These are Single Letter High Frequency Beacons (SLHFB)
used by the Russian Navy. They are part of a USSR/Russian
naval HF network that dates back to the Cold War and are
still in use today.

Some links on the topic of SLHFB's are below.....

http://www.cvni.net/radio/nsnl/nsnl32mx.html

http://www.dxworld.com/markers.html

http://home.luna.nl/~ary/chmarker.htm

http://www.iaru-r2.org/monitor0211_e.htm

http://www.geocities.com/n2uhc/cc/apr98.html



"GeorgeF" wrote in message
link.net...
It is possible that we have a spy/numbers station in the 75 meter ham
band? At about 0305 there has been a strong signal (S9 at times) on
3699.5 KHz sending the letter "P" over and over. Been listening for
10+ minutes and non-stop "P" (.--.). Another station came on freq and
sounded like he was turning up but the "P" never missed a beat...

Anyone know of a 75 Meter Beacon operating (but wouldn't propagation
beacons be required to ID ever 10 minutes?) on 3699.5 KHz? Or is this
a 'spy numbers' station?

George - Daytona Beach, FL
http://www.MilAirComms.com