[TowerTalk] How to calculate aluminium transmission line impedance?

[David Gilbert]

That sounds like the feed system on my OB16-3.  I once looked up the 
formula for that and it came out roughly 100 ohms.  When I used that in 
the EZNEC model I got almost identical results to the plots for both 
pattern and SWR that I got from Tom when I bought the antenna.

73,
Dave   AB7E



On 10/9/2022 7:17 PM, Tonno Vahk wrote:
> Hi,
>
> I have EZNEC model of a tribander with one feedpoint where 10-15-20m elements are joined with a transmission line of 20mm x 20mm aluminium profiles, the gap between the profiles is 15mm.
>
> For the model I need to know the impedance of the transmission line.
>
> EZNEC provides a tool to calculate it from the wire diameter and spacing. Is there any correction that should be applied with square aluminium bars? How to calculate the correct impedance in this case?
>
> In ENZEC model I have Length = Actual Distance, VF = 1. And the only thing missing is the Zo I believe.
>
> Look, forward to learn how this is calculated:)
>
>
> 73
> Tonno
> ES5TV
>
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