S10 – Czech Lady Numbers Station Profile

S10, known as the Czech Lady was one of the few number stations that a government agency has released details about.  The station was run by Czechoslovakian military intelligence, and was first spotted around the late 1970’s.  It used both a male and female live voice, and had many variants.  S10 is also believed to be the same numbers station that Czech Spy Erwin Van Haarlem received his instructions from.  It’s final message was sent on January 1st, 1991.

The station was originally named “Bulgarian Betty”, but this was incorrect and was changed to Czech Lady.

On January 23rd, 2015 the Swedish Security Service released details on the use of S10 on their website.  They also released a recording from their own archives and reveal its use during the cold war.  The station was from Czechoslovakia and the intended recipient was a Swedish Spy.  The recording they released was actually a live read message and not automated.

Message Sample (N&O, June 1981)

Station Structure

The original format of S10 was used from 1970’s until the early 1980’s.  There is some confusion in the Conet Project and elsewhere where S10b was ID’d as S10.  S10b was the later format with 5 rising tones and slightly different intro.  It first played “Song of the Lark”,  written by Pyotr Ilyich Tchaikovsky from a tape.  See the variants listed below to see the format changes.

Intro Preamble Message Outro
555 082 555 082 13 28 rovná se, rovná se 79881 79881 89658 89658 … rovná se, rovná se 13 28 000
3-figure recipient ID 3-figure recipient ID 2-figure ID, unknown purpose Group count “Equal sign” 5-figure paired groups “Equal sign” 2-figure ID, unknown purpose Group count
Repeated 2x Repeated 2x Repeated 3x Repeated 3x Repeated 2x Repeated 2x Repeated 2x Repeated 2x
Repeated for 6 minutes

Numbers Station Summary

Nickname: Czech Lady
Activity:
Inactive
Emission mode:
AM
Voice Summary:
Automated and live female voice. Also used a male voice.
Believed Country of Origin:
Czechoslovakia / Czech Republic
Family Relatives: G18(?), M10, M07, S10d(?)
Station Family:
Family 9 Subfamily A “Czech”

Variants

S10a

S10a is variant that had a 555 idler. Ex.  “555 (x3) 000 Konec”. Emitted in AM.

S10b

S10b was a variant that had a different interval, using 5 rising tones that are similar to the tones used in G18.  Rovná se was replaced with “pozor” and the 000 ending was replaced by “konec”

S10c

S10c was a variant that had an additional 3 figure ID.

S10d

Nicknamed “Bulgarian Betty.”  Might not be a variant but it follows the same setup.  Despite the name, the stations language is actually in Czech.

S10e

S10e was a variant read in Slovakian instead of Czech.

Sources

Simon Mason’s Website
Spectogram – The Conet Project
S10 Recording – Numbers & Oddities
Lyssna på ett hemligt telegram (Listen to a Secret Telegram), by The Säkerhetspolisen

Further Reading

ENIGMA Newsletter Issue #15 (July 1998), Page 47