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Summer FM DX: Drive-by Sporadic E

Many thanks to SWLing Post contributor, TomL, who shares the following guest post:


Summer DX – Sporadic E, FM band

“Sporadic E” DXing is a specialty of some DXers.  I have never dabbled in it being content with mediumwave or shortwave listening.  However, it was truly fun to spontaneously hear this happen while driving on the Interstate highway, Wednesday August 4 around 6pm Central Time.

To quote from an ARRL propagation article:

“As frequency increases still further, signals will eventually pass through the F1 layer to the F2 layer. Because this is the highest reflecting layer, the distance spanned by signals reflecting from it is the greatest. The maximum skip distance for the E layer is about 2000 km. For the F2 layer that increases to about 4000 km—a significant gain.”

I was listening to the local classical music station WNIU in DeKalb, IL which is a good 50 kW transmitter about 10 miles behind me near the Interstate highway.  A different station was breaking through. Eventually, I heard a familiar Christian song “You Make Me Brave” swamp the classical music. I noticed it was a remake of a song made about 10+ years earlier. The two signals fought it out and then I heard the station ID “Spirit FM” and a short humorous segment called “Attitude Adjustment”, then more music.  Finally the local classical music station won out and I thought I would look up the station ID of that contentious station later.

When I googled “90.5 Spirit FM”, it came up with a station in Tampa Bay, FL called WBVM. Cool!  Just to be sure, I went to the station web site and looked up their playlist and this confirms what I heard:

Curious about the transmitter, Radio Locator said it was a 100kW station and gave the Long/Lat coordinates.  I then went to Google Earth and mapped an approximate distance of 977 miles (1572km), give or take 10 miles:

I did not have time to get on the shortwave radio to see if the 10 meter band was busy since I had things to do.  But it is a very nice surprise to hear in my old car radio an FM station almost 1000 miles away. For one thing, Analog radio is still fun.  Secondly, things are busy this summer if you are at the right frequency and time!

Happy Listening,

TomL

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Sporadic E on the Red Planet

(Source: Inverse)

Thanks to NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) mission to Mars, you may soon never need to fiddle with the tuning dial on a car radio again.

When we listen to songs on the radio, the sound travels via radio waves that are given out by a transmitter and then received by a receiver — in the case of a car, the car’s antenna is the receiver.

Radio waves travel in the form of electromagnetic radiation from one antenna to the other. The journey, however, isn’t always perfect.

Sometimes, there is a sudden spike in the amount of hot gas in the upper layer of Earth’s atmosphere which causes interference in radio communications. If you are tuned into a favorite station, that could result in static, or for one radio station to be replaced by another.

This phenomenon, known as sporadic E layer, is difficult to study on Earth because that part of the planet’s atmosphere is hard to reach with satellites. As a result, scientists can’t predict when they will occur — leaving us to fiddle with dials.

But thanks to MAVEN, a spacecraft traveling 300 million miles away from our planet, we could finally have the solution.

MAVEN detected sporadic E layer in Mars’ upper atmosphere, and scientists are hoping to be able to use the Red Planet as an off-Earth laboratory to study the phenomenon up close. Already, the data have provided new insights into the cause of radio static, which also affects communications with aircrafts and military radars.[…]

Click here to read the full story.

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