[TowerTalk] choke / balun design needed

john at kk9a.com john at kk9a.com
Mon Apr 27 13:47:56 EDT 2015


Good choice abandoning the off center fed antenna plan. A dipole is a
really simple and effective antenna.

John KK9A


To:	jim at audiosystemsgroup.com
Subject:	Re: [TowerTalk] choke / balun design needed
From:	Alex Malyava <alex.k2bb at gmail.com>
Date:	Mon, 27 Apr 2015 12:50:32 -0400
List-post:

Thanks Jim,
I will read that :)

Most likely, facing the frying problem, I will go with simple dipole or
vertical delta.

On Mon, Apr 27, 2015 at 12:41 PM, Jim Brown <jim at audiosystemsgroup.com>
wrote:

> On Mon,4/27/2015 6:50 AM, Alex Malyava wrote:
>
>> What would be the bestest design for choke or balun to be used with dipole
>> or OCF dipole?
>> Like what type of core, number of turns or number of beads?
>>
>
> k9yc.com/RFI-Ham.pdf
>
> See the Choke Cookbook and text that precedes it.
>
> An off-center fed antenna is inherently poorly balanced, so it puts a high
> common mode current on the feedline, which in turn places a high common
> mode voltage across any choke. It is well known that even very good common
> mode chokes are likely to fry (fail destructively) when used with even
> moderate power levels. You MIGHT get away with it at 100W, but at some
> higher power level it WILL break.
>
> 73, Jim K9YC



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