[RFI] Start up Sound file...

[KD7JYK DM09]

I've heard this sound in the past and seen/heard a mercury vapor lamp used 
as a yard light produce this sound near a friends house a few years ago. 
When the light finally gets "hot" enough, as far as we could tell, it was 
winter, it stops flickering and this sound stops.

I've also heard a similar sound from a failing/flashing LED streetlamp, 
although not as raspy.

Kurt