|Operational detail pages|
|Active stations||E11, S11a, F11|
|Inactive stations||G10, S26, S11, G11, M03|
This operator, who is believed to be a Polish intelligence agency, is one of the major actors in the field of numbers stations on shortwave. It currently runs many active schedules of E11, S11a and F11.
In the early days, this operator ran a first (known) generation of numbers stations: G10 and S26. They both used the same voice format featuring musical call-ups. In the late 1970s, these stations ceased to transmit and were replaced by a new generation of stations, with an updated, similar but slightly different format, dropping the musical call-ups: voice stations in different languages E11, G11 and S11, and the morse station M03. In 1994, S11, which used voice samples in Polish, was replaced by a version using Russian instead, which eventually received the designator S11a.
These stations being used for a lower and decreasing number of schedules, G11 has ceased activity since 2014, and M03 since 2016. However overall, the activity and number of schedules operated by this agency follow a steady increasing trend.
There exists a digital counterpart to the analog voice and morse stations: F11. It is not operated as a different, independent station. Instead, it is usually run in parallel, on the same schedule, with analog modes: F11 is sent 15 and 10 minutes before the analog transmission. Not all analog schedules are preceded by F11; and conversely, sometimes an F11 schedule is not followed by any analog transmission. Recently, the use of F11 seems to be on the decline.
This operator used the Windows XP OS as of 2014, as evidenced by leaked shutdown sounds after the last transmission of the day during that summer. Sometimes, two identical transmissions are sent at the same time on the same frequency, but usually the operators correct this quickly.
This operator is believed to use one TX site, located in the Warsaw area. This can be evidenced by:
- signal triangulation using direction finding equipment
- receivers in the Warsaw area picking up the ground wave
- several instances of scheduled transmissions being omitted during thunderstorms over Warsaw
- Warsaw being the capital of Poland and the most likely location for operations of a governmental agency
See also this blog post.