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Topband: End Fed Twin Lead Marconi Antenna

To: <Topband@contesting.com>
Subject: Topband: End Fed Twin Lead Marconi Antenna
From: "Lee K7TJR" <k7tjr@msn.com>
Date: Tue, 4 Mar 2008 18:43:18 -0800
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Steve said,  Is the UNUN approach better or 
worse or about the same as the reactive antenna with series capacitor 
approach?  

I think the answer to your question depends entirely on the quality of your 
unun or matching components. I have a 25+J0 vertical that is matched with a 
coil and capacitor. The coil is optimized for Q by using proper dimensioning. 
The capacitor is an old (WW2 surplus) transmitting mica of 2000pf. I have 
checked this matching unit for any temperature rise after running 1Kw plus for 
hours in contests. It wont even melt the snow around it. No detectable 
temperature rise at all which should mean LOW losses. I have not tried ferrites 
in this application but in other applications have seen temperature rises from 
their losses. The unun specs should be revealing.  As always YMMV  
 Lee K7TJR Oregon
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