Nightly noise interference

[brucehvn <unet@xxxxxxxxxxxxxx>]

I have had X10 installed in my house for years.  Within the past
couple weeks, I started noticing that at night, a lot of my X10 stuff
wasn't working.  I've done some investigation with my ESM-1 meter and
have found that one leg of the house is experiencing outrageous noise
levels.  The meter shows a steady reading of over 50%.  The other leg
is fine.  My front porch light is scheduled to come on around 1/2 hour
after sunset and that seems to work most days, but it will never shut
off because sometime after that this huge noise starts.  I have a
coupler-repeater installed, but the noise is too great and it doesn't
help.

I don't think this is coming from my house.  Nothing much changes here
between night and day except for a few lights, but I'm sure they
aren't causing the problem.  I'm guessing it has to be a neighbor,
probably close, right?

What can I do about this?  I have a Panamax whole house surge
suppressor which has not been installed yet.  Would that be able to
block noise coming from outside, or do I need some other kind of whole
house filter?