|Enigma ID||X06, X06a, X06b, X06c||
|Emission mode||USB + carrier, USB, AM|
|Known counterpart stations|
Mazielka is a calling system used by the Ministry of Foreign Affairs of Russia.
Usually transmitted in USB mode with a carrier, it consists of a roughly 2-second string of 6 tones in succession, 333 ms per tone, followed by a 1380 ms pause, repeated over and over. The tones have the following approximate frequencies, in hertz:
In normal operation, strings of only unique digits are used, allowing 720 different combinations, although far fewer than that are actually being used. Each sequence has its own set of HF frequencies assigned to it, with typically one or two being the ones the sequence is usually heard on.
In the past, Mazielka acted as an alert system for unscheduled diplomatic transmissions using the now largely obsolete RTTY and Serdolik modes. Currently, Mazielka is most commonly heard on semi-fixed schedules in one of the following ways, which depends on the Mazielka sequence in question:
- Before a Perelivt contact, with the MFA Moscow side using either the same frequency as Mazielka, or one of the alternative frequencies of the given Mazielka sequence.
- Before a Perelivt contact that will take place 15-45 minutes later on completely different frequencies. The Mazielka callup is normally switched off before the Perelivt contact begins.
- As a follow-up after a Perelivt contact on different frequencies. These are usually shorter than 10 minutes.
When not in normal operation, Mazielka can be heard using various non-unique digit strings, such as 123456, 111666, 121212, and 111111. In one particular case, the sequence 111666 can be heard about an hour before European E07, M12, XPA, and XPA2 schedules, on the frequencies these schedules are going to use, in ascending order (regardless of the order used on the schedule). It is unknown to what degree Mazielka is related to the Russian 7 operator.