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Re: Topband: inverted L antenna match system

To: topband@contesting.com
Subject: Re: Topband: inverted L antenna match system
From: Mike Waters W0BTU <mrscience65704@yahoo.com>
Date: Fri, 28 May 2010 13:12:04 -0700 (PDT)
List-post: <topband@contesting.com">mailto:topband@contesting.com>
> From: sasas asasas <tzitzikas_ee@yahoo.com>
> Subject: Topband: inverted L antenna match system
> ... My antenna is an inverted L
> with length = [5*(wave length)]/16. I read at ARRL handbook
> that a variable series capacitor 0-1000pf is enough to
> match the transmitter with my antenna. What do you think
> about this? ...

The formula you provide above calculates to a total length of your inverted-L 
of 50 meters (164 feet), if wave length=160.

My 150 foot inverted-L (vertical portion is 50 feet) has the following matching 
arrangement to reduce the SWR to 1:1 at the feedpoint:

approx. 350 pf series capacitor from coax center conductor to Inv-L
approx. 200 pf parallel capacitor from Inv-L(and 300 pf cap.) to ground radials.

No coils were required in my case. Both capacitors are air variables,

No ground rod was used. Coax choke at feedpoint.

Hope this helps. Your results may vary.

73 Mike


      
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