Topband: Vertical vs inverted L question/opinions

[DALE LONG]

Tom, that gives me an idea..

An artificial tree (metallic) about 130 feet tall.  Wonder how many of them I could sell.

Where's the nearest patent office?

73,

Dale - N3BNA



________________________________
 From: Tom W8JI <w8ji at w8ji.com>
To: topband at contesting.com 
Sent: Sunday, August 11, 2013 10:21 PM
Subject: Re: Topband: Vertical vs inverted L question/opinions
 

> Why is an inverted "L" apparently so popular on 160 when it wastes so much RF as a cloud warmer?

"Wastes so much RF" is sort of subjective.

Comparing an L to a T, both 65 feet high and resonant over 50 radials, the T has almost exactly the same average ground wave signal. There is only a tiny fraction of a dB difference. In some directions the L is a tiny bit stronger, and in some directions the T is a tiny bit stronger, but it all amounts to a fraction of a dB.

The only real major issue is the L has about 0.4 dB front-to-back.

They aren't that much different in impedance, either.

I'm not sure anyone would see any difference, except perhaps the L fills in the deep vertical null a little bit.

This changes if the L and T are not self-resonant. Even so, unless the L is made so long the current maximum moves out of the vertical section, there isn't really what most would consider a significant difference.

In my opinion, the choice is mostly a matter of what best fits the supports. Unless you try to use Tree for an antenna, then you might be 20 dB down.

73 Tom 
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Topband Reflector