[TowerTalk] quad vs. yagi @ low height

[w8ji.tom]

Hi Dave,

By the way, this does not belong cross-posted on top band. I expect W4ZV
will be making that perfectly clear very soon!

This is one of those tar baby threads, because people who have loops and
quads love their loops and quads. It's sorta like telling someone he goes
to the wrong church, it's an emotional issue.
 
> the answer is... it depends on your definition of 'height'.  now,
> i don't mean to sound like a clinton answer, but here is the problem
> and what i have seen after lots of modeling.
> 
> if the top of the loops are at the same height as the peak of the 
> inverted v elements the inverted v beam is better.  if the loops are
> around a boom such that the boom is at the same height as the top
> of the loops (and therefor 1/2 of the loops is higher than the 
> inverted v elements) the loop beam will be better.

The theoretical maximum gain under PERFECT conditions (freespace) is just
over one dB!

Building an array of such elements, or placing the horizontally polarized
quad over earth, will always result is LESS than the theoretically maximum
gain over a conventional element. At some heights you'll find the quad has
a very slight amount of gain over a dipole element at the same MEAN height,
at others it can have negative gain. The bigger the antenna the less
advantage it has. That's why we almost never  see quad elements used a
building blocks in high gain arrays. 

Like all casual users of antennas, it is how we "feel" about the antenna
that makes it a "good" or "poor" antenna... not how well it actually works.


73 Tom

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