On 10/20/20 10:49 AM, Jim Brown wrote:
On 10/20/2020 9:42 AM, k7lxc--- via TowerTalk wrote:
So what other manufacturers of vertical dipoles would be worth doing
business with?
Certainly those that you and N0AX tested 2o years ago. Like any
vertical, their performance will depend on soil conductivity, and they
will work a bit better if roof mounted.
I think though, Steve LXC was interest in vertical dipoles (recognizing
that some multiband verticals are quasi dipoles, albeit with very
unequal lengths).
Isn't the GAP vertical series also a vertical dipole (off center fed)?
Except that the Greyline depends on having a tuner/matching network at
the bottom to deal with the mismatch.
Essentially, it seems this no different conceptually than an
electrically short horizontal dipole with a tuner at the feedpoint -
with modern tuners, etc., I think this is pretty viable. You make the
dipole short enough that you don't get weird high order lobes (like you
would with, say, a 40 foot vertical against a groundplane or radials on
10 meter band).
Most of the commentary on the various forums seems more about the
business practices than the actual antenna design. Maybe it's a "you
can't get there from here for that price" kind of scenario.
It's complicated, supply chain-wise, by the fact that the matching
network is an integral part of the system - it's not a "go get aluminum
tubing, cut to size, add bracketry and make the kit".
I think also, without much information, that the idea of essentially
converting a flagpole design is a clever one. And one that could be done
by anyone - You make a deal with a flagpole manufacturer to either build
it with the insulators & holes in the right places, or you do that as a
modification step.
Just browsing through the Home Depot website, for instance, you can find
a 20 ft aluminum flag pole for $150.
But you go to commercial flagpoles and a 30 footer is a bit pricier.
Upwards of $600. Sectional poles (which I assume come in smaller
lengths that you assemble, which might be better for antenna use) are in
that bucket for a 25 footer.
https://www.united-states-flag.com/commercial-grade-sectional-25-ft-flagpole-satin.html.
says good to 69 mi/hr without a flag.
It doesn't give any information on the lengths of the segments, but you
could probably figure it out.
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