E11 Oblique (Number Station)

E11 Null Message Recorded on WebSDR.

E11 Message Recorded on WebSDR (Incomplete)

E11 (also known as "Oblique") is a number station located in Warsaw, Poland. It is believed to be operated by the Polish Intelligence Agency but it is unconfirmed whether this is true. It was originally read out by a live voice but then around September 2002 changed to digitization.

Format

Oblique uses two different formats, the "Null" format and the "Traffic" format, null messages usually open with a 3 digit ID, followed by Oblique, the number 00 followed by "Out" ending the transmission.

The Traffic format begins with, once again, a 3-digit-ID, followed by a group count "Attention" and then 5 digit paired groups with pauses after every 10 pairs, "attention" and then followed once again by 5 digit paired groups with pauses after every 10 pairs, and then the transmission is ended with "out"

History

E11 was first reported in the 1980s, gaining attention for very small actual traffic and usually just sending null messages, and it wasn't until 20 years later in the early 2000/s that it actually began to be a place for real traffic.

Originally E11 used a different voice featuring a polish accent, but the voice that is currently used started in 1990

In 2003 - 2009, a variant E11b existed, which included the group "77777" as the first, second, last but one, and the last group of the messages.Such messages were sent on a randomly chosen week once a month These messages stopped around March 2009, but the one a month messages still continued, E11b has since been inactive.

E11 had another variant known as 'E11c' that ran on a different schedule. It used an alternative null message format which included 4 digit segment in the middle of the ID. The station was first logged on the 22nd July 2010 and was last logged on April 13th 2013

In 2014 from April to August E11 was notable for frequently using the Windows XP shutdown sound following the last, scheduled, broadcast of the day, but this didn't always happen.