[Elecraft] K3 & S9 43' Vertical

[Guy Olinger K2AV]

The trick is that a match to 43' on 160 must be its own setting, and the
same taps CANNOT be used for both 160 and 80. AND as you specify the
matching toroid device MUST be at the base of the antenna.  Please not the
toroid is NOT wired as a balun, but is really a tuned transformer, where the
very large capacitive reactance of the antenna on 80 and 160 is tuned out by
the selection of the top taps, and the step down impedance by the selection
of the mid taps. At the tuned frequencies, the coax is MATCHED and not
subject to the worrisome (and accurate) loss graph on the VK1OD site.

With a DPDT relay to select top and mid taps, AND with "dense" on/in-ground
radials, this becomes an elegantly simple and efficient short antenna for a
somewhat narrow single band of frequencies on 80 and 160.  The efficiency
WILL go down as you move away from the tuned frequencies, and if your
operating habits cover all of 3.5-4 and 1.8-2, you should invest in the auto
tuner at the base and resign yourself to not running 1500 watts, unless you
have the smackers to invest in one of those military KW CCS matchers.

Phil's solution WILL handle 1500 watts at the selected 80/160 tuned
frequencies. And the T400-A2
will not be smoked.

73, Guy.

On Tue, Mar 22, 2011 at 1:14 PM, Paul Christensen <w9ac at arrl.net> wrote:

> In addition to AD5X's excellent work, anyone considering installation of a
> 43' vertical should first read Owen Duffy's (VK1OD) well-researched
> information, especially his information concerning feed-point alternatives:
>
> http://vk1od.net/antenna/multibandunloadedvertical/index.htm
>
> One reason for the 43' vertical's popularity is that typical radiation
> resistance is better than 100 ohms on 40m-10m -- but falls to less than 10
> ohms on 80m and much lower on 160m. On 160m/80m, system losses typically
> drop nearly in half with an ATU placed at the base feed when compared to a
> 4:1 current balun feed with ATU at the transmitter.
>
> Paul, W9AC
>
> ----- Original Message -----
> From: "Julius Fazekas n2wn" <phriendly1 at yahoo.com>
> To: <elecraft at mailman.qth.net>
> Sent: Tuesday, March 22, 2011 12:51 PM
> Subject: Re: [Elecraft] K3 & S9 43' Vertical
>
>
> > Hi Tom,
> >
> > Check out Phil's, AD5X, site: http://www.ad5x.com/articles.htm
> >
> > He has written a number of articles related to your questions. Good
> > information with plenty of "how to" ideas with locally found materials.
> >
> > Elecraft's Balun kit is also capable of 1:4 unun and will easily work
> with
> > any 100 watt rig.
> >
> > QST has had several items related to the ubiquitous 43' verticals that
> are
> > all the rage now. I see at least one person has mentioned radials, which
> > are
> > a must have to effectively use this antenna on 80-30.
> >
> > The K3's ATU is very effective, but keep in mind that you will be
> matching
> > the feedline and antenna as a unit, versus matching just the antenna. The
> > K3
> > will most likely find a match most of the time, but you still could be
> > seriously mismatched at the antenna. It may work, it just won't work
> well.
> >
> > GL es 73,
> > Julius
> >
> > -----
> > Julius Fazekas
> > N2WN
> >
> > Tennessee Contest Group
> > http://www.k4ro.net/tcg/index.html
> >
> > Tennessee QSO Party
> > http://www.tnqp.org/
> >
> > Elecraft K2        #4455
> > Elecraft K3/100 #366
> > Elecraft K3/100 #1875
> > --
> > View this message in context:
> >
> http://elecraft.365791.n2.nabble.com/K3-S9-43-Vertical-tp6193993p6197137.html
> > Sent from the Elecraft mailing list archive at Nabble.com.
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