ShortWAve.MP3

This recording was made via a "binaural" receiver of my own construction. Basically it's a short-wave receive, tuned to the 40 meter amateur radio band, and unlike most receivers, which have only a singe antenna and one detector and amplifier, this one has a separate antenna, detector, and amplifier for each ear. One antenna is vertically polarized and the other horizontally polarized, hence the perceived position of any received signal depends on the relative phase, amplitude, and frequency of the signals picked up by the two antennas. This confers a startling spatial effect, in which signals migrate back and forth across the sound stage depending on the location of the transmitter and the state of the ionosphere between transmitter and receiver.

This particular recording was made of many stations competing to contact a DX (Distance, in ham lingo) station. The DX station, located in some exotic foreign place, sends out a CQ, or a general call, and hundreds or thousands of stations who want to contact him (or her) send their call signs in hopes of being heard and given a(n) (often fake) signal report. One contact lasts less than a minute, then the DX station moves on to another contact. What you hear in this recording is an avalanche of many stations sending their calls, then a pause, while the DX station, which you can hear faintly at a very high pitch on the right, makes one contact, then another avalanche of calling. If this sounds nuts, I agree. But it's fun to listen to with the binaural receiver.

The recording was made on a Samsung UP-MT6 portable mp3 player, which was the only recorder I had at hand at the moment when the opportunity offered.