"Ed" wrote in message
news:hbRYf.4616$te1.2329@trndny03...
[snip]

Which brings me to a question. Sometimes, the CRT causes a real racket.
At others, none. Unless the amount of emitted RFI varies greatly, do
local atmospherics amplify or attenuate it?

The amount of RFI can vary greatly. The harmonics from the sweep circuits
will change with the resolution. The RFI from the video will change with
the picture information.

Frank Dresser