[HATS] Helix antenna info...

[Christopher (Chris) W. Boone]

WOW!!! I got a ton of replies of my posting on the Helix horiz TV 
antenna...and as many requests for the article...

I am working on the master list to send out by Monday..I may try
to scan the articles in and email them or just fax them out..
but here is a little prelim info:

These antennas are omni directional...it is built in sections...the upper
section is one helix wound in one sense, the bottom section is wound
in the opposite sense...this cancels any vertical radiation and the
horiz remains...KTVT Channel 11 (CBS Owned) in Dallas used one for
the past couple of decades...it recently was removed because of the
DTV construction and they replaced it with a stacked PANEL for DTV
and a stacked batwings for 11 and 13 NTSC (the new structure was
over 150ft in length...it now has a 18deg lean in it due to Andrews
not doing the panel construction right...court case to follow :)

Gain is roughly determined by the number of turns per section and
number of overall sections..to add 3db you merely double the sections
and feed with a proper phasing harness...I will be taking pictures
of the TV 11 Helix and Gene at ATV Quarterly has asked me to write
it up for publication...I will also include other antennas such
as the "Panel Zig Zag" and of course the ever popular Batwing (aka;
SuperTurnstile) which can be easily made for use at 420-440 with
square tubing and stamped sheets of aluminum for the actual elements..

ALl the antennas above are 50ohm fed.....and are DC grounded! (Lighting,
etc protection)...

Looks like this will be an interesting article and I hope everyone
learns something new from it...BTW for those with a Micro Computer
Center or good technical bookstore, check the book series "ANTENNAS"
by Yo and Lee....I think Vol III or IV is the one that deals with
broadcast antennas and has a lot of the information on these antennas.
(The book are $95/volume but damn well worth it)..

Hope that gets the appetite wetted just enough....

Chris
WB5ITT
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