[TowerTalk] PL-259, Teflon or not?

[Tom Rauch]

> At higher frequencies, Teflon is less lossy than just
about all other viable
> insulators for connectors.  Air being the least lossy but
hard to hold a
> center contact without something more solid.

It might be useful to point out there isn't any *electrical*
difference worth mentioning between Polyethylene, Teflon,
and a number of other materials. Teflon just handles heat
better. Polyethylene would make a poor mechanical insulator.
There is an old wive's tale that Teflon has less loss than
insulators like Polyethylene.

You're right about HF and connectors. Even Delrin and Nylon
are OK because the electric field is low and the insulated
distance along the line is short.

When I test barrel connectors, some Delrin and Nylon
connectors have significantly less heating than Teflon.
That's because the conductor resistance losses dominate, and
many Teflon connectors have a very resistive gold colored
conductor. At HF, dielectric losses don't matter much. The
primary loss mechanism is conductor resistance.

73 Tom