Topband: Inverted-L with coil on the top of the vertical section

[Adrian Fabry]

Hi James,

Thank you for the hint. I read the article, and I see t's a very good
solution. For the moment I can't install this elevated FCP.

I have to mention my soil is good, quite wet most of the winter.

73 Ady YO2NAA

-----Original Message-----
From: James Bennett [mailto:w6jhb at me.com] 
Sent: Wednesday, February 11, 2015 2:30 AM
To: Adrian Fabry
Cc: topband at contesting.com
Subject: Re: Topband: Inverted-L with coil on the top of the vertical
section

Ady - you might consider using a Folded CounterPoise, designed by K2AV, for
your "radial" system. I have one on each of my Inverted L antennas; 160 & 80
meters. They work quite well if you do not have the real estate for a lot of
radial wires. My 160 Inverted L only goes up 35-40 feet bit with the FCP it
performs very well. 




> On Feb 10, 2015, at 2:09 PM, Adrian Fabry <yo2naa at gmail.com> wrote:
> 
> Hello all,
> 
> 
> 
> I'd like to build an Inverted-L antenna. Unfortunately the vertical
section
> will be only 8m (26 ft) high and the radial system not great (maybe 5 to
10
> wires laying on the ground)
> 
> The simulation (with MMANA software) indicate 3.5 +j0 Ohm impedance. This
is
> very low so I think most of the power will be lost in the ground. 
> 
> In order to raise the impedance, I would insert a coil (about 75 uH) on
the
> top of the vertical section and restore the resonance with 48.7 pF series
> capacitor on the feed point. 
> 
> This will raise the impedance to 34 ohm. 
> 
> 
> 
> Is this solution OK? Should I better place the coil at the feed point ?
> 
> 
> 
> I know it would be much better to increase the height of the vertical
> section and to install more radials or a ground screen, but this is not
> possible for the moment, so I have to find the best compromise.
> 
> 
> 
> 
> 
> Thanks for reading.
> 
> 
> 
> 73 Ady YO2NAA
> 
> _________________
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