Nearby major powerlines?
Nope. As I wrote prior, you can sense the standing waves at various points around the area, but it pinpoints nothing (these wavelengths can emanate hundreds/thousands of feet from the source). Outside my house I can hear reflections from other houses, having eliminated the nearby houses as sources.
To be clear, when I write ‘sense’ it’s less eardrum than it is vibrato off the diaphragm and inside the skull. It’s impossible to describe without being exposed to it (’it’ being infrasound).
One thing I’ve considered is erecting large panel (the size of 2 sheets of plywood) to act as a deflector to at least give me a direction - and perhaps partial relief - from the constant cycling drone. There’s half a chance it could be one of the various ground transformers in the area, but without electronic means (working on that) I can’t pin it down.
Ironically, once again while typing it stopped for a time, and this time I realized a vehicle was going by (it came back).
Hmmmm. (more data)