In article ,
Charly wrote:

Good morning Telamon,

Telamon wrote:
The impedance ratio of your transformer is 50 ohms to 800 ohms.

p= primary
s=secondary

Turns p/Turns s = the square root of (impedance p / impedance s)
so
2/8= square root(50/s)
800 = s

The turns ratio is 1:4 and the impedance ratio is 1:16. In other words
the impedance ratio is the square of the turns ratio. This is a little
high and I would go for more like turns ratio 1:3 for impedance ratio
of 1:9, which would be 50 ohms : 450 ohms. For example you could use 3
turns primary and 9 turns secondary.

Thanks for the formula...

The sloping wire characteristic impedance will change with the height
above ground so I expect that you would want an impedance number at the
coax/wire junction.

You mean that the impedance of the core will depend on its altitude ?

Snip

The impedance of the wire will change with its height above ground. You
are trying to transform that impedance to that of the coax.

Basically the higher the wire the higher the impedance. Smaller diameter
wire for the same height will be higher in impedance.

--
Telamon
Ventura, California