[TowerTalk] Dipole fed with balanced line?

[Al Kozakiewicz]

Basically, efficiency is calculated by the ratio of radiation resistance to the sum of radiation resistance and system losses.  If system losses are zero, efficiency will always be 100% by definition even if the radiation resistance is miniscule.

Of course, it's not possible to build a lossless anything.

I can can make a counter argument if you broaden the defintiio of the term "effective".  A long radiator, while very efficient considering real world losses, might not be very effective due to the appearance of pattern nulls.

Al
AB2ZY

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From: towertalk-bounces at contesting.com [towertalk-bounces at contesting.com] On Behalf Of Paul Christensen [w9ac at arrl.net]
Sent: Tuesday, January 17, 2012 10:52 AM
To: Towertalk
Subject: Re: [TowerTalk] Dipole fed with balanced line?

> There is no way that I will believe that a "physically small radiator with
> a very low loss matching network" is as effective as a half wave antenna.

That's about ten decades of research reading to catch up on -- starting with
short Marconi base-fed vertical radiators, then moving on to the shortened,
but optimized "T" used at 1BCG for the transatlantic tests in 1921, moving
forward to Jerry Sevick's work in the mid '70s on severely shortened, yet
highly efficient vertical antennas.

With top loading for verticals, or end-loading for dipoles, super high
efficiency can be maintained.  I would start by reading Sevick's work as a
general analysis of shortened antennas, and also study how and why a
radiator's feedpoint Z, I, and E changes with radiator length.

Paul, W9AC

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