Re: [TowerTalk] SteppIR 4 Element Yagi - Analysis and Thoughts

[Rob Frohne <frohro@wwc.edu>]

On Apr 14, 2004, at 5:13 AM, Bernard wrote:

>     Joe:
>
>         I was wondering if you or anyone else on this thread have 
> considered
> a single antenna (like a SteppIR) on a motorized tower where you could 
> raise
> and lower the tower to optimize to the angle of arrival.  I haven't 
> seen any
> comments on this subject and I don't know if there are any computer 
> programs
> that take propagation data, etc. and calculate the optimum height.  I 
> know
> that many "big guns" spend $1000s for that extra dB or two, but many 
> of us
> don't have the real-estate for multiple towers and/ or antenna stacks.
>
>         Comments, anyone?
>
>             73
>
>
>             Bernard, WA4OEJ
Hi Bernard,

I am working on that problem.  I just put up an old Tri-Ex THD-7122 
(122 foot in seven sections) crank up.  My small hand drill will crank 
it up to about half height without much difficulty, but I have a big 
drill on order that should crank it up all the way.  My idea is to 
leave it cranked down except when I want to test antennas out (or 
operate, which I seldom do much anymore).  It cranks down to about 25 
feet and is located by my shop which makes it easy to switch antennas 
on it.  I decided to do this installation because I had the tower, and 
because I live on the edge of a 60 foot cliff, and couldn't come up 
with a good height to put my antennas at using the HFTA program.  In 
one direction I would get good results at one height, but they weren't 
good at another.  I intend on doing some experiments to see how it 
works in the real world.

I have been working on some ideas on how to make a Steppir like 
adjustable antenna as well, because this tower won't  handle a big 
antenna like the four element five band quad I used before at my old 
QTH.  The idea is that this setup will allow experimentation more 
easily than a regular tower and all that goes with it.

73,

Rob, KL7NA/W7


--
Rob Frohne, Ph.D., P.E.
E.F. Cross School of Engineering
Walla Walla College
http://www.wwc.edu/~frohro/

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