[TowerTalk] Re: twinax
Tue, 30 May 2000 09:35:59 EDT
<< It there any good use for twinax for antennas? We have miles of the
stuff all over our wineries that has been decommissioned. Is it worth
bringing home? >>
If I understand the term twinax, and you are referring to two coaxial
cables, having separate shields and molded together in the same jacket, then
the answer is yes, definitely!
This can be used for shielded parallel transmission line, as described in
the ARRL antenna handbook, and is my favorite way to bring parallel
feedlines into the shack, straight to a tuner.
The coaxial lines can be connectorized and brought through a grounded
entrance panel, allowing easy disconnection and shorting when not operating.
Shielded parallel line can be run next to metal objects or through conduit.
Typically, you would bring your parallel line to the shack window, then use
the shortest length of shielded parallel line required to connect to your
tuner (assuming your tuner has a balun).
The effective impedance of the shielded parallel line is twice the
characteristic impedance of one of the coaxial lines.
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com