[TowerTalk] Choking on chokes

[Kim Elmore]

For the purpose of a choke, I used a couple of 2.4" OD ferrite toroid cores stacked as a choke-type balun for an OCFD (a Force 12 Sigma 80). I wound about 20 bifilar turns of 16 ga enameled wire on the stacked cores   It seems to work, at least at 80 m. I made a similar one for an inverted V with the center up about 40'. 

I assumed this works like a choke-type balun. Am I correct?

Kim N5OP

"People that make music together cannot be enemies, at least as long as the music lasts." -- Paul Hindemith

> On Dec 3, 2014, at 17:55, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
>> On Wed,12/3/2014 3:31 PM, Roger (K8RI) on TT wrote:
>> Take for instance the 75 meter, center fed dipole whose impedance can vary widely from well below 50 ohms to above 50 ohms depending on height.   You are feeding a supposedly balanced antenna with unbalanced line.  (Good place for a choke).
> 
> And it also varies widely from one end of the band to the other. We can see this on a Smith Chart and on an SWR curve beginning around slide #30. This particular dipole is modeled around 100 ft over average ground, and Z at resonance is 76.5 ohms. Over lousy ground, the Z would be in the mid- to high-80s of ohms.
> 
> http://k9yc.com/PacificonSmithChart.pdf
> 
> 73, Jim K9YC
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