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

[Richard Karlquist]

On 2015-02-10 14:09, Adrian Fabry wrote:

> 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.
> 

You have to be careful with loading inverted L antennas.  What is 
happening
here is that the horizontal top wire is now doing most of the radiating.
You basically have a very low dipole.  There will be a lot of ground 
loss
due to the height.  I think you would be disappointed if you built this.

Rick N6RK