Gary Schafer wrote:
> Yes Larry, but the conclusion drawn by the one doing the experiment was that
> the current "must go thru the disk when placed in the middle". No account
> for capacitance was given.
>
> Unless I am reading this wrong the experimenter came to the wrong
> conclusion.
>
Agreed, Right results, wrong conclusion.
The disk, whether aligned with or on the edge adds two things,
capacitance and diameter to the radiator. The position makes no
difference with either.
IOW the disk appears as a lump in the diameter of the wire, but as
resonance is a summation of a whole lot of short segments the change in
diameter has little effect unless it's a short antenna.
Even with capacitance taken into account the position (edge or centered)
should make no difference.
73
Roger (K8RI)
> 73
> Gary K4FMX
>
>
>> -----Original Message-----
>> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
>> On Behalf Of Larry Benko
>> Sent: Monday, March 22, 2010 12:28 PM
>> To: Frank T Brady
>> Cc: amps@contesting.com
>> Subject: Re: [Amps] placement of RF choke bypass cap.
>>
>> Please re-read the results of the experiment. Tests #3 and #4 did
>> exactly what you are suggesting.
>>
>> Larry, W0QE
>>
>> Frank T Brady wrote:
>>
>>> Gary,
>>> Is anyone evaluating the test to account for the capacitance?
>>> I'm sure I'm not the only one fascinated by this skin effect 'proof
>>>
>> test'
>>
>>> It's beginning to sound like one of those relativity paradoxes that
>>> can't be observed without the observation changing the behavior <g>
>>> 73, frank w0ecs
>>>
>>> On 3/22/2010 12:06 PM, Gary Schafer wrote:
>>>
>>>
>>>> You are drawing a conclusion without knowing all the information
>>>>
>> needed. The
>>
>>>> disk on the antenna acts like a capacitor to the rest of the antenna.
>>>> Read a little on how an antenna works. It depends upon the
>>>>
>> capacitance
>>
>>>> between ends for return current.
>>>> Placing the disk in line only looks like a fatter element at that
>>>>
>> point
>>
>>>> which means more capacitance.
>>>>
>>>> 73
>>>> Gary k4FMX
>>>>
>>>>
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: amps-bounces@contesting.com [mailto:amps-
>>>>>
>> bounces@contesting.com]
>>
>>>>> On Behalf Of pc5m, Carel
>>>>> Sent: Sunday, March 21, 2010 1:03 PM
>>>>> To: amps@contesting.com
>>>>> Subject: Re: [Amps] placement of RF choke bypass cap.
>>>>>
>>>>> Bill,
>>>>>
>>>>> You are right !
>>>>>
>>>>> Changed my setup and to summarize the results:
>>>>>
>>>>> #1. With the disk, Fres = 480 MHz
>>>>> #2. With disk connected parallel to horizontal wire (see
>>>>> www.pc5m.com/skineffect2.jpg ). Fres = 260 MHz
>>>>> #3. With disk connected in between (no through wire at all) ( see
>>>>> www.pc5m.com/skineffect1.jpg) . Fres = 260 MHz
>>>>>
>>>>> I suppose I can only conclude that the RF current will/must go
>>>>>
>> through
>>
>>>>> the
>>>>> disk and not follow the long path (due to alleged skineffect) around
>>>>>
>> the
>>
>>>>> disk.
>>>>>
>>>>> Again a myth busted ?
>>>>>
>>>>> Gl, Carel.
>>>>> ---------------------------------------------
>>>>>
>>>>> ORIGINAL MESSAGE:
>>>>>
>>>>>
>>>>>
>>>>>> Try this: Measure the spacing from the bottom edge of the disk to
>>>>>>
>> the
>>
>>>>>> ground plane, then re-solder the disk at the edge of the disk,
>>>>>> maintaining the same spacing. Now the disk is acting as just a
>>>>>> capacitor, without having the wire's RF flowing through it.
>>>>>>
>>>>>> 73, Bill W6WRT
>>>>>>
>>>>>>
>>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>>
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>>>>
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