Re: LF: Re: Drooping top loading

["Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>]

John, G4CNN, did some extensive calculations on drooping toploads
(umbrella antennas). A summary of his work and a link to the webpage with
all info can be found at :
http://www.qsl.net/on7yd/136ant.htm#Umbrella

73, Rik  ON7YD

At 12:16 22/10/2002 +0200, you wrote:
> To All from PA0SE
>
> In order to find  the effect of drooping top load wires upon the
> radiation resistance I modelled an umbrella antenna using K6STI's antenna
> simulation program Antenna Optimizer.
>
> The antenna modelled consists of a vertical wire of 10 m with at the top
> four wires of 10 m each in the directions N, E, S and W.  The wires
> include an angle of alpha degrees with the horizontal.  All wires
> have a diameter of 1.5 millimetres.  The antenna is erected over
> perfect ground.
>
> Alpha        
> Rrad      Capacitance
> (degrees)  (mohm)      (pF)
>
>  0                       
> 26                  
> 256   (horizontal top wires)
>
> 20                      
> 18                  
> 254
>
> 40                      
> 12                  
> 250
>
> 60                        
> 8                  
> 237
>
> 80                        
> 8                  
> 175  
>
> 73, Dick, PA0SE
> JO22GD