[TowerTalk] Choking on chokes

[Herbert Schoenbohm]

I have always wondered ......... since I have acquired six of those 
square snap on ferrite blocks if they would provide any sufficient 
chocking action on my 12 meter or 6 meter beam coax feeds as the fit 
perfectly on LMR 400 or 9913?   If they are of any value what would be 
the recommended spacing on the coax starting at the feed point?


Herb Schoenbohm, KV4FZ



On 12/3/2014 10:50 PM, Kim Elmore wrote:
> 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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