S17c calling "777" plus X06

S17c changed their frequencies as a part of its seasonal changes. Usually 5301 kHz is noisy and weak in my QTH. Lately I dial my tuner on S17c try to see what surprise the mechanical YL have for us. Today she called "777" along with a X06 transmission which was stronger. Here it is a sound sample, 5301 USB 1250z. The message was "62027" (as usual a "0" is in the middle).

Mysteries can be melodic

Accidentally I stumbled upon this one. Log details: 8147 kHz AM 2214z-2215z. Known as X06, it is believed to be a Russian SELCAL system nicknamed "Mazielka".

There are hundreds of different tone combinations that can be heard. I know at least one dedicated fan of them, but anyone agrees that the tones are melodic and distinguish from all the other strange-sounding signals found in HF.