[CQ-Contest] Listen to what happens when a X4.0 Solar Flare hits your contest operation - P40E CQWW CW 2000

[José Nunes CT1BOH]

I had the idea for this post after reading K9LA's article "Solar Flares at
ZF2RR.
http://mysite.verizon.net/k9la/Solar_Flares_at_ZF2RR.pdf

K9LA in his article explains the impact on ZF2RR operation of Solar Flares:

"(...) Dan, N9XX, was at ZF for CQ WW CW in 2000, and he did a single band
10m low power effort as ZF2RR. Overall he did very well (he won the World
for 10m low power), but he noticed several hours with significantly reduced
rates that he suspected were tied to flare activity.
There are four periods that stand out where the rate dropped significantly –
during the 18-19 UTC period on day 1, and during the 16-17 UTC, 19-20 UTC,
and 22-23 UTC periods on day 2. The rate drop during the 18-19 UTC period on
day 1 coincides with an X1.9 flare that erupted at 1836 UTC. The rate drop
during the 16-17 UTC period on day 2 coincides with an X4.0 flare that
erupted at 1638 UTC. Those were the only two class X flares during the
contest weekend(...)"

It just happens that while operating P40E during the 2000 CQWW CW Contest, I
was recording the event. And I still remember the black-out that followed
the big X4.0 Solar Flare. I thought it would be interesting to share the
story and the audio clip of the impact of the solar flare.

First take a look at the Goes Xray Flux (5 minute data) on the 25 and 26
November 2002
http://qsl.net/ct1boh/audio/20001127_xray.PNG
I marked with an arrow the big solar X4.0 flare that occurred at 16:38 on 26
November, Sunday of the contest.

P40E was QRV on 21 Mhz (21050)
In the 40 minutes before the Solar Flare impacted P40E operation, 16:00 -
16:39, I had worked 107 QSOs at a rate of  160.5 QSOs per hour.
In the 20 minutes after the Solar Flare impacted P40E operation 16:40 -
16:59 first there was a 7 minute black-out and then I managed to work 10
QSOs at a rate of 30 QSOs per hour.

Another interesting aspect to mention is that K9LA notes in his article:

"(...)The duration of the blackout depends on the magnitude of the flare.
And since absorption is proportional to the inverse of frequency squared,
28MHz will be the least affected of our HF bands. (...)"
Note that P40E reaction right after the flare, is first to tune up and down
looking for signals, and then QSY from 15 to 10 meters, and resume activity
as the band returns to normal.

Very interesting is the surge of noise right after the Solar Flare until
almost total black-out of the bands and during the 7 minute black-out. You
will listen to a a vanishing pile-up, to a dead band, and then the recovery
of activity.

You can check P40E log here to follow audio clip from 16:36z until 17:02z
http://www.qsl.net/ct1boh/audio/flare.txt

And you can listen here to the26 minutes of audio clip here.
http://www.qsl.net/ct1boh/audio/flare.wav
Note that this was an SO2R operation so you should use headphones. You will
listen on the left ear to radio 1 (RUN radio) on 21MHZ and right ear to
radio 2 (S&P radio) on 28 Mhz before the QSY to 10.

Happy New year to all
-- 
-- 
José Nunes
CONTEST CT1BOH - http://www.qsl.net/ct1boh