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Re: [TowerTalk] dipole length adjustment

To: towertalk@contesting.com
Subject: Re: [TowerTalk] dipole length adjustment
From: "Dan Zimmerman N3OX" <n3ox@n3ox.net>
Date: Mon, 22 Jan 2007 14:33:46 -0500
List-post: <mailto:towertalk@contesting.com>
Jim Lux suggests:

>For instance, you could take the existing tuner Bud is using, put it
>in a weather proof enclosure, add some servos or steppers, etc.  But
>that's probably more of a pain than just running the openwire line.

I dunno, that's what I did.  Granted, I had a balcony with a roof to
limit the amout of weatherproofing that I had to do, but the servo
thing was cheap and fairly reliable, even though it was a pretty ugly
hack the first time.  In my case, I had to run all feedlines out under
the balcony door so ladderline wasn't an option.  (And yes, I had
noticeable feedline loss on some bands with coax, even with a 20' run
!!)

http://www.n3ox.net/projects/servo

I've upgraded my technique a bit for an antenna that doesn't change so
much.  Having the T-match tuner was very useful when I was shooting
random lengths of magnet wires into trees to replace the ones that
break.  I decided I liked fast band switching better than ease of
initial setup and came up with the matching for this:

http://www.n3ox.net/projects/sixtyvert

The latter one is probably *not* good to 1500W on all bands just
because I was using a smallish wafer switch and haven't bothered to
check component ratings, because I just run 100W.  Still, it would be
a snap to size everything for 1500W.  Not cheap.

My 80m networks would probably take full legal limit with a switch
upgrade.  40m might but I don't know what my cap is good for,
voltagewise, and it's an end-fed near-halfwave.

Cecil's ladderline approach is good too, and if you're already
thinking ladderline, it's easy to implement.

73,
Dan
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