SERDOLIK sync marker (idling)

24/06/15 16047.0 --- Russian Gov 0918 Serdolik sync marker

The sync marker sequence is sent alone or after a Serdolik Selcall as shown below

Serdolik Selcall and Sync Marker (courtesy of KarapuZ)

Serdolik, as several time reported in this blog, is a complex system used by Russian Gov/Diplo and designed to connect embassies and diplomatic missions. The link below is a little story of this system:
http://www.sozvezdie.su/museum/sura__posolskaya_svyaz_dlya_sssr/ 
Thanks to KarapuZ for the link and the Sedolik Selcall waveform.