RE: The Big One
I am encouraged by Peter's comments having to do with terrain.
Actually the antenna is 6 elements on a 110 foot boom instead of five on a 100
foot boom. On FLAT ground the antenna would probably not be as good or
versatile as a stack of 3 element yagis if you had the top one up about 200
feet. From my location this antenna should be that stack into Europe which is
80% of what I would care about for this antenna. Also, part of this is that
there are plenty of 3/3 installations and this is a much more challenging
The versatility problem will be covered with the current 3 element yagi which
will be moved to a new location on the mountain top.. To give you an example
of the terrain in one direction, the new location for the 3 element yagi at a
height of 80 feet is predicted by HFTA to be a better performer to JA than the
six element one at 135 feet. It appears to me that in some instances the only
way I can get any real advantage by phasing antennas would be for them to be
side by side instead of vertically stacked.
The supporting tower is put together laying on a few sections of 45G. There is
a small amount of work left to be done on the top section. Most of the hole
digging and concrete work has been done. All six elements have been made.
The boom is going to either be 110 feet of 45G or I have adapters to go from
45G to 25G and could have abouit 60 or 70 feet of 45G in the center and 20-25
feet of 25G on either end. Would appreciate any gut feelings on which would be
better. The boom will be put together within two weeks.
I am leaving today on a trip and will not be back for about 10 days so cannot
defend myself if attacked...:-)
The rotator is an extra large prop pitch - 102 pounder. I will use a K7NV
(Green Heron) control box and turn it at about 1/8 RPM.
I used YO and of course had to make compromises with gain, f/b and swr. Here
are the numbers. If anyone has another program and would be able to get a
little more f/b and gain without creating a funky double dip in the SWR curve
(which for some reason I cannot stand to see or deal with), I would appreciate
Here are the numbers as it currently stands:
The half element diameters and lengths are:
REF DE D1 D2 D3 D4
.50 63.25 45.75 18.125 6.5 17 6
Someone commented on the expense and using something like this to help justify
a project to the XYL. Most people justify everything they do in one way or the
other. Living in the Ozarks, where fishing is popular, I like to compare my
hobby to the fifty other guys who buy a $40,000 bass boat and go to Colorado
hunting every fall or just say you can't take it with you...
> While doing the previous simulation already with HFTA, I did another one
> for my own location on a small hilltop, which benefits from slooping
> foreground, with the same antennas.
> Here the situation is the other way round, generally the 5 element at 100?is
> better then the stack at all angles, 20db better at 1-2?, 8db better at 3?
> and 5db at 5?. They are almost part from 7 to 17? and then the 5 elements
> dominates again by 3 to 7 dbs.
> Then I had a look at other pictures of the K5UG site and saw that it is a
> hilly location as well.
> I think, I must also have a 5-Element at 100?on 40m!!
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