|Operational detail pages|
|Active stations||E17z, S06s|
This operator is unidentified and of uncertain origin. It runs E17z and S06s, which seem to have obvious origins in the Russian E17, E06 and S06 stations. However their formats are slightly different, E17z and and S06s featuring pauses between the five 0 of the outro. With time they also received different voices.
Painfully compelling divergences reside not in the format itself, but in the contents: this operator uses very short messages, usually only between 5 and 8 groups. They are not encrypted using one-time pads, but more probably use a codebook, as pieces of identical group sequences are often observed multiple times in different transmissions. This operator also follows clearly different scheduling habits. Thus, and despite some habitual confusion from reporters, S06s operations really have nothing to do with S06.
Direction-finding efforts have pointed to two separate transmitter sites in Northwest Ukraine: one in Lviv and one in Rivne. Observations of the Sunday 0630z/0640z S06s schedule using frequencies of 22 MHz and 20 MHz, given its particular propagation with a long skip zone, seem to indicate that a receiver located in Lutsk picks up the ground wave of this signal: this would be consistent with the nearby above locations in the same area.
Moreover, the presumed site in Lviv is an old Radio Ukraine International transmitter, which would be public infrastructure and could point to a governmental origin.
Known test frequencies are 5140, 5454, 6280, 7635, 8180 and 10240 kHz, for E17z, using ID 274.