[TowerTalk] Choke on feed point of dipole

[Ken WA8JXM]

How are  you determining that the resonance shafted down?

Ken WA8JXM

On Mon, Jan 12, 2026 at 1:50 PM Tom Hellem <tom.hellem at gmail.com> wrote:

> TT'ers:
>
> I made a choke to place at the feed point of a 20 meter vertical dipole.
> 9 turns of #14 thhn wound on a 2.4" mix 31 ferrite toroid.
> After I installed the choke, the resonant frequency appears to have
> moved approx. 1 mhz lower.
>
> Is this the behavior I should be seeing?
> I've used plenty of chokes on yagis, etc and never noticed this
> before.
>
> Modeling in Eznec shows that changing the ground constants
> does not appreciably change the resonance, so it seems that the fact  the
> ground getting wetter between the two measurements would not
> be the cause.
>
> Any ideas?
>
> Tom
> K0SN
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