[Spooks] 5134 kHz - continuous tone 800 Hz in AM - what is it ?

[Pavel Troller]

Hi!
  As the subject says, for most of the day time I can hear a station
transmitting continuous 800 Hz tone in AM mode at 5134 kHz. It's not there at
nights (about 20:00 UTC and later I'm not hearing it).
  Once I heard the tone to drop and a few words spoken; the tone then came back
immediately. Unfortunately, there was so much static noise on the air that I was
not able to guess even the language.
  I receive it at Czech Republic, Northern Bohemia, near Ceska Lipa. The signal
"breathing" and strength indicate medium distance (in terms of SW :-) ); I guess
it's of European origin.
  I cannot find it on any of utility frequency lists I have. Is it known to
anybody there ?
  With regards,
     Pavel Troller