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Radio Wave Optics Works! (POTA of Organ Mountains-Desert Peaks National Monument)

 In electronics engineering classes at both Ohio State and Texas A&M I did homework problem after  homework problem working out radio wave propagation. One of the fundamental points was that radio waves are just another kind of light, and therefore behave like light. Radio waves however are not like visible light in one major way, their wavelenghth. The Rockmite operates on the 20 meter ham radio band. That means that the radio waves emitted  by the little ham radio have a wavelength of (about) 20 meters. Meanwhile, visible green light (as an example) has a wavelength of about 510 nanometers (that's 510 billionths of a meter.)

This rather huge difference in wavelengths affects how the two different kinds of 'light' interact with their worlds and—for me—produces rather dissapointing results. While we can use the same field equations for both green light and radio waves, in a lot of cases radio waves do not (apparently) behave like the green light we're used to. For example, if I shine a green light at the back of our house, the usual station location for the KD0FNR rockmite, the green light will bounce off the house and go nowhere, as visible light will do. Meanwhile, the 20 meter radio wave which is emitted behind the house about 3 feet above the floor—on a good day— will be heard in Hawaii to the West, way, way out the front of the house. Just to be clear, the math does work out, nothing's wrong here, it's just that I don't get to see radio waves behave like light waves very often...

But, sometimes I do.

My recent POTA acitvation of the Organ Mountains-Desert Peaks National Monument last week was one of those times. What did the trick? I was at the foot of very nearby very abrupt mountains, (the Organ Mountains.) When I transmitted from my first remote station site, I was a little surprised to see that a RBN spotting station in California—firmly ensonced behind the mountains to the West—had heard the Rockmite. "Oh well," I figured, "It's probably another one of those long wavelength things."

Analysis of the geographical data a few days later revealed—delightfully—that there was a very apparent reason for the propagation. A straight line from station to staion went right through Baylor Pass (I was transmitting from the vertex to the right. The straight lines to California are the two lowest lines in the upper left corner of the picture):


Mapping the path out in Google Earth produced even more spectacular looking results:


(The almost vertical blue line furthest to the left is the propagation path to the California reverse beacon network station in Stanford.)

I'll write up a lot more on this in the next few days. For people who'd like to load the kml file into Google Earth for themselves, here it is. And here's a link to a Google Earth map already loaded up with the QSO path data.


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