HIGH SPEED CW FOR METEOR - SCATTER
Contacts between 500 and 1300 miles distance can be made on 50 through 432 Mhz via reflections from ionized trails left by meteors as they travel through the ionosphere. The kinetic energy of meteors no larger than peas, and more commonly the size of grains of sand, are sufficient to ionize a column of air up to 12 miles long in the E-layer. The ionized column may persist for a few seconds to a minute or more before it dissapates. This is enough time to make very brief contacts by reflections from the ionized trails.
Radio signals in the 30 to 100 MHz range are reflected best by meteor trails, making the 50 Mhz band prime for meteor-scatter work. The early morning hours around dawn are the most productive, because the Earth's rotation sweeps up incoming meteors and contributes to their apparent velocity.
Meteor contacts ranging from a second or two to more than a minute can be made nearly any morning on 50 Mhz. Meteor-scatter contacts on 144 Mhz and higher are more difficult because reflected signal strength and duration drop sharply with increasing frequency. A meteor trail that provides 30 seconds of communication on 50 Mhz will last only 3 seconds on 144 Mhz and less than one second on 432 MHz.
Because meteors provide only fleeting moments of communication even during one of the great meteor showers, especially on 144 Mhz and above, special operating techniques are often used to increase the chances of completing a contact. That's where High Speed CW comes in to play. Example: You have a schedule with someone 1000 miles away, and all you hear are many short bursts, say, 1/2 second in duration, how much information can you pass on SSB in that amount of time? With HSCW, at say, 2400 LPM (letters per minute) or 480 WPM, in that 1/2 second burst 20 separate letters could be copied, 20 leters could consist of complete call and signal report exchange!
Are you ready to learn more about this fascinting avenue of Amateur Radio? Then visit these great links:
Drop a Note to Wes, W3SE
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