Interesting. When I was 14 and 15 and 16 years old living in Omaha
Nebraska, I operated thousands of hours of 15 meters. I heard this same
type of signal at various times. Occasionally, it would travel across, and
wipe out the entire 15 meter band and you could bearly copy signals unless
they were super loud. I never knew what this was until now. Cool.
Phil.
K0NX