Topband: Top Loaded Vertical

[k8gg at voyager.net]

Charlie, K4UWH wrote:

> I have an aluminum vertical element
that is 67' tall. I want to top-load 
> it 
> on 160
meters and would like to use a three wire approach for physical 
>
symmetry in support of the vertical element. Does anyone have an idea of

> about how long the three wire elements would need to be to
top-load it for 
> 160? I was guessing about 40' but that was a
wild guess. It would be 
> nice 
> to know approximately
where to start if anyone has had similar experience. 
> Thanks
K4UWH 

Charlie, et. al.

Attaching 3 wires each
40 foot long at the top of your 67 foot vertical could bring the resonant
frequency close to 1830 KHz.  The actual frequency
will depend on the angle at which the top loading wires slope
down from the top of the vertical.    It will
also depend on the diameter of the wires used, and the sizes of the tube
sections used to construct the 67 foot vertical.  The feed point
impedance could be as low as 18 ohms with a good ground radial
system.  

In any case I think you picked a good
starting point for the 3 top loading wires.

73 &
GL         
George           K8GG