[TowerTalk] Re: When Less is More DE K0FF

[K0FF]

Hi EV, what you say is true, especially on HF, or any band where F2 ship is
involved. 6 and 10 meters present another challenge in that E skip is the
primary mode of propagation during summer months. E skip signals generally
arrive at higher angles than do F2 skip signals, that's why stacked
antennas, or 2 antennas at different heights, or antennas that have some
sort of beam steering work so well.

The whole point of my investigations over the past few years has been to
explore the various angles of arrival from different propagation modes and
target distances. My setup includes 3 sets of antennas, one at a pretty good
height above ground (11 el/105'), one adjustable from 23-70' (7el), and the
main array of 4 x 6el adjustable from 23' to 72' center of H frame, and also
adjustable in elevation 0-90 degrees.

Too bad such a setup can't be scaled up to 20M!

Geo>K0FF
-----Original Message-----
From: Evhen Tupis <evman@ix.netcom.com>
To: vhf@w6yx.stanford.edu <vhf@w6yx.stanford.edu>
Date: Thursday, August 17, 2000 6:46 AM
Subject: When Less is More


>Here's a start to an interesting thread.  First, let me say that my note
>is not an exhaustive discussion on the topic, rather it is a launching
>point to allow many folks to chime-in with their experiences with the
>hopes that we all could benefit.
>
>Playing a bit with some antenna modeling, I ran across an interesting
>phenomena; one that I knew existed before, but one whose practical value
>I just realized.  Angle of radiation is related to antenna height.  A
>simple concept, yet a very powerful one to exploit while determining the
>antenna you wish to erect.  How so?
>
>DX is determined, not just by the amount of RF you can pump out, but by
>the amount of RF at a given radiation angle.  It is possible for a
>3-element beam to outperform a 7-element beam on a DX circuit, provided
>the 3-element beam is high-enough to provide a lower angle of radiation!
>
>Here's the rub:  we often think "longer antenna" in order to work the
>DX.  We overlook the fact that we may be able to support a much smaller
>antenna on a much higher structure and be able to work even better DX.
>
>If you have an antenna modeling program, try it for yourself.  Chose an
>M^2 7-element 6-meter beam, placing it at 25 feet in the air (a typical
>installation, by the way...based on an earlier opinion poll on this
>remailer).  Plot the vertical pattern to your screen.  Now, "whack off"
>5 of those elements, re-optimize and put the remaining 2-elements at
>60-feet.  Plot the vertical pattern to your screen.  The lowest-angled
>lobe is placed significantly better for DX communication!
>
>Let the discussions begin. :o)
>
>Ev, W2EV
>
>
>
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