Pull the antenna connection off of the radio. If the signal is still present its definately an internally generated birdie. If not still present you may want to search around the house as its probably some computor or processer generated noise.
No It has to be something else i took the antenna off and i got nothing then i put the small stock antenna on and got the sound but not that strong then i put an antenna on that i have on the roof and i get a strong signal. I can hear it on my Pro-95 and Pro-164 its weird it sounds like a wistleing in and out almost like a metal detector when they are searching someone.