🚀 go-pugleaf

John Devereux wrote:
> RFI-EMI-GUY <Rhyolite@NETTALLY.COM> writes:
> 
>> David L. Jones wrote:
>>> notme wrote:
>>>> On Sun, 26 Jul 2009 05:22:31 -0700, David L. Jones wrote
>>>> (in article <%TXam.45224$3m2.4738@newsfe06.iad>):
>>>>
>>>>> http://www.edn.com/blog/1700000170/post/1120046912.html
>>>> So, it's not a phenomenon of that scope, but an example of how long
>>>> ground clips can get you into trouble at high frequencies, regardless
>>>> the tool at the other end of the probe.
>>> Nothing to do with the long clip lead on the end, as I
>>> demonstrated. Regular issues with long ground clips at high
>>> frequency is another problem entirely.
>>> You can have the best and shortest ground clip possible and you'll
>>> still get this effect, picked up by the probe coax.
>>> And the latest video shows you don't even need the cable connected
>>> at all to get a response.
>>>
>>> Enjoy.
>>> Dave.
>> Try with an older analog scope with a metal cabinet. I think you have
>> uncovered a shielding weakness with the newer digital scopes. The
>> resonant frequency is probably coincidental with the internal
>> circuitry or groundplane geometry of the scope
> 
> I was thinking that. The IEEE standard for characterising ESD pulse
> generators requires the whole scope to be put in a Faraday cage.
> 
> 

It is possible that even an older style CRT scope might be susceptible 
given the opening for the CRT screen might be a sufficient aperture for 
the ESD pulse.

-- 
Joe Leikhim K4SAT
"The RFI-EMI-GUY"�

"Use only Genuine Interocitor Parts" Tom Servo  ;-P