Topband: High-Power Unun Components?

[K9AY]

> What characteristics of a unun determine its power-
> handling limits?
>
> I am interested in the case of matching a 160 meter
> inv-L with good ground (1.5:1 unun), for 1.5 KW with
> a safety margin: perhaps a 2+ KW continuous rating.
> This is a single-band application: only 160 meters.

>K8ND
_______

Jeff,

I agree with K6XK that an unun is probably not the best solution for a 
single-band application -- A shunt coil or shunt capacitor will work as well 
and only need a single component. An L-network would allow you to adjust the 
matching without the need for pruning the wire.

As to your original question, winding technique and core material are the 
key factors that determine loss in all ferrite transformers. You need the 
right number of turns (choking inductance) with wires that have the right 
characteristic impedance, and you need a core with both the correct 
permeability and resistivity, as well as sufficient bulk for the expected 
power dissipation.

73, Gary
K9AY