A unique trait of OLX was that it sent QSL cards to anyone who requested it. No other station has done anything like this. It’s one of the only instances where a government has also confirmed their use of a numbers station.
S05 was first operated by Czechoslovak State Security (StB) and then the Czech Republic. The numbers were read in Czech with an automated voice. It was one of the few number stations that operated under a ITU-registered callsign, this stations callsign being “OLX.”
Interestingly, S05 was officially assigned to CETEKA (ČTK), the Czech press agency and it’s allocated frequencies. Replaced in the early 1980’s by S05a. The station and it’s variants were officially all inactive in 1996.
S05a (Formerly S15)
Formerly ID’d as S15. S05a is a variant with rapid dots in place of call up. Recording by Numbers and Oddities.
S05b (Formerly S16)
Formerly ID’d as S16. S05b is an S05 variant without any null messages.
Station Format
Five minutes prior to transmission on the hour, S05 sends the callsign OLX in Morse code “VVV DE OLX OLX.” A three digit message ID repeas for give minutes beginning on the hour or half hour. This number indicates whether or not the transmission will carry traffic. If not, the transmission ends after 2 minutes.
Numbers Station Summary
Nickname: OLX
Activity: Inactive
Emission mode: AM
Voice Summary: Automated woman’s voice. Czech language.
Believed Country of Origin: Czechoslovakia
Family Relatives: M06a, M06
Station Family: Family 9 Subfamily B “Czech”
Sources
Numbers and Oddities, S05a recording
Simon Mason’s S05 OLX Page (Archived)
The Conet Project, S05 Recording
