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Prepare for the Perseids!

08/05/2009

On the night of August 11 and well into the next day, Earth will make its annual passage through the bulk of the debris shed by a comet known as Swift-Tuttle. Much of the debris is composed of dust-sized grains, but when these fragments come plunging into our atmosphere they can create a dazzling meteor display. Not only are the meteors fascinating to watch, they also leave short-lived streams of ionized gas in their wake. As hams have known for years, these meteor trails are excellent reflectors of radio waves.

The Swift-Tuttle meteor showers are known as the Perseids because they appear to come from a point in the sky that lies within the constellation Perseus. This year's shower is forecast to be especially active because we're about to pass through a somewhat thicker filament of dust that boiled off Swift-Tuttle in 1862.

If you own a 6 or 2 meter SSB/CW transceiver, you can get in on the action, bouncing your signals off Perseid meteor trails and making quick meteor scatter contacts over hundreds of miles, and possibly even as much as 1200 miles. Meteor scatter operation is particularly easy on 6 meters where 100 W and an omnidirectional antenna will do the job. On 2 meters a directional antenna (such as a multielement Yagi) usually yields better results.

Some meteor scatter operators prefer to use SSB, making rapid exchanges of signal reports and grid squares. In recent years digital meteor scatter has been increasing in popularity. With the free sound-card-based WSJT software suite by Joe Taylor, K1JT, it is possible to make digital meteor scatter contacts almost any time of the day or night, not just during annual showers. Most WSJT scatter operators use a mode known as FSK441 and center their activities on calling frequencies at 50.260 and 144.140 MHz. They also announce their availability by using Web sites just as N0UK's Ping Jockey Central.

So turn on your radio late Tuesday night and start listening. As the shower intensifies, you'll begin hearing bursts of signals. That's the time to grab the microphone (or keyboard) and get on the air!



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