Jim -
I too am intrigued with the idea of modeling terrain. I think it's a
critical issue. If not flat, the land surrounding an antenna can have a
profound effect on the take off angle and effective height of an HF antenna.
About 20 years ago, as a younger engineer, I developed a program for
evaluating this effect and modeled the topography from my QTH along several
important paths. The results were very intriguing. They suggested that
some relatively low antennas would out perform higher antennas in many
cases.
Unfortunately, other life activities took precedence and I never implemented
any of the designs. Now, with a little extra time (although not much), I
have dusted off the old code and started looking into this again.
Sounds like Pete is very much aware of the terrain issue and has also either
developed tools or found existing ones to do the analysis.
73, Bob - W3YY
----- Original Message -----
From: "Jim Smith" <jimsmith@shaw.ca>
To: <towertalk@contesting.com>
Sent: Sunday, May 11, 2003 05:40
Subject: Re: [TowerTalk] tower height increse.
> Pete,
>
> I'm really intrigued by the idea of modelling terrain. Are you
> referring to the use of YT or something more esoteric?
>
> How did you determine the charateristics of the ground?
>
> This is an area about which I know virtually nothing but one in which I
> am very interested. This interest has come about through my very recent
> discovery that W6ELProp includes takeoff angles in its path predictions.
> Now I can figure out what angles are best for my QTH. What remains, of
> course, is how to get them. Still, I now know what I should be trying
> do do rather than relying on anecdotal "data".
>
> 73 de Jim Smith VE7FO
>
> Pete Smith wrote:
>
> >
> >
> > Terrain can make a huge difference, too. I've modeled the terrain of
> > a well-known New England contester in the direction of Europe, and the
> > modeling clearly shows that a tribander at 50 feet would be
> > significantly better than one at 70 feet, particularly on the higher
> > bands.
>
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
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