Ukrainian sz

Operating agency Unknown

Enigma family ...
Country Ukraine

Ukrainian (icon)

Operational detail pages
Active stations E17z, S06s
Inactive stations

This operator is unidentified and of uncertain origin. It runs S06s and E17z, which seem to have obvious origins in the Russian E17, E06 and S06 stations. However their formats are slightly different, E17z 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 between only 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[1]. This operator also follows clearly different scheduling habits: there are no next day repeats, messages being repeated the following week instead. Thus, and despite some habitual confusion from reporters, S06s and E17z operations really have nothing to do with the Russian 6 operator.

According to this recording, this operator also has a German voice available, although it was never reported in an intentional transmission or as a normally operating station.


The primary transmitter site is located north of Rivne, Ukraine. The other alleged, but unconfirmed location is the former Radio Ukraine International transmitter site in Lviv.[2]

Observations of the S06s ID 524, sending at 06:30 & 06:40 UTC using frequencies within 22 & 20 MHz respectively, 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.

On 31 October 2016, and throughout the first week of November that year, operator chatter was regularly leaked on the air 10 minutes before and throughout a scheduled S06s transmission: the chatter referred to regular transmitter warmup and setup procedures of this operator[3]. It also revealed the operators using the Ukrainian language among themselves, as a supporting piece of evidence for the origin of this station.

Test frequencies

Known test frequencies are 5140, 5252, 5454, 6280, 7635, 8080, 8180 and 10240 kHz, for E17z, using ID 274. These tests have been seen to simulate advanced transmission failure scenarios, going as far as fallback to live operators.


  1. ENIGMA 2000 Newsletter #87 (March 2015), pp. 45-48 [accessed 22 September 2018]
  2. Numbers & Oddities Newsletter #212 (May 2015), pp. 9-10 [accessed 24 September 2017]
  3. Numbers & Oddities Newsletter #229 (October 2016), pp. 14 [accessed 16 July 2018]
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