I have done some more work on modelling coax traps...

The article I wrote in March proposing a transmission line explanation for
the operation of the traps has been revised to compare some of the
alternative explanations to the transmission line explanation, the article
is at http://www.vk1od.net/coaxtrap/index.htm .

Bringing it all together, another article at
http://www.vk1od.net/coaxtrap/8040.htm designs an 80/40 trap dipole using
the bootstrap coax trap configuration, and models the antenna system
(including trap losses) on the two bands.

Feedback on the technique, errors, flaws etc are welcome.

Owen