Being conductive and being lossy are not the same thing. You may have
both situations, or one, or the other; however "not being conductive"
does not necessarily mean "not lossy." The microwave test is hardly
conclusive unless you notice it heat up. Other testing is more
sophisticated.

73's
Richard Clark, KB7QHC

Ohhhhh! I get it now. Its like why some kitchenware is ok for the microwave and
some not. The RF might be heating my spacers and if the spacers are the wrong
stuff, we have a melt down! Darn....why did all those neat industries making cool
things out of glass and ceramic dry up and disappear.....

with the collectible price of simple glass antenna strain insulators you would
think some industry would fire it up again, and while they are at it they could
make some of them out of purple glass and the collectors would go nuts unleashing
all kinds of cash on them. How hard is it to make things out of glass?

ps. has anyone actually heard of a diy ladder line having a spacer melt down
while running power? no reason why it couldn't happen....

Now that I understand, I will at least put my prospective spacers through the
microwave test....

-bill