Some people may not realize that an airplane seat may be the perfect place to get your ‘DXing fix.’
While at 30,000 feet, FM stations can be picked up with an ordinary FM radio up to 300 miles away. Since the airplane travels at speeds up to 500 mph, the selection of FM signals coming in is always changing. Quite frankly, airplane DXing can mirror a very intense Sporadic E opening, often with multiple stations fighting for control of the frequency.
But what many airbound DXers may not realize is that the location of your seat may be a determining factor in what your radio actually picks up.
Although I’ve used various radios, including a built-in FM receiver in various walkmans over the years, I have found that the Insignia NS-HD01 is perfect for use on an airplane. It is small, inconspicuous and looks like an average mp3 player to other passengers.
I decided to do a year-long experiment. My hypothesis was that the side of the plane you sat on determines the selection of stations you receive. In other words, if you sat in a window seat on the right side of the plane, most signals you would get would be from the general direction that your window faces. At the same time, I also believed that another DXer sitting on the opposing-side window seat would get a totally different log of signals from their side of the plane.
Unfortunately, I have not had the pleasure of traveling with another DXer, so I had to do this test solo.
I first tested my hypothesis in April 2013, with a flight from Washington, DC to Las Vegas, NV. The trip had a connecting flight in Chicago, IL.
Click to enlarge.
The chart above depicts all radio stations received on the flights from Washington, DC to Las Vegas, NV. The red flight was my first Washington, DC to Chicago, IL flight, while the blue line was the connecting Chicago, IL to Las Vegas, NV flight. I sat on the right side of the plane in a window seat. The plotted points are towns and cities that I received radio stations from. Since my window faced north, the majority of received signals were from that general direction.
The chart above shows what I received on my return flights from Las Vegas to Washington (with a connecting flight in Denver, CO). Again, I sat in a right-side window seat. Facing south, the majority of FM signals received were from the south.
In August 2014, I did the complete reverse to further test my hypothesis that the location of an airplane seat dictated the direction of FM signals received during a flight from Baltimore, MD to Los Angeles, CA. For all 2014 flights, I sat on the left side of the plane in a window seat.
The chart above shows what was picked up in the Baltimore, MD to Los Angeles, CA flight. Surprisingly, although most signals were from my south-facing window, many signals popped in from the other (northern) direction.
The chart above shows my 2014 return flights from Los Angeles, CA to Washington, DC. In these flights, I saw the return of the “direction of window = direction of FM signals received” phenomenon.
Interestingly enough, the 2013 and 2014 flights from Denver, CO to Washington, DC were more-or-less identical in terms of airports utilized and the flight path. This afforded me an even more interesting opportunity to see how where you sit on an airplane determines what FM signals are received on the same flight without having another person simultaneously DX across the plane. As noted, the right-side (south-facing) 2013 flight had a largely different selection of FM stations received, in terms of geographic area, compared to the 2014 flight where I sat in the left-side (north-facing direction) of the flight.
Important to note: I flew the same airline in all aforementioned flights. In 2013, electronic devices were prohibited from use during landing and takeoff, while in 2014 the airline allowed gate-to-gate use of handheld electronics. This is largely visible in the Denver flight chart above since the red plots from the 2013 flight are only for the middle portion of the flight, while the blue plots are from originating city to destination city.
My hypothesis was proven right, with some caveats. Seat location is defintiely a major determinant of what your radio can pick up and it should be used as a rule of thumb when selecting airline seats with the hopes of DXing in mind. As noted in all flights above save for the Baltimore, MD to Los Angeles, CA flight, most signals received were in the general direction that my window faced. However, there were several signals received through the airplane fuselage in the opposite direction.
It is also worthy to note that the flight receptions from Washington, DC to Las Vegas, NV in 2013 were done with a Sony cassette walkman radio, while the Las Vegas to Washington, DC flights in 2013, as well as all 2014 flight receptions were done with the Insignia NS-HD01. Perhaps this also proves the cassette walkman picks up less signals but at further distances, while the Insignia picks up more signals but at closer distances. I’m not sure which is more favorable from a DXing standpoint.
Knowing how the airplane window direction affects the variety of signals received can come in handy for DXers, especially when flying near bodies of water. For example, a flight from New York, NY to Miami, FL will likely hug the East Coast. On the Miami-bound flight, I’d argue that it would be less likely to get a lot of FM signals when sitting on the left side of the plane (facing the ocean). This is not to say that nothing would be received if on the left side. Likely, most of what a DXer would receive are coastal radio stations, such as those from Myrtle Beach, Savannah, Jacksonville, etc. The same proves true in reverse for the return Miami to New York flight — DXers would likely have to sit on the left side of the plane to achieve favorable DXing reception for the entire length of the plane. I’ll test this hypothesis on a future flight that hugs a coastline.
Please note that I sat in the window seat in all of my aforementioned flights. I did not test how sitting in the middle or aisle seats of a plane affected reception due to the ongoing initial test as described above. Given how the airplane fuselage apparently attenuates signals when seated on one side of the plane, I predict that a DXer seated in an aisle seat would likely receive signals, more or less, from directly under the plane (with signals from both directions of the windows on each side coming in on occasion). This will also be tested on a future flight.
I’ve sat in various parts of an airplane during a flight (front, back, center, overlooking the wing/turbine engines) and I have found this has no bearing intereference-wise for receiving FM signals on a plane.
Another aspect to consider is what would a DXer receive on a flight that is predominately over an ocean (i.e. New York, NY to London). Although I have never flown internationally, I predict that the FM band would be devoid of signals for much of the flight over the ocean.
Before flying, it is wise to go to an airplane tracking website, such as FlightAware.com, and research potential flight paths for future flights to decide on which side of the airplane to sit on for maximum DX reception.
There’s no guarantee you would receive preferred signals while in flight. For example, let’s say a Miami, FL to New York, NY flight is likely to pass over Savannah, GA. Although you may fly right over Savannah, other signals from neighboring areas could easily block all Savannah signals for the short time (~20 minutes or so) that Savannah FM signals could be received. A perfect example of this was in my 2014 Denver to Washington flight. I was close to Chicago for a large portion of the flight, but I didn’t get any of the city’s major FM signals.
Overall, I think airplane DXing is fun because it has the ‘unknown factor’ that a good Sporadic E opening has: You’ll never know what your radio would pick up.
Airplane stock images courtesy stock.xchng. Plotted maps courtesy Google Maps and multiplottr.com