Sunday, January 25, 2009

80 Meter Waterfall Pictures

Users of a web radio receiver in Europe have been reporting an unknown net or nets with waterfall pictures and seldom if ever a callsign ID. This uses frequencies around 3585 to 3595 in the 80 meter amateur band. The players are unknown, though a couple of e-mail addresses displayed are on Ukranian and German servers. Some players are almost certainly from the former Soviet Union.

Waterfall pictures are images that appear right on the spectrum tuning display given by most digital radio decoding programs. They've been around a while. They are created by scanning a graphic file into pulsed or amplitude-modulated audio tones corresponding to lines of pixels in the file. Some ham programs do this, as does a fun little shareware program called Audiopaint.

First I heard of the 80-meter activity was from a posting to the UDXF mailing list by Robert, KB7AQD. This particular station was creating large numbers right on the waterfall spectrum display. These corresponded to dB below full power, and as the power was lowered the numbers became fainter.

Today, the 25th of January, I ran across one station on approximately 3588 kHz USB. It was sending a graphic "CQ test" call, like this:

The e-mail address is actually for The bottom got cut off due to tuning.

Here's another one, sent at 1940 UTC today. It's a cute lil' doggie:

And here's an elephant, sent at 1945:

The blob on the spectrogram after the picture is a burst of BPSK125. It is an identifier, but probably not one for the same station. It decodes to:

DK4XI-8:72 Pskmail v.0.7.24 - 19:45:19

DK4XI is a German ham active on packet and APRS modes. It strongly appears that this identifier is for an automatic transmitter associated with a European PSK e-mail network not related to the 80 meter waterfall pictures.

Another picture, that I didn't get a spectrum of, contains the web address This goes to a CB/ham forum in Germany.