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Old 3-Apr-2019, 6:33 PM   #7
tripelo
Senior Member
 
Join Date: Jan 2010
Location: Dallas, TX
Posts: 127
Channel Master TW: Traveling Wave Antennas

Quote:
Originally Posted by bobsgarage View Post

But for now I figured I would submit some photos.
To me this is a challenge but to some of you installers you might
even have put these up in back in their day.
The antenna is a Channel Master 'TW' antenna. TW for traveling wave.
It was a revolutionary antenna in its day.

Previously, relatively high-gain antennas were narrowband (Yagis).

Broadband antennas for low & high VHF were much larger panel types
(CM Champion & BackStop etc, imagine a VHF 4-bays).

Or were some version of conical antennas (whisker-types for low and high VHF).

Announcement of Original Channel Master TW (image below)





Had one of these antennas until a tornado (years ago) took it out.

Found an advanced version of it on a scrap yard a few years back
It was in bad shape but could be restored.


Channel Master Super TW (image below)





Most of those elements that look like folded dipoles are not.
They are fat dipoles (the doubled part simulates a much fatter conductor for bandwidth).

In the original TW (1st image above),

All elements, except the last one, are driven.
The last one is an nondriven reflector.

The next to last element, is a shorted folded dipole (3-bar, for high impedance).

Even tho lots of driven elements, it operates on a different principle than log-periodic.

.
Attached Images
File Type: jpg TW Announce 1956.jpg (123.8 KB, 332 views)
File Type: jpg Super TW.jpg (88.3 KB, 333 views)
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