That's how I did it, trial and error to see what worked for me. I'm not 
saying it's right, or anything I do is right, but it works, and that's half 
the battle.
----- Original Message ----- 
From: "T Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, June 05, 2008 4:42 PM
Subject: Re: correctly using Radio Shack RF chokes


>    Steve:
>
> You can correct this tired old professor any time!  (grin)
>
> If I was a professor who knew everything, I'd be making way more money 
> than
> I am now, and probably would be running some d x pedition station from 
> some
> exotic island somewhere.  (grin)
>
> Thanks for the clarification on the cores.
>
> From what I'm gathering on the list, there are several different theories 
> as
> to actually how to wind the wire, so I'll just have to do some trial and
> error here, and see what works.
>
> Thanks as always for your very helpful responses to this question, and the
> various other  questions I've asked over the years.
>
> 73 from Tom Behler:  KB8TYJ
>
> ----- Original Message ----- 
> From: "Steve Forst" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, June 05, 2008 4:05 PM
> Subject: Re: correctly using Radio Shack RF chokes
>
>
>> Hi Tom,
>>
>> Not wanting to correct the professor, but for what it's worth,  they are
>> not
>> magnets, although they  have magnetic properties.  They are made of
>> ferrite,
>> which is  a ceramic that has iron mixed in.  As someone said there are
>> various "mixes" which  would have  differing properties  suitable for
>> different frequencies.  You would need to worry about the different mixes
>> if
>> you were building a balun  and needed to cover a particular freq.
>> Shouldn't
>> be a big deal when doing rfi stuff.
>>
>> You are doing it correct.  I don't understand the math behind it, but
>> every
>> turn of the wire through the core increases the choking by  the square
>> root
>> of something or other, so the more turns the better.
>>
>> Other (cheaper) sources besides RS are Amidon, and Fair-rite.  Another
>> source I've used is:
>>
>> http://www.allelectronics.com/make-a-store/category/235/Ferrites/1.html
>>
>> These are slightly different, in that  you open the plastic clamshell and
>> lay the wire in like putting a hot dog in a bun and then close the 
>> plastic
>> shell.   Different sizes for different cables, or use a larger size and
>> wind
>> the cable several times.
>>
>> When running 600 watts on 160 I was getting some  sounds from the 
>> internal
>> keyer in my headphones, while not using that keyer.   Some trial and 
>> error
>> and found that clamping  one on the 12 v  line from power supply to rig
>> cured it.
>>
>> 73, good luck Steve KW3A
>>
>>
>>
>> ----- Original Message ----- 
>> From: "T Behler" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Thursday, June 05, 2008 2:07 PM
>> Subject: correctly using Radio Shack RF chokes
>>
>>
>>> Hi, all.
>>>
>>> This is probably self evident, and maybe I've done it the only way
>>> possible,
>>> but could someone tell me how to most effectively use the rectangular
>>> Radio
>>> Shack RF chokes for dealing with RFI?
>>>
>>> I guess I'm asking this question basically because my strategy doesn't
>>> seem
>>> to get any results whenever I try it.
>>>
>>> What I do is open the top of the choke, wind the wire through the bottom
>>> of
>>> the choke, and then close it up again.
>>>
>>> If there's some other way to use these chokes, please enlighten this
>>> sometimes slow learner.  (grinning widely here)
>>>
>>> If you don't recall what the Radio Shack RF chokes are like, they are
>>> rectangular in shape, with magnets on the inside.  You open the latch on
>>> the
>>> top, and then close it when you're done winding wires around it.
>>>
>>> Hope this somewhat convoluted e-mail makes sense.
>>>
>>> 73 from Tom Behler:  KB8TYJ
>>>
>>
>