The T marker: a single Morse dash without end on 4325 kHz

What you hear

One dash. A pause. One dash. In Morse that is the letter T, and on 4325 kHz it is sent again and again, with the same spacing, at the same pitch, for as long as you care to listen. There is no faster way to describe a signal, and no simpler signal to find: on the waterfall it is a line of short, evenly spaced marks, and in the headphones it is a metronome with a single beat. It is the barest of the Russian channel markers, more minimal even than the D marker on 5292 kHz, which at least has three elements to its letter.

Who transmits and why

The T marker and the D marker on 5292 kHz come from the same net, and both do the job every channel marker does: keep the frequency occupied so that nobody else settles on it, prove around the clock that the transmitter and the path are working, and let the stations of the net recognise their channel by ear. One letter is enough for that. Which net, and where the transmitter stands, is not stated in the catalogue, and nothing is published about it that could be called reliable; the net is assumed to be military by analogy with the Buzzer and its relatives. Whether traffic ever interrupts the dashes is for the listener to discover. The signal is sent in the clear, and all a listener does is receive it; the background to the pair of Morse markers is in the D marker's article.

When and where to listen

4325 kHz sits between the 80 and 60 metre amateur bands, in a part of the spectrum that reaches a few hundred kilometres by day and across the continent at night. From eastern Europe, the Baltic states and Finland the dashes are a daytime signal as well as a night-time one; from western Europe, wait for dusk. Morse carries far on little power, so the marker is often readable when there seems to be nothing else on the band. The frequency is close to the maritime and aeronautical ranges around 4 MHz, so other Morse and data signals may be near it; the single-dash rhythm is unmistakable.

The program sets CW with a narrow passband, which puts the dash in the middle of the audio as a clean tone. A CW decoder will print a column of T's; a stream of a single letter is an easy first test of the decoder and of the receiver's tuning.

In ShackDeck

Station catalogue → Mystery stations → T Marker 4325 kHz. The program picks a public receiver that covers 4325 kHz, tunes it and sets CW with a narrow filter; no receiver, antenna or account of your own is needed. With the CW decoder on, the program prints each dash as the letter T, which is as plain as decoded text gets.