[RFI] Pole mounted lightning arresters?

[Leonard Halvorsen]

An arc inside the transformer oil drum, perhaps. That might deaden it to
the Ultrasonic Dish.
   Corroded connection on one end of a winding.
   An arc between turns.
     "    "   to the core or the inside of the drum.
   Maybe something more like corona than a hard arc.
   There may be a spark gap (over-voltage protection) on/inside the drum.

What hardware, other than lightning arresters (arcing internally) would
> not be affected by rain and I could not hear with the dish?
>