[TowerTalk] Twinax (definition)

[K0FF]

Twinax or twin-axial cable is a shielded twisted pair with precise
electrical characteristics, used primarily for data cables in IBM midrange
systems.
It comes in 78 Ohm, 100 Ohm and 120 Ohm versions with a variety of covering
and insulating material, including Teflon. Teflon is used on cables that
must be run overhead in false ceilings, where that space is also used as a
return plenum for the air-conditioning system (typical office building),
hence the name "Plenum Rated Cable". It must be flameproof/fireproof so that
the material won't propagate fire in a high air environment. even at that,
when a wall is penetrated, the hole must be sealed with a special fireproof
putty.

As far as ham applications, I can think of no feedline uses offhand (that
something else wouldn't work better). One excellent use comes to mind is to
rewire the telephone jacks in your house with it, and eliminate a big source
of RFI ingress..
Twisting all the conductors together at both ends will make it suitable for
radial or Beverage wires.

Connectors are available at Gateway Electronics in St. Louis, if you are so
inclined.

Geo>K0FF




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