Impact of solar disturbances - cqww cw 2000 p40e

Some time ago I came across K9LA article Solar Flares at ZF2RR. 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. (...) . 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. I vividly remmember the black-out that followed the big X4.0 Solar Flare. You can now enjoy the experience:

  • First please take a look at the Goes Xray Flux (5 minute data) on the 25th and 26th November 2000
  • Second listen the audio clip (right click and save the audio file to your PC)
  • Finally follow the audio clip with the Contest Log below the graph

Below is a plot of the Goes Xray Flux (5 minute date) during the 25 and 26th and 27 November, Saturday and Sunday of the Contest. As you can see during the first two days (the Saturday and Sunday of the contest), there were several Solar Flares. I marked with an arrow the big X4.0 Solar Flare that occured at 16:38 on 26 November, the Sunday of the contest.



What as the impact of such incredible Solar Flare activity in P40E CQWW operation?

In the 40 minutes before the Solar Flare, 16:00 - 16:39z, I worked 107 stations at a rate of 160.5 QSOs per hour
In the 20 minutes after the Solar Flare, 16:40 - 16:59z, I worked 10 stations at a rate of 30 QSOs per hour

Check below P40E's log corresponding to the audio clip

QSO# Band Date Hour Freq. Call
5606 15CW 26-Nov-00 16:36 21050 IT9VDQ
5607 15CW 26-Nov-00 16:36 21050 UX7UN
5608 15CW 26-Nov-00 16:36 21050 G3VQO
5609 15CW 26-Nov-00 16:38 21050 K7MI
5610 15CW 26-Nov-00 16:38 21050 K9LJN
5611 15CW 26-Nov-00 16:38 21050 W8KXO
5612 15CW 26-Nov-00 16:38 21050 W3KGL
5613 15CW 26-Nov-00 16:39 21050 W3ZJ
5614 15CW 26-Nov-00 16:39 21050 K3KO
5615 15CW 26-Nov-00 16:39 21050 N4TO
5616 15CW 26-Nov-00 16:39 21050 RK3AD
5617 15CW 26-Nov-00 16:40 21050 W9OL

<<<<< 7 minute Black - out>>>>>>>>>

5618 10CW 26-Nov-00 16:48 28050 W4FDA
5619 10CW 26-Nov-00 16:50 28050 K4GKD
5620 10CW 26-Nov-00 16:51 28050 K9HUY
5621 10CW 26-Nov-00 16:53 28050 N2AN
5622 10CW 26-Nov-00 16:54 28050 AE4RO
5623 10CW 26-Nov-00 16:55 28050 N4TO
5624 10CW 26-Nov-00 16:56 28050 K9LJN
5625 10CW 26-Nov-00 16:57 28050 W9WUU
5626 10CW 26-Nov-00 16:58 28050 K4ZT
5627 10CW 26-Nov-00 17:00 28030 GM7V
5628 10CW 26-Nov-00 17:00 28030 KS4YX
5629 10CW 26-Nov-00 17:02 28030 DL0PAF
5630 10CW 26-Nov-00 17:02 28030 K5ZD

Comment from other contesters also hit by the X4.0 Solar Flare:


  • Roger G3SXW:
We remember it well, multi-multi at 9G5AA. What I learned was that the highest bands were least affected: they (20, 15, 10m) all died at the same moment but started recovering on 10m first, then 15m, then 20m. Total fade-out (I didn't measure it) was probably 2-3 minutes longer on 15 than on 10m, and again 2-3 minutes longer on 20 than on 15m. There was only five minutes or so when we all just sat staring at each other in shock!

  • Dan N9NX:
Your recording is an amazing find, and brings back a vivid recollection of the 2000 CQ WW contest as ZF2RR @ ZF1A. At the time in 2000, I was sitting side by side with the estimable K6AM; John was operating 15m SOHP (as ZF2AM). We both looked at each other with that look of "what the hell just happened?" - didn't take long to figure it out however! I do recall that we experienced the outage and recovery at slightly different times. K9LA (as ZF2LA) was operating 40m SOLP along with us, so he would not have been on-air at the time. I pulled up the log that was the basis for K9LA's article. The ZF2RR log tells a very familiar story. One cool thing - when my rate picks up, I also snagged a QSO with K5ZD!

