[TowerTalk] Topband: 160 meter elevated vertical

Peter Voelpel df3kv at t-online.de
Sun Oct 21 05:29:22 EDT 2012


I don´t see any reason for a common mode choke with my elevated vertical
(fed tower).
The coax screen is directly connected to the tower at the feed point and
down where the coax leaves the tower.
The inner conducter is connected to the single elevated radial.

On my 80m quarter wave with the ground radial system and underground coax I
don´t see the the need for a choke either.

73
Peter, DJ7WW

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Guy
Olinger K2AV


"Just DO the common mode choke on any vertical.  Don't tempt Murphy."

I stand by my comments.

I find after some interesting conversations that readers of posts often read
as if written to them.  So I write my posts as to the general audience.  If
an expressed situation is so specific as to be exceptional to general use, I
reply in private.

*Of course* there will be a few situations where this general purpose rule
won't add any value.  The question is whether a specific owner has the
equipment and technical knowledge to identify those situations, which are
highly specific and subject to all kinds of local influences, and whether
one can post a textbook to explain the choices.

And while theoretical situations are raised, I continue to this day finding
situation after situation where a vertical needs common mode blocking to
help fix it, and I've not ever once had to tell someone to REMOVE a common
mode choke at a vertical feedpoint.

I was speaking of vertical feedpoints.  Dipoles are another subject.

73, Guy.
_______________________________________________
Remember the PreStew coming on October 20th.  http://www.kkn.net/stew for
more info.



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