Just want to reiterate that John and Jim both speak the truth. Years ago I
used to cart an old GAP vertical dipole down to the Texas coastal islands every
year for the IOTA contest. The difference in low angle performance from that
GAP when mounted on the beach right up by the surf was remarkably noticeable.
I also used that GAP antenna up in the piney woods a few times and a
horizontal dipole fed with ladder line hung at 100' would make the GAP
performance seem like a dummy load... my conclusion was that the vertical
dipoles tend to produce something around unity gain unless you can get them
over saltwater, which will wake them up. Otherwise, you are better off with a
horizontal dipole provided that you can get it up high enough (just say half
wavelength minimum or you are wasting your time) to produce some reasonable
amount of low angle performance.
Just my 2 cents worth...
73
Matt
KM5VI
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of Jim Brown
Sent: Thursday, October 22, 2020 1:55 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Vertical dipole other choices?
On 10/22/2020 9:39 AM, john@kk9a.com wrote:
> A vertical does not really have a low radiation angle unless it is
> over a perfect ground. Assuming that your vertical dipole base is
> near the ground I would expect the 115 ft high dipole blow it away the
> in the favored direction.
This is only true in the extreme case when "ground" is salt water. What better
ground quality does is strengthen the vertical pattern. Mounting height affects
both the shape and the strength of the vertical pattern, and a vertical that's
high over salt water has very strong lobes. I posted links yesterday for a
study I did several years ago on the topic.
k9yc.com
73, Jim K9YC
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