I'm an occasional shortwave listener and have come across these several times. I've been fascinated by them for the longest time and have copies of several from the Conet Project on Irdial.
My band, The Five Foot Flame, recorded a song I wrote that actually deals with these stations and a listener's obsession with the woman's voice. Interesting song. You should check it out. It's called Monotone Love Song.
www.thefivefootflame.com
Lyrics are as follows:
Antenna's out the window
Fingers on the dial
And it's true, I've been waiting for you for a long while
Head upon the table
'Sieben, vier, fünf, three'
I'm not sure who this count is for
Could it be for me?
Are you calling out to me?
Bulgarian Betty, what's your sign?
'Achtung, achtung', baby you're right on time
Five 'til eleven, the metronome buzz
Your monotone love song calling me through the fuzz
Intention's out the window
Hot breath on the dial
And it's true, I've scanned the band for you for a long while
Pulsed from secret towers
You drift across the sea
And I'm not sure who this code is for
Could it be for me?
Are you calling out to me?
Bulgarian Betty, what's your sign?
'Achtung, achtung', baby you're right on time
Five 'til eleven, the metronome buzz
Your monotone love song calling me through the fuzz