in long flat storm free
periods. The problem is we need at least 30 minutes to get an "over" through
on QRSS.
We will look forward to hearing (?) or seeing your signals again.
Regards de Alan G3NYK
| 