[TowerTalk] TowerTalk Digest, Vol 219, Issue 22

[Drew Vonada-Smith]

Dave.

A vertical is omni in azimuth, while a dipole has some directivity.  This, the dipole has more gain in the favored direction, even in free space.  This is normal.

73,
Drew K3PA
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Message: 2
Date: Mon, 15 Mar 2021 11:26:00 -0400
From: Dave Sublette <k4to.dave at gmail.com>
To: kj6y--- via TowerTalk <towertalk at contesting.com>
Subject: [TowerTalk] Vertical question
Message-ID:
	<CAKynJKn0WE5EvR27LMMhnTgueTJh5A=97dR1tW2rzS1-GeXiLQ at mail.gmail.com>
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Good morning,

I recently changed my elevated 160 meter quarter wave vertical with 8 full sized radials to having only 1/8th wave length radials and only four of them.  It is working great.  So I thought adding four more radials might improve things.

But before I went to all the trouble I decided to model it and see if there was a difference in performance of the 8 radial version compared to the 4 radial system.

I use a modelling program called Antenna Model.  The result of the comparison is this:

The 4 radial system showed a gain of 0.92 dBi with the main lobe at an elevation of 20 degrees.

The 8 radial system showed a gain of 0.93 dBi and an identical elevation pattern.

My question is:  Why is the gain figure so low?  A dipole exhibits 2.14 dBi gain. Why doesn't the vertical show gain?

And lastly, I think these results tell me it isn't worth the effort to add four more radials.

Your thoughts?

Thanks & 73,

Dave, K4TO

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