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Re: Fw: [TowerTalk] Combining antennas - My experiences - LONG

To: "Robert Shohet" <>, <>
Subject: Re: Fw: [TowerTalk] Combining antennas - My experiences - LONG
From: W0UN -- John Brosnahan <>
Date: Wed, 04 Feb 2004 10:10:25 -0600
List-post: <>
Bob, KQ2M--

This certainly is a classic case of YMMV.  And it is a bit like
comparing apples and oranges.   While both of our experiences
are probably based mostly on EU propagation--since there
just tend to be more of them--it is a completely different game
from CO to EU than from the east coast to EU.  You have a
lot more higher angle stuff to play with than CO.

In some ways my observations are based on much simpler
conditions.  The signals tend to all be much lower in arrival
angle AND my station was out on the prairie.  Very flat and
very lossy ground.   Hence I think my propagation was much
more text book than yours from its much more convoluted

And that is what makes this all so much fun.   There is no
ONE answer for anyone.   When the question is raised about
what height should I place my antennas the answer depends
on so many different things.   What do you want to work?
What do you want to maximize--QSOs or mults.   New mults
often come from low angle (deep) stuff where big QSO rates
come from getting sigs into the population-dense areas.
And you need to know things like sunspot cycle, etc.
Nothing beats stacks with a lot of switching flexibility.

The one thing different that I did in CO than most is that
my stack Yagis are always pointed in the same direction
on a rotating tower.   If I want a mult antenna (or two) they
are separate antennas on separate towers.  And I can
use a BIP/BOP switch to spray in multiple directions.
My 15 M station had a 4-stack of 7L Yagis at 40/80/120/160
that was fully rotatable.   Plus a 2-stack of 8L Yagis that
were at 40/80 ft on a small hill with a good shot to the
West.   The top one was rotatable to cover VK/ZL
and the lower one was fixed on JA.   The 2-stack of 8s,
when both were on JA was very comparable to the 4-stack
on JA.  And there was another 8L Yagi that was fully
rotatable on a wooden utility pole at 56 ft (effective height
probably a bit lower) that was used primarily for SE.
The combination was a killer -- with the ability to put
50% power on any combination of two of the three arrays.
And if I really wanted to be able to spray I could switch
in all three arrays with 50% of the power on the stack
and 25% power on each of the other two arrays.

I am sure your more complex terrain added a lot of
small, higher-angle lobes.  When I modeled my 4-stack
it was very clean in elevation with one main lobe and
everything else was many dB down--20 or more in every
case.   When I have had strong echoes off the moon there
was never any hint of any echo while the moon was in
one of the higher (very weak) lobes.   And the echoes
started at exactly the predicted point in elevation
and disappeared when the moon was 50% eclipsed
behind the mountains at 1.5 degrees.  (90% of the
moon echo comes from the 10% in the middle of the
moon--clearly confirmed by my results.

So my CO location was a classic case of simple patterns
and I think my results are certainly correct for my situation.
Clearly you site is much more complex--due both to the
unevenness of the terrain and the difference in propagation
to EU.

Nothing more fun than having a lot of antennas to choose
from and finding a lot of time to play with them before
a contest to see which ones work best under different

I guess it would be fun to play with antennas on the east
coast--but I would probably get depressed with the much
poorer propagation out west.   So I just sit out here (well I
did in the 90s) and try to pick off plaques on single band
efforts by picking the best band for the point in the sunspot
cycle and then doing whatever I could to maximize my
hardware advantage.   Think we did about 24 or 25 contests
from CO in the 90s (with W0UA doing much of the operating)
and won 11 or 12 plaques.  And some were new band
records at the time.  Feel like my efforts paid off and my
designs proved out to be pretty decent.  AND I HAD A LOT
OF FUN IN THE PROCESS--which is what it is all about!

Now if I only had some real money it would be a lot more
fun.  But all of my work was done on a minimum budget with
my only "advantage" being that I worked in RF and fell into
a lot of good stuff that I scrounged.

--John W0UN

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