> One thing that I've never seen mentioned anywhere is a
multiple-band dipole fed with ladder line. The reason I'm
curious about it is that I used to have an 80-Meter Inverted
Vee fed with ladder line, and the performance was great on
80M. For 160M contests, etc. I would add about 65 feet to
each leg so that it became a full-sized Inverted Vee for
160. However, in doing that, even though the tuner matched
it just fine on 80M, my great 80-Meter performance went away
until I removed the 160M extensions. I always wondered if I
could have had both, if I had built up a combination 160 and
80M Inverted vee with both sets of elements off of the same
ladder line feeder, like may people do with coax-fed
multiple dipoles. Anyone ever try something like this?
>
> LJ
>
>
>
>
> -----Original Message-----
> From: Keith Dutson <kdutson@sbcglobal.net>
> Sent: Jun 28, 2005 8:11 AM
> To: TowerTalk <towertalk@contesting.com>
> Subject: Re: [TowerTalk] Improving my dipole
>
> I would hang the dipole with extra wire pointing down
instead of in the
> trees. IOW, move the suspension line on both ends toward
the center. There
> is little current at the ends. Keep the ladder line
(light weight, low
> loss) and run all the way to the shack entrance. Use a
current balun there
> (under eave usually best location) for coax changeover, or
just keep the
> same connection you have but form an RF choke using about
8 turns of coax on
> a 1 foot diameter.
>
> 73, Keith NM5G
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Art
Boyars
> Sent: Monday, June 27, 2005 8:34 PM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Improving my dipole
>
> On the CQ-Contest Reflector K7QQ said: "You have to keep
in mind that the
> best antenna doesn't exist. You can only get up what you
can and it is never
> enough." Well that's where I am, but I'd like advice from
you experts on
> how to improve my antenna, within my personal constraints.
>
> My antenna is a dipole, about 99-ft long, strung between
maple trees of the
> neighbors on either side. (It's already much higher than
the peak of my
> roof. No other supports available.) The feed line is
mostly window-pane
> twin lead, with several feet of coax to get into the house
and reach the
> Transmatch. Yeah, I know it's not balanced; but should I
really care, as
> long as the RF goes somewhere other than losses? (And I
know that the high
> SWR might cause the coax to arc over or have noticeable
resistive loss, but
> that's one of the constraints -- for now.) My main
operating interest is SS
> CW, with a little other casual contesting (work the Club
members and the big
> guns) and a bit of 40M CW DXing (if I can get the antenna
to work better).
>
> I've pulled the ends of the dipole as far as I can into
the trees (maybe too
> far), but it still sags quite a bit -- 5 to 10 feet, by
eye. Some of the
> sag is probably from the weight of the antenna wire and
the feedline, but I
> think a lot of it is simply from the dipole's being longer
than the span
> between the trees.
>
> I have two seat-of-the-pants concerns. First, I may be
getting losses from
> having the ends of the dipole in the foliage. Second, the
vertical-V might
> be more NVIS-like than Iis good for me. Obvious solution
is to shorten the
> dipole a bit, but that would make it even shorter than the
recommended
> 100-ft minimum. So, first question for the experts: Do
you think I'll do
> better to shorten it, or should I leave the ends in the
trees?
>
> Second-order solution and question: If it turns out that
the feed line is
> weighing down the center, would I be better off to let it
sag than to change
> to something more like TV twin-lead? (I recall some
discussion here about
> Radio Shack selling a twin-lead with heavier-than-typical
conductors.)
>
>
> Thanks for your help.
>
> 73, Art K3KU
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting
Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free,
1-800-333-9041 with any
> questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting
Towers", "Wireless Weather Stations", and lot's more. Call
Toll Free, 1-800-333-9041 with any questions and ask for
Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting
Towers", "Wireless Weather Stations", and lot's more. Call
Toll Free, 1-800-333-9041 with any questions and ask for
Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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