An UN-UN is un balanced to unbalanced. Is that what you have ? A vertical
is unbalanced. Willy
In a message dated 5/30/2015 12:02:54 P.M. Eastern Daylight Time,
topband-request@contesting.com writes:
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Today's Topics:
1. vertical balun (Bob Kupps via Topband)
2. Re: vertical balun (shristov)
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Message: 1
Date: Fri, 29 May 2015 21:13:50 -0700
From: Bob Kupps via Topband <topband@contesting.com>
To: topband <topband@contesting.com>
Subject: Topband: vertical balun
Message-ID:
<1432959230.96755.YahooMailBasic@web125001.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=us-ascii
Hi we have a 30m top loaded monopole with the feed point about 2m above a
large ground radial field. Right now we are feeding it through a 4:1 balun
(not a unun) with 12.5 ohms on the balanced side, and the SWR is 1.4 with
no matching network. Is this balun acting as a common mode choke? Do we even
need a choke? Would an unun be better?
Thanks 73 Bob HS0ZIA
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Message: 2
Date: Sat, 30 May 2015 06:40:14 +0200
From: shristov <shristov@ptt.rs>
To: topband <topband@contesting.com>
Subject: Re: Topband: vertical balun
Message-ID: <fb2e9fb35082.55695b4e@ptt.rs>
Content-Type: text/plain; charset=us-ascii
Bob Kupps wrote:
> Right now we are feeding it through a 4:1 balun (not a unun) with 12.5
ohms on the
> balanced side, and the SWR is 1.4 with no matching network.
You should get quite a reasonable SWR with no matching at all.
A good high-impedance common mode choke is recommended.
73,
Sinisa YT1NT, VE3EA
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