[TowerTalk] current balun question

[Jim Brown]

Hi Svend,

Yes. Use a lot of #43 clamp-on cores. Buy the longest ones that fit the 
cable. Study the data sheet and aim for at least 1K ohms. More is better. :)

On Tue,3/14/2017 11:08 AM, Svend Spanget wrote:
> Hi Jim.
> Do you have a recommendation for an effektive choke for 144 MHz?
>
> VY 73 de Svend, OZ7UV
>
> Den 14. mar. 2017 18.19 skrev "Jim Brown" <jim at audiosystemsgroup.com 
> <mailto:jim at audiosystemsgroup.com>>:
>
>     On Tue,3/14/2017 12:41 AM, Máximo EA1DDO_HK1H wrote:
>
>         Same question in a different way is; Is the current choke
>         forcing to balance differential currents?
>
>
>     Hello Maximo,
>
>     An effective common mode choke forces current to near zero at the
>     point where it is placed. IF it placed at the feedpoint, it will
>     force current in the sides of the antenna to be equal AT THE
>     FEEDPOINT. In effect, it disconnects the feedline from the antenna
>     as an element of the antenna.
>
>     If the same choke is placed near the shack, the feedline IS part
>     of the antenna, with it's electrical length equal to its physical
>     length, with the choke forcing the common mode current to near
>     zero at the point where it is placed in the feedline.
>
>     By "effective," I mean a choke that has a very high common mode
>     resistive impedance at the operating frequency.
>
>     73, Jim K9YC
>
>
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