QSO: 28000 CW 2000-11-26 1635 ZF2RR 599 8 SP1PLA 599 15
QSO: 28000 CW 2000-11-26 1635 ZF2RR 599 8 N7YT 599 03
QSO: 28000 CW 2000-11-26 1635 ZF2RR 599 8 OZ5DX 599 14
QSO: 28000 CW 2000-11-26 1636 ZF2RR 599 8 F5MOY 599 14
QSO: 28000 CW 2000-11-26 1637 ZF2RR 599 8 K5KW 599 04
QSO: 28000 CW 2000-11-26 1637 ZF2RR 599 8 IT9GAC 599 15
QSO: 28000 CW 2000-11-26 1638 ZF2RR 599 8 DL1RNT 599 14
QSO: 28000 CW 2000-11-26 1639 ZF2RR 599 8 DF6QB 599 14
QSO: 28000 CW 2000-11-26 1639 ZF2RR 599 8 KG8WK 599 04
QSO: 28000 CW 2000-11-26 1639 ZF2RR 599 8 DK5PR 599 14
QSO: 28000 CW 2000-11-26 1640 ZF2RR 599 8 W1DAD 599 05
QSO: 28000 CW 2000-11-26 1640 ZF2RR 599 8 AD4YM 599 05
QSO: 28000 CW 2000-11-26 1640 ZF2RR 599 8 HA1BC 599 15
QSO: 28000 CW 2000-11-26 1641 ZF2RR 599 8 W7OT 599 03
QSO: 28000 CW 2000-11-26 1642 ZF2RR 599 8 NT6R/4 599 05
QSO: 28000 CW 2000-11-26 1647 ZF2RR 599 8 KG9N 599 04
QSO: 28000 CW 2000-11-26 1651 ZF2RR 599 8 OK1VSJ 599 15
QSO: 28000 CW 2000-11-26 1657 ZF2RR 599 8 NO2R 599 05
QSO: 28000 CW 2000-11-26 1700 ZF2RR 599 8 N3NA 599 05
QSO: 28000 CW 2000-11-26 1703 ZF2RR 599 8 OK1AVY 599 15
QSO: 28000 CW 2000-11-26 1705 ZF2RR 599 8 OE5OHO 599 15
QSO: 28000 CW 2000-11-26 1708 ZF2RR 599 8 EA9LZ 599 33
QSO: 28000 CW 2000-11-26 1711 ZF2RR 599 8 N2BIM 599 05
QSO: 28000 CW 2000-11-26 1714 ZF2RR 599 8 HG1W 599 15
QSO: 28000 CW 2000-11-26 1715 ZF2RR 599 8 9A3B 599 15
QSO: 28000 CW 2000-11-26 1715 ZF2RR 599 8 K3WW 599 05
QSO: 28000 CW 2000-11-26 1716 ZF2RR 599 8 GM3POI 599 14
QSO: 28000 CW 2000-11-26 1716 ZF2RR 599 8 EI5DI 599 14
QSO: 28000 CW 2000-11-26 1717 ZF2RR 599 8 OL7R 599 15
QSO: 28000 CW 2000-11-26 1720 ZF2RR 599 8 CT3BX 599 33
QSO: 28000 CW 2000-11-26 1720 ZF2RR 599 8 K5ZD 599 05


  • Randy K5ZD:
I recall this contest and the flare as well. I was operating SOAB from my home station. The bands seemed to go dead and then slowly recover. This is difficult to process when you have already been awake for 40 something hours. With the bands broken, I began to tune around and see what I could find. I "discovered" that 10 meters seemed to be where I could find QSOs. It was weird to tune through big empty patches when the bands had been packed just moments before. My rate sheet tells some of the story:

12Z - - - 142/7 3588/622
13Z - - - 140/6 3728/628
14Z - - - 119/7 3847/635
15Z - - - 114/7 3961/642
16Z - - - 87/3 4048/645
17Z - - - 78/7 4126/652
18Z - - - 106/3 4232/655
19Z - - - 93/7 4325/662
20Z - - - 60/11 4385/673

The log snippet doesn't look that bad, until you realize how good the rate was during the first half of the 16z hour.

21048 CW 2000-11-26 1636 K5ZD 599 05 9A3GO 599 15
21048 CW 2000-11-26 1637 K5ZD 599 05 UA1ZCX 599 16
28131 CW 2000-11-26 1638 K5ZD 599 05 DK2OY 599 14
21048 CW 2000-11-26 1638 K5ZD 599 05 OK2BGK 599 15
21048 CW 2000-11-26 1639 K5ZD 599 05 DL5NO 599 14
21048 CW 2000-11-26 1639 K5ZD 599 05 DL2ANM 599 14
21048 CW 2000-11-26 1640 K5ZD 599 05 RX6AUE 599 16
21048 CW 2000-11-26 1641 K5ZD 599 05 EW5O 599 16
21048 CW 2000-11-26 1643 K5ZD 599 05 LA7MFA 599 14 <<<<<<<<<<<time to tune
28139 CW 2000-11-26 1644 K5ZD 599 05 HB2FAP 599 14
28144 CW 2000-11-26 1647 K5ZD 599 05 OK2ZC 599 15
28149 CW 2000-11-26 1647 K5ZD 599 05 IZ0AIS 599 15
28152 CW 2000-11-26 1648 K5ZD 599 05 SP6NIC 599 15
21028 CW 2000-11-26 1651 K5ZD 599 05 YL2SM 599 15
28009 CW 2000-11-26 1656 K5ZD 599 05 SN5N 599 15
28019 CW 2000-11-26 1659 K5ZD 599 05 OM3NY 599 15
28020 CW 2000-11-26 1700 K5ZD 599 05 G4ODV 599 14
28021 CW 2000-11-26 1700 K5ZD 599 05 IT9AF 599 15
28031 CW 2000-11-26 1702 K5ZD 599 05 P40E 599 9
28040 CW 2000-11-26 1705 K5ZD 599 05 GM3POI 599 14
28050 CW 2000-11-26 1708 K5ZD 599 05 OK2PKY 599 15 <<<<<<<<<<<recovery begins
28050 CW 2000-11-26 1708 K5ZD 599 05 HA8YU 599 15
28050 CW 2000-11-26 1709 K5ZD 599 05 HA0HH 599 15
28050 CW 2000-11-26 1710 K5ZD 599 05 VE3OTL 599 4

These really big contests do give us some great data points to study the impact of sudden solar disturbances.

CT1BOH - Josť Carlos Cardoso Nunes - ct1boh@gmail.com