Aurora over Pontoon Lake Territorial Park, NT, Canada, by Roland Boisvert
CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=80074065
Aurora borealis — the Northern Lights — can be the bane of a Northern-hemisphere contester’s existence. Strong aurora can form an RF-impenetrable wall between North America (at least Western NA) and Europe over the polar path, but there’s real beauty in the air whenever they appear.
Aurora Australis are just as troublesome at the opposite end of the planet. But I am reminded by recent displays in the night sky that these aurora give us a chance to work “auroral backscatter” on 10M (28Mhz), 6M (50Mhz) or higher VHF bands. It’s a lot of fun to bounce CW or Phone signals off the nicely radio-reflective clouds of ionized particles in the upper atmosphere.
I remember hearing my first auroral flutter signals on 10M late one night in the early 1980s — phone operators were calling CQ and sounded like they were talking through bubbly water. CW signals down lower on the band were just raspy shells of their original tones, but perfectly copyable at lower speed.
I’m looking forward to seeing the aurora this winter — and hope to make a few 6M CW contacts if I happen to be near the radio on a night when they appear.
Resources
- For a good overview of aurora’s utility for ham radio communications, check VE6BPR’s Aurora page.
- Another interesting overview is Stan W1GV’s YouTube video on ham radio and the aurora.
Give it a try next time you see a tinge of green or red in the night sky.
Knowing when to look up
There’s a lot of online real-time data for anyone wanting to know what the aurora are doing. When I developed the Orca DX and Contest Club propagation dashboard (shown on left), I turned to several data sources — pulling in the real-time auroral energy level to calculate an auroral power index (from 0 to 10).
If the auroral index is above 5, you might have visible aurora — if you are far enough north. When the fat part of the auroral “doughnut” is on your side of the Earth, and there’s a strong aurora, you might even see it from latitudes further south.
In the graphic dashboard, the three-hour K-index from Boulder, Colorado, and the running A-index (an average of the most recent eight K-indices adjusted to an equivalent three-hourly range) as well as solar flux are all combined to estimate expected conditions on the HF amateur radio bands, from 80M to 10M.
We also get a thumbnail image of the aurora borealis from the Space Weather Prediction Centre’s Ovation Prime model (a 30-minute prediction of aurora power), overlaid with the actual power level in gigawatts and calculated auroral index, as well as current solar wind speed and proton density.
They’re all very useful in getting a sense of how the HF bands are affected by space weather and geomagnetic conditions. And for knowing when visible aurora may be in the sky.
Through the lens
If you’re not into aurora propagation, there’s not much else to do but gaze in wonder at the workings of Mother Nature at her awesome finest. And while you’re looking up, you might consider taking a photo or two.
A useful tutorial for taking photos of aurora can be found on the NightSkyPix website. It provides what the author calls “the ultimate guide” to photographing the Northern Lights. Step-by-step instructions cover how to plan your photos, the equipment you’ll need, and tips for using that camera gear.
Whether you turn your camera or your yagi antenna north to the undulating lights in the sky, the phenomenon is a treat to observe.
