Thanks Jim for your detailed response. I could have worded this better, In
the location that I roughly laid out my 4square pattern the difference
between the lowest and highest base is 5 feet. I may be able to improve the
height difference slightly moving the pattern around slightly in that
pasture. Going across the 80m 4sq diagonal, 5 ft low is only 3° out of
level. So maybe I am being overly concerned. VE9AA has 4 squares much more
out of level that that and he's happy with them plus I never had trouble
working Mike for the Sweepstakes mult. I did not consider that phased
verticals may be like Yagi's where F/B is more easily effected by system
imperfections than gain.
73
John KK9A
Jim Lux wrote:
This is where modeling can help you tell if it's a big deal or a little
deal.
The DX engineering box is a L network for phase and you have 1/4 wave
transmission lines to the elements - so that's easily doable in NEC (of any
flavor).
At first, I'd think you'll get some sort of tilt in the vertical pattern,
but
not much, and I think other factors might have a bigger effect (for
instance,
is the soil exactly the same over the entire array area).
5 feet out of 60 feet isn't a huge angle (5 degrees?).
You say you can get the height the same within 5 feet? Is that by raising
or
lowering the antenna on a post at the location? That might have a bigger
effect because it will change the feedpoint impedance, and notwithstanding
the
"current forcing" feature of 1/4 wave TLs, it does result in a change.
FWIW, you won't notice much change in forward gain with almost any
installation
imperfections. What you'll notice is that the nulls aren't where you expect
and
may not be as deep. So you need to look at *what do you expect to get out
of a
4 square".
On Mon, 7 Apr 2025 15:26:16 -0400, <john@kk9a.com> wrote:
A year ago I moved to a beautiful 17 acre property. It is all open with
lots of grass to mow. I would like to put up an 80m 4 square, I have a DX
Engineering phasing unit, controller and four freestanding verticals. The
problem is, the property slopes down from the house and it is also rolling
up and down so It is difficult to find a flat spot on higher areas for the
four verticals. To complicate matters there is a residential power line
running across the middle which seems to be on the higher spots of the
rolling terrain. The DXE manual states the base height should differ less
than 20% of the array diameter and it gives an example of 12 feet. I am
assuming array diameter means distance between verticals. I am sure that I
can get the base heights within 5 feet on a higher area of the property but
even that seems like a lot. What effect does base height have on a vertical
array? I could probably could have less base height differences if I placed
it in a valley with the 6 foot rolling hill next to and above it so the
radials would be going uphill, is that a better option? I am not interested
in elevated radials.
73,
John KK9A
http://www.kk9a.com
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