Katok-65: a Russian voice channel of numbers and code words on 4224 kHz

What you hear

Most of the time, nothing. Katok-65 is not a marker, so there is no buzz, pip or squeak holding the frequency between messages; 4224 kHz is simply quiet until someone keys the transmitter. Then a voice, sometimes a man's, sometimes a woman's, reads a message in Russian: a callsign, groups of figures, a code word, with the parts repeated so that the receiving end can check them. The message ends, and the frequency goes quiet again. The catalogue lists the channel as active as of 2024.

The name is in the pattern of the callsigns this family uses, a word followed by a number, and it is how listeners refer to the channel. On the Buzzer the messages are read by men; here a woman's voice is as likely as a man's, and that alone makes the channel worth a listen.

Who transmits and why

By the format of the messages, this is the same system that stands behind the Buzzer, the Pip and the Squeaky Wheel. Where those stations keep their channels alive with a marker and only occasionally break for a message, Katok-65 shows the other side of the same net: a plain voice channel on which the traffic goes out without any marker at all. Comparing a message heard here with one heard on a marker is the kind of thing listeners do to work out how the net is organised.

Who the net belongs to has never been stated. It is assumed to be military, as with the rest of the family, and the location of the transmitter is not given in the catalogue; the honest position is that the station is heard, logged and compared, and that its address and its purpose are inferred rather than known.

Everything sent here goes out in the clear. Receiving it is all a listener does, and the content, a list of numbers, is meaningless without the key, which nobody outside the net has.

When and where to listen

The channel follows the day and night habit of the whole family: 4224 kHz in daylight, 3218.5 kHz after dark at the transmitter. Both are in the lower part of shortwave, so by day the station is heard within a few hundred kilometres of its transmitter and at night across Europe. For a listener in the west of the continent, the evening on 3218.5 kHz is the better time; from eastern Europe and the Baltic states the daytime frequency is also workable.

Since there is no marker, the only way to know whether the channel is alive is to wait on it. The waterfall helps: a voice transmission shows as a sudden block of energy a few kilohertz wide, hard to miss even with the sound down. Messages are short, so it pays to record rather than to rely on memory.

The program sets USB, the standard choice for voice on these frequencies. If the audio sounds pinched or the voice is off-pitch, the transmitter may be using AM; try that mode.

In ShackDeck

Station catalogue → Mystery stations → Katok-65. The program picks a public receiver that covers 4224 kHz, tunes it and sets USB; you need no receiver, antenna or account of your own. For the night frequency, tune the same receiver to 3218.5 kHz when the daytime channel goes quiet after dusk.