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:w6...@me.com] Sent: Wednesday, February 11, 2015 2:30 AM To: Adrian Fabry Cc: topband@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 <yo2...@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 > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband