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Surfin’: Going Tropo


By Stan Horzepa, WA1LOU
Contributing Editor

This week, your Surfin’ conductor considers the reasons why his car radio is acting funny.

My normal Saturday morning mission began as usual: Driving my Subaru with my wife on board to go buy groceries. As we headed north over the top of South Mountain, I tuned the car radio to 102.1 MHz and expected to hear the vintage rock sounds of WAQY.

At that point in our journey, we are literally about 30 miles line of sight of the WAQY transmitter, but instead of hearing WAQY loud and clear, its signal was muddled with two or three other signals on 102.1 MHz.

“Band opening,” I said to my wife.

“What?” she replied.

“Never mind,” said I and we continued on our mission to shop for provisions in ESPN-ville.

By the time we returned home, the band was back to normal and what I assumed was tropospheric propagation was gone with the wind.

Such is my typical tropo experience on a summer day: The tropo is cooking by the time I drag myself out of bed and disappears as the morning progresses.

On good days, I check the APRS map first thing in the morning and see stations on Cape Cod. On real good days, stations deep into Pennsylvania and south to the Carolinas show up, but they all disappear by high noon.

I always felt that APRS was a great bellwether for enhanced 2 meter propagation. You have thousands of ham radio stations all over the world regularly transmitting their exact locations, typically on the same frequency (144.39 MHz in the USA). Monitor that frequency, and when the DX APRS starts rolling in, it is a good time to move over to the weak signal portion of the band and start calling “CQ.”

The aprs.mountainlake website automated the process. It collects recent APRS information, determines which stations are receiving DX APRS transmissions and displays that information as a footprint on a Google map that can display the whole world or your whole neighborhood.

Back to tropo, meteorologist William Hepburn provides six-day forecasts of worldwide tropospheric propagation conditions. Hepburn’s website also describes the phenomena. has a tutorial on tropospheric propagation and Wikipedia does a good job tackling the topic and includes a short list of “notable” tropo DX events.

Until next time, may the inversions be with you -- and keep on surfin’!

Editor’s note: Stan Horzepa, WA1LOU, seeks the unusual in radio. To contact Stan, send e-mail or add comments to the WA1LOU blog.



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