It amazes me that the resistance is lower in summer than in
winter. I had expected the opposite.
There are no trees near the aerial.
When it rains or in fog the resistance rises considirable, as
indicates by the aerial current dropping by up to 25%.
Could that be due to water particles being heated in
the field around the aerial? Or is it only caused by increased leakage via the
aerial insulators and the feed-in?
You could check for leakage on the antenna wire with a "megger".
You may also have induced losses in the wall of your house and loss happens to
vary with moisture conditions (could be checked before and after a hosing
down). A possible countermeasure is to increase the spacing of the
antenna "upwire" from other objects (which reduces the field strength and
induction loss in the other surface?).
73, Bob
