it's kinda like the chicken and the egg,
Can't really propose a solution, until you find the source.
But if ya can find the source, there may be no need for a solution
Cause if ya could find it, u'd eliminate it
Did it just start recently? Been kinda windy in the northeast lately.
Could it be Electrical powerlines blowin in the wind?
What happened when ya tried the kill all breakers except the one powering your TV tuner???
Recently I found a bad porcelain light fixture in my basement. Replaced it
because the pull chain switch was broken. Low and behold one of the wirenuts
had a loose wire, occassionally arcing. Fixing that didn't solve anything here,
but it certainly eliminated one potential source.