[RFI] Powerful RFI

[Lee K7TJR]

   Gary, your recordings sound exactly like the street lights here sound when their bulbs go bad. 
They cycle on and off from lit to dark at intervals that vary with the environment. 
I would look for either a high pressure sodium or mercury vapor light that is cycling on and off.
I have been most successful finding them with a BCB radio tuned to a high end blank spot and visually 
by driving around at night.

Lee  K7TJR Oregon