Numbers stations
A numbers station sounds like a flat, often synthetic voice reading groups of digits on shortwave, sometimes after a tune or a chime. The messages are widely believed to be for intelligence officers abroad, and to be sealed with a one-time pad, which cannot be broken without the matching key.
What does it sound like?
What are they?
Shortwave stations that broadcast formatted groups of numbers (or letters) on regular schedules. Nobody officially claims them; hobbyists catalog them by a naming system where E means English, G German, S Slavic languages, V other languages and M Morse.
Why are they thought to be unreadable?
They are believed to use a one-time pad: each message is combined with a random key that's used once and destroyed. Used correctly, it can't be broken without the matching key, so anyone can hear the numbers, but the messages are widely believed to be unreadable to outsiders.
Famous examples
- The Lincolnshire Poacher (E03). A woman's voice reading five-figure groups, opened by a few bars of an English folk tune. Last heard in July 2008.
- E11, “Oblique”. A female English voice, still active, on schedules that change three times a year.
- HM01 (Cuba). A Spanish voice plus digital data. Off the air since August 23, 2024, when its transmitter failed.
- V32 (Persian). Appeared on February 28, 2026, about 12 hours after US and Israeli strikes on Iran began, reading digits after the word “tavajjoh” (“attention”). Monitors list 7910 and 7842 kHz at 02:00 and 18:00 UTC.
How can I hear one?
Hobbyist groups publish schedules; Priyom.org is the best-known. Most are heard with any shortwave radio in USB mode, at the listed time and frequency.
Hear it live
- University of Twente WebSDR (Enschede, the Netherlands)
Times and frequencies change often. Check the Priyom schedule for a station due soon, then enter its frequency in the receiver (most use USB).
These are free public receivers run by other people; we only link to them. You'll hear the signal only if it's on the air right now and conditions carry it to that receiver, so if it's quiet, try another time. Links last reviewed 2026-09-28.
Easily confused with
- Time stations: they also speak numbers, but tick every second and give the real time
- Contest exchanges: hams trade numbers too, but two voices, with call signs