Contest Flare

This will be a short article about a short subject: dealing with solar flares in a contest. The goal is to briefly describe the effects of solar flares on contest strategy. 

When I've written before about contesting in poor conditions, I emphasized how everyone is in the same situation so it is imperative to carry on. For those unfortunate cases where the effects are not the same for everyone, you can still measure yourself against others in your geographic region. It's relative performance that matters, not the absolute value of your score.

Those articles were written when solar activity was low. Solar maxima are different because flares are more frequent. For the observant ham, it is possible to gain a competitive advantage when a flare occurs. The X-class flare on August 6 during the NAQP (North American QSO Party) illustrates the point.

A solar flare temporarily boosts the ionization level in the ionosphere. While this may seem like a good thing, it is too much of a good thing since signals that would be refracted are instead absorbed. The result is a radio blackout at HF. 

Notice in this map of the estimated effects of Saturday's flare (screenshot from SolarHam) that the intensity of the blackout depends on the solar declination (angle of the sun above the horizon). The tropics are hit harder than the polar regions and where it's midday. There is no increased absorption where it's nighttime. Signal attenuation declines with increasing frequency.

When a couple of contesters in the area expressed concern about the poor weekend propagation forecast, I joked that if there's a solar flare all they need to do is to step out of the shack for 30 minutes. That may seem an odd thing to say and perhaps my joke went astray. It is important to understand that the various solar and geomagnetic indices we follow are not all alike. Geomagnetic disturbances, proton storms and flares have unique effects. The effect of flares is more predictable than most and typically of short duration.

Most flares are brief and the HF blackout can recede in as little as 30 minutes. Less common long duration flares have similarly longer blackouts. The intensity of the flare (M or X class) determines the amount of signal absorption and frequency breadth. The X1.6 flare during the contest (the above X-ray flux graph is from the GOES web site) was of moderate length and the worst of the blackout would have lasted perhaps about an hour -- I was unable to monitor the bands so I'm going by the reports of others.

Contests don't have a timeout when there's an HF blackout! As a participant you have to decide what to do. First, however you need to know that a flare occurred. When the bands suddenly empty of stations you should suspect a flare. Check the solar and geomagnetic indices. Some are updated within minutes, and the rise in X-ray flux due to a flare is very rapid. By the time you notice the blackout it is probable that the online X-ray flux data will show the leading edge of the flare.

Let's assume that you are an observant contester and you quickly discover that a flare has occurred. What should you do? Is there a way to take advantage? The answer depends on the contest. In many cases there is nothing you can do except take a short rest so that you're in better physical condition when conditions improve. In select cases you can use the flare to your competitive advantage.

Flares do not affect propagation on the night side of the Earth. There's about a 50% chance that the flare does not directly affect you. You might only notice that you cannot work stations in the daylight hemisphere. There may be no reason to change what you're doing. You can continue to do well on the low bands, which are certainly better at night. By the time the sun rises it will be business as usual. During times of low solar flux you may be totally unaware of the flare since the high bands are dead at night, and that is where you work most of the stations located in the flare-affected half of the globe.

That was not the case during last weekend's NAQP. All of North America was effected. Even stations in the eastern fringe where sunset was approaching would have found few stations to work on either the low or high bands. Going to 10 meters where attenuation is lower was not an option for most since the prevailing conditions were poor on that band.

NAQP is a contest where single op stations are restricted to operating less than the full contest duration: 10 out of 12 hours. There are other contests like this, including CQ WPX where single ops can operate 36 out of 48 hours, or 24 out of 30 hours in ARRL Sweepstakes. The best strategy in these contests may be to take time off when the flare occurs. The sooner you recognize the HF blackout and confirm the rise of the X-ray flux, the sooner you can pull the switch.

The minimum off time is typically 30 minutes. That may be enough to escape the worst of the blackout. Stations that continue to operate will see their rate and score potential decline. They will have no choice but to take their off times when conditions have recovered. A strategic off time can improve your competitive position relative to them. Check the X-ray flux to see if the worst as over -- that does not count as assistance for unassisted operators -- since listening time counts as operating time according to the rules of most contests.

Let's look at a slightly different situation. Imagine that the flare had occurred 2 hours later. Most of eastern North America would have been in darkness and not directly affected the blackout. Stations where it is nighttime have a different strategic option available to them. 

The high bands in NAQP favour those in the western half of the continent because they are relatively few compared to the major population of the eastern seaboard and US mid-west. Their run rates can be very high on the high bands. In the east, the low bands are the most productive since that is where the bulk of contacts can be made.

It can be very smart for those in darkness to concentrate on 40 and 80 meters while the HF blackout lasts. Check 20 meters occasionally for signs of recovery from the blackout -- this is where SO2R or a separate SDR spectrum monitor can help. Less time is wasted on the unproductive high bands. Since many eastern stations operate 40 meters during daylight in NAQP and Sweepstakes there are ample stations to work, including those that may be less aware of the flare's effects. The flare can alter the relative competitiveness of eastern and western competitors.

HF blackouts due to flares lower everybody's score potential. But the objective in a contest is to score better than competitors, not to achieve the highest possible score. Strategic reaction to solar flares can improve a station's prospects. It is good to keep this in mind since solar maxima bring more and stronger flares, and they will be with us for at least the next 2 years.