This morning at 04:00 UTC I noticed the "S" beacon/marker transmiting
on 6752.0 kHz CW. Good signal in Athens, Greece. Ended abrupty at 04:05 UTC.
The S markers associated with 6752.0 kHz CW are Russian Navy. These go back to Soviet times. The Russians still like to use tried and tested methods and their maritime patrol aircraft such as the Tupolev Tu-142 Bear F and IL-38 May still have a Morse capability.
You'll regularly hear the Russian Navy Morse maritime patrol aircraft Morse nets sending S Markers on 4651.0, 6752.0, 8821.0 and sometimes on 10021.0 kHz CW. Those frequencies are ground control.
The maritime patrol aircraft reply on 4671.0, 6552.0, 8830.0 kHz CW
Ground control will send S Markers for 5 minutes every 30 minutes when the net is available to the aircraft.
They have been active every day this week due to exercises and testing in the Barents Sea/Arctic areas.
Active this morning/afternoon 30th August 2025.
Ground control sending S Markers on 6752.0 kHz.
Recording.
https://vocaroo.com/18x1awJkwL03The aircraft, if they have radiograms to send, will wait for the S Markers to stop and then trasmit.
Log from 30th August 2025
Ground conrol callsign QMF6 6752.0 kHz
Aircraft callsigns WPXX and CVOC 6552.0 kHz
1237 UTC
6552.0 kHz QMF6 DE WPXX QTC K
6752.0 kHz QMF6 QRV K
WPXX 06 05 1535 BT 0122 5894 5018 1455 1681 K (06 = Radiogram number. 05 = Number of groups in radiogram. 1535 = Moscow time.)
QMF6 R 06 K
1240 UTC
6552.0 kHz QMF6 DE CVCO QTC K
6752.0 kHz QMF6 QRV K
CVCO 09 03 1539 BT 2096 7274 1834 K (09 = Radiogram number, 03 = Number of groups in radiogram. 1539 = Moscow time.)
QMF6 R 09 K
Recording of aircraft callsigns WPXX and CVCO sending radiograms)
https://vocaroo.com/1h60qJyexnJNThe Morse net is still active as of 1400 UTC. S Markers noted on 4651.0 kHz, 6752 kHz and 8821 kHz 1400 UTC for 5 minutes.
