Re: [TCML] Quick Question

[Gary Lau <glau1024@xxxxxxxxx>]

>  Not really sure how much good they do, but they can't hurt,

Not sure that's a safe assumption.  RF chokes were at one time considered a
useful component in NST protection circuits until thoughtful PSpice
simulations showed that new resonances actually made things much worse.
 Also, "big" coils of wire suggest the possibility of significant resistive
losses - something you don't want in your tank circuit.

> and they look cool.

Well I'll give you that!

Regards, Gary Lau
MA, USA

On Tue, Jul 9, 2013 at 10:46 AM, Carl Noggle <cn@xxxxx> wrote:

> Also, you can make RF chokes with big solenoids of stiff wire.  Not really
> sure how much good they do, but they can't hurt, and they look cool.  And
> I've never burned anything out.  (Kind of disappointing, in a way, if you
> know what I mean.)
>
> ---Carl
>
>
>
>
>
> -----Original Message----- From: Jim
> Sent: Monday, July 08, 2013 4:45 PM
> To: tesla@xxxxxxxxxx
> Subject: Re: [TCML] Quick Question
>
>
> Almost reminds me of twisted pair.
>
> On 7/8/2013 9:18 AM, Jim Lux wrote:
>
>> On 7/8/13 1:04 AM, Jim wrote:
>>
>>> FWIW, I met an engineer who told me that the spark gaps are what create
>>> all of the emi. He said when they fire they cover infinite frequencies.
>>>
>>>
>> well, not infinitely..
>>
>> The fast rise time when the gap fires does create a very wide band of
>> frequencies.  However, not all of them are radiated equally. Terry
>> Fritz made some radiated RF measurements on a spark gap coil with a
>> spectrum analyzer and my fuzzy recollection is that he found the
>> (broad) peak in the spectrum had a frequency that depended on the
>> length of the wires (all up in VHF spectrum).
>>
>> This makes sense, the gap is basically at the feedpoint of an
>> improvised dipole antenna with a bunch of weird stuff at the end of
>> the dipole.
>>
>> There was some discussion about whether suitable ferrites could knock
>> this down, but there are a lot of tricky aspects to that. You don't
>> want to be slapping some number 43 mix beads on the HV gap wires
>> randomly.
>>
>> If it is "radiating" from the gap wires, then running the wires to and
>> from the gap next to each other (suitably insulated) will greatly
>> reduce the radiation.
>>
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>>
>
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>
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>
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>
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