[TowerTalk] Need help to select ferrites for UHF "baluns"

[Rick Karlquist]

Ferrites aren't very effective at UHF.

You probably want a coax sleeve that is 1/4 wave
on 70 cm and 3/4 wave on 23 cm, about 7 inches long.
One end of the sleeve connects to outside of shield,
the other end is floating.  Diameter is not critical.

Rick N6RK


Rob Martin wrote:
> I need to make "baluns" for 70cm and 23cm, something to thread over the
> coax to stop RF currents on the outside of the shield.
>
> I need something to go over a Type N male (ferrite ID >= 23.8mm) and
> directly over the coax (ferrite ID >= 13.8mm).