Monday, December 12, 2011

Checks and Balances

My XYL is fond of reminding me that life is all about checks and balances. When it comes to amateur radio under the auroral oval that is especially true. When the high-latitude K-index is zero (as measured at the NOAA station in College, Alaska, only a few degrees south of us) propagation will generally be good. Higher than zero is not as good, and more than two is just plain bad. According to my research, there have only been 15 days this year where the high-latitude K-index was zero for the whole day. That means that for any particular event, like a contest or dxpedition, the chances of having good conditions are only 1 in 23 or about 4%, just slightly better than the odds of rolling snake eyes on a pair of dice. The rest of the time we just struggle along and do the best we can under the circumstances. More sunspots certainly help but that also increases the frequency of solar flares, coronal mass ejections, and other solar badness that rains down from space and stirs up the aurora.

I’ve been pretty lucky this past couple of years with having those long odds come in during expeditions and contests. If you’re planning an Arctic dxpedition you can at least try to increase your chances a bit by scheduling it for a period during the sun's 27-day rotational cycle with no recurring coronal holes. Coronal holes increase the solar wind and generate high K-indices. For contests and other fixed-date events though, it's all luck of the draw. I managed to hit the low K numbers for most of my island expeditions in 2010 but our trip to Tent Island in June this year was something of a washout due to the poor conditions. For many years I had fantasized about what the ARRL Sweepstakes contest would be like without aurora and this year it finally happened. The K-index was at zero for the entire duration of the contest and it was everything I always dreamt it would be. The high bands were open late, the low bands were productive, and new records were set. Only two weeks later I decided to get on during the CQ World Wide CW contest and maybe pick up some new countries for DXCC. A little bit farther south of us conditions were being reported as great although many had difficulty working stations on paths that crossed over the pole. The K-index here peaked at 4 and there was a solar radiation storm to boot. I could hear a few weak signals from the west coast of the USA but that was it.

The high Arctic certainly is an interesting place to live but it's all checks and balances when it comes to ham radio.

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