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TopBand: Inverted-L

To: <topband@contesting.com>
Subject: TopBand: Inverted-L
From: w8ji.tom@MCIONE.com (w8ji.tom)
Date: Sun, 01 Nov 1998 07:24:33 -0500
Hi Russ,

> I plan to put up an Inverted-L for 160.  Do I need a balum?  Can I feed
> it with ladder line?  Is the longer the better or should I stick to +/-
> 170 feet.

I've had dozens of Inverted L's. They always seem to work about the same no
matter how long the are, as long as they are between 130 and 170 feet long.
Longer than that, and they quickly become high angle radiators and you will
loose DX performance.

If you feed it with ladder line, you will need a baluN at the antenna and a
balun on the tuner or a balanced tuner. It will load up with a balun, but
the feedline will radiate and that can detract from performance.

If you don't plan on using it on multiple bands, feed it with coax. Then
you won't need a tuner or a balun. Be sure to use a good ground system!

By the way, if the ground system is poor...or if you use elevated
radials...a choke balun is a good idea. Without a choke balun the antenna
has a little less efficiency (I measured about 1 dB) with an elevated
system. Also, if the ground system is marginal the feedline will carry
unwanted antenna currents back to the shack, and that may cause problems.

73 Tom 

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