In article ,
Charly wrote:

Telamon wrote:
[...] 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.
[...]

Another question please... Will a 2 / 6 turns balun behave the same
as a 3 / 9 turns balun ?

I suspect not, but what will be the difference ?

Snip

In a voltage type transformer the impedance and resulting
voltage/current changes are based on the ratio of the windings. The core
and number of turns in the windings change the inductance of the primary
and secondary windings and the mutual inductance between them.

You are trying to make an RF voltage type so generally shorter windings
are better so go with the minimum turns to get the ratio you want.

2/6 and 3/9 are both 1:3 winding ratio so the impedance transformation
is the same. The impedance conversion is 1:9 so 50 ohms : 450 ohms.

The mutual inductance between the windings will be greater with the 3/9.

--
Telamon
Ventura, California