I typically use the whole stack of antennas all the time unless I am
pointing in multiple directions. I have all individual rotators, some
people with rotating towers add a rotator to one of the antennas and
somehow calculate its direction.
I have BOP on my 40m beams and I would not buy it again. I operate mostly
DX contests where BIP is always better but even for an occasional domestic
contest I never use it. It rarely improves the signal and I think I
benefit more in domestic contests by spraying two directions.
John KK9A - W4AAA
To: <towertalk@contesting.com>
Subject: [TowerTalk] 20m stack switching question
From: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 13 Jul 2016 09:27:13 -0700
A buddy has 3 x 20m monobanders, stacked at 172, 117, 62 ft.
Currently,
Ok, is it even worth it to be able to use any 2 yagis ?? For DX, all 3 in
phase work pretty good. For local, say within 3000 miles, perhaps
the lowest yagi alone would suffice? I cant see the top and bottom
buying
him anything..... vs all 3 in phase. I cant see the top and middle
outperforming all 3 in phase. That only leaves the middle and bottom..and
even that is dubious... but we have zero experience with this.
Are we wasting our time ? On a side note, the pair of 40m yagis, 180 + 89
feet, are also driven in phase.... with no provisions for top + bottom
switching. However, BOP was added to the BIP. Easily done with a
switchable 1/2 wave of coax in either leg. Then countless hrs spent
switching between
BIP...and BOP. BOP was a disaster. Only once was BOP a bit louder... and
that was on 40M during the daytime..and just one station, aprx 200 miles
away.
Looking at some notes here and there, it appears that BOP has a higher take
off angle than the lower 40M by itself...which ends up way too high.
Latest plan is to be able to switch top /bottom /both on the pair of 40m
yagis......and ditto with the pair of 15M yagis ( 127 + 79 ft) . We could
also add
the BOP function, but after the 40M failed experiment, I think BOP is a total
write off.
Any thought on any of this would be greatly appreciated. BTW, all yagis
are
pointed in the same direction on a rotating tower.
Jim VE7RF
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