Well, for instance, I just bought a Big SteppIR vertical. The company
recommends a balun in some cases. They said it was to keep the RF from
coming down the coax. They also sell this balun. Not being a purist, I often
like to use the term balun meaning an RF choke as well as a 1:1 matching
device. Balanced to unbalanced.
I normally just use a string of large ferrite beads at the feed point. I
haven't modeled this with EZNEC yet, but I would bet that the radials will
couple some RF to the coax shield, hence my question as to where to place
the beads, balun, or whatever one wants to call it.
Best regards,
Tom W0HH
----- Original Message -----
From: "Jan Erik Holm" <sm2ekm@telia.com>
To: <towertalk@contesting.com>
Sent: Thursday, December 18, 2003 10:45 PM
Subject: Re: [TowerTalk] Vertical balun
> Why a balun?
>
> 73 Jim SM2EKM
> --------------
>
> Don Havlicek wrote:
> > Tom,
> > Good question!
> > I never used a balun on the 80m vertical, but might when I replace the
> > coax this Spring.
> > I'll be interested in reading the responses to your query.
> > Don
> > N8DE
> >
> > Tom Champlin wrote:
> >
> >> The recent discussion of ground radials has been a big help for me.
> >> There is just one other thing that bothers me. Most hams would
> >> probably either run buried PVC to put the feed line in, which would of
> >> necessity be parallel with the nearest buried radials. Even if
> >> everything was above ground, my question would be the same. Assuming
> >> it would be desirable to use some kind of balun on the coax before or
> >> at the vertical feed point, possibly a W1JR toroid type, or some
> >> ferrite beads. The object being to keep RF from running back to the
> >> shack on the coax braid.
> >> So, would one want to place this balun past the radial field but
> >> before the feed line gets close to the house or right at the antenna,
> >> or does it matter?
> >> Tom W0HH
> >> _______________________________________________
> >>
> >> 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
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> >> 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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