[TowerTalk] balun,s for 160m VERTICAL ARRAY

[jimlux]

vk3pa at vk3pa.com wrote:
> Hi all, I have some Amodon cores T300A,s, which I want to use as  
> impeadance matching netwrks for feeding my vertical array for 160m.. i  
>   would like to have the output side multi tapped inpedance eg  
> 12/29/23/30/36/40 es 50 ohms es feed line side 50 ohms..verticals are  
> 90 ft top loaded es res point is 1860khz..
> Q.is how do I WIND THESE CORES..?
> aL VK3PA
> _______________________________________________
> 

what mix are the cores?

You need ALL those impedance ratios?  That's going to be a challenge. 
The impedance ratio is (N1/N2)^2...

so a turns ratio of 2:1 makes a 4:1 transformer, 50:12.5 ohms

A ratio of 3:2 gets you 2.25:1, 50:22

You could probably put 6-10 turns for each side, and find some 
combination that gets close, but somehow, I don't think that will get 
what you're really looking for.

What's the feedpoint impedance of the antenna? 90 ft is moderately close 
to a quarter wavelength, and you say it's top loaded, so maybe your 
feedpoint impedance isn't all that far off 30-50 ohms?