1. Introduction

For the first time I heard these beacons in Morse code around 1970. Many of them are still alive and are regularly observed by many utility specialists. They are operated by the CIS Navy at the Fleet HQ locations.
Single-Letter-Channel-Markers have used many frequencies in all the years and many are obsolete now, Cluster-Beacons however kept their frequencies.
Ary Boender 1996 published details concerning the purpose of these transmissions;
saying that Single-Letter-Beacons are used as Channel Markers to keep a certain frequency free for traffic and that Cluster-Beacons may serve as propagation indicators.

2. Single-Letter-Channel -Markers

Single-Letter-Channel-Markers quite often work in parallel and only at certain times. We can't predict their operating skeds, certain stations may disappear and then show up again after months.
Although assigned to Navy HQs RDF not always points towards the HQ location; the transmitter sites may well be at other places.

Occasional transmissions in Morse code or FSK CIS 36/50 mode from Navy stations interrupt the continous stream of the same letter with messages mainly to collective Navy callsigns. At rare occasions even voice messages in Russian have been observed.
One example is "P" on the frequencies 3699.5//3837//3291 kHz, which quite frequently is interrupted by CIS 36/50 traffic and Morse routine messages to RDL and other callsigns.
It is interesting to note, that all CIS 36/50 traffic, so far heard on Channel Marker frequencies, will decode upon the same sync string like on VLF. It is obvious, that a multitude of transmission channels make sure the information will arrive.

The table shows just a small selection of Channel Markers and its origin.

3. Channel Marker Frequencies

Frequency kHz	Letter	Controlled or transmitted from
3203.8	L	BF Headquarter, St. Petersburg (RUS), not confirmed. Tirana mentioned as well.
4424.8	L	BF Headquarter, St. Petersburg (RUS), not confirmed. Tirana mentioned as well.
4325.8	R	Izhevsk (RUS)
5465.8	R	Izhevsk (RUS)
5312	D	BSF Headquarter, Sevastopol (UKR)
7077.5	D	BSF Headquarter, Sevastopol (UKR)
15064.7	V	Khiva (UZB), not confirmed.
3166.8	P	BF Headquarter, Kaliningrad (RUS)
4043	P	BF Headquarter, Kaliningrad (RUS)
5111	P	BF Headquarter, Kaliningrad (RUS)

4. Cluster Beacons

Cluster Beacons are grouped around a centre frequency which always is letter "C" for the Navy Headquarter in Moscow. The frequency slots are 100 Hz apart. One or several slots can be active at the same time. It seems, the Cluster Beacons are on the air at times of increased activities of the Navy (exercises, accidents, etc). Skeds are however not predictable. The purpose of these beacons is not known, nowadays they most probably only serve as propagation indicators. To my knowledge no messages have been heard so far on the frequencies.

The following centre frequencies are used:
3594, 4558, 5154, 7039, 8495, 10872, 13528, 16332 and 20048 kHz.

The slots are assigned as follows:
.7 D Sevastopol UKR
.8 P Kaliningrad RUS
.9 S Severomorsk RUS
.0 C Moscow RUS
.1 A Region of Astrakhan RUS
.2 F Vladivostok RUS
.3 K Petropavlovsk Kamchatskiy RUS
.4 M Magadan RUS

This is an example of a distorted transmission, something that might happen now and then. C and S channels are ok, but the third character is garbled and doesn't fit into a 100 Hz slot.


Top of page