Not many people knew about these for a long time but the word is starting to spread.
For decades, especially since the Cold War, unidentified radio transmissions on the shortwave bands have appeared, at all hours of the day, only to transmit ciphers and codes in the form of morse code, spoken numbers, and occasionally encrypted digital modes.
No one has ever claimed ownership and no governments have acknowledged the existence of these stations.
I used to pick up a Cuban numbers station every night around 3 am EDT on 5.883 MHz. I'd sit on the back patio and just listen in the dark against an audio backdrop of crickets.
A few years ago, the station on 5.883 MHz went away only to be replaced with a similar sounding station (same voice reading the numbers in Spanish) with an additional digital mode following the spoken words (which turned out to be a format called RDFT: user link on www.sigidwiki.com).
Here is a good write-up about the "HM01" station I hear often on 10345 kHz around 3 am EDT these days (though I haven't heard it for a few months now): user link on swling.com
There is a schedule here: user link on www.qsl.net
It's a little eerie, perhaps, but fascinating. If I happen to be up late and have a shortwave radio handy, I'll tune around and see if I can find it.
Anyone else interested in this kind of thing?
