Sorry to rant, but I think it is enormously counter productive when a forum "archives" a topic and makes it no longer possible to add comments. I know this is probably Google's decision, and may not be under the control of the moderators.
I've been planning to add additional comments to my "Static When Capturing VHS Tapes" topic. I am extremely annoyed to discover it is no longer possible. I would like to be able to add a comment a decade or 100 years from now.
Anyway, I've encountered a video on YouTube with precisely the kind of audio static that I've been experiencing, Although I did receive several helpful replies when I posted, I'm wondering if this would help anyone elaborate on the probable cause. You need listen to only the first ten or fifteen seconds to get the idea.
It's called SUBURBAN LAWNS - JANITOR, posted by spadge321
Just to clarify, this video has nothing to do with me; I am providing the link to it only as a demonstration of the static.