[Amps] grid resonance

[R L Measures]

On Aug 7, 2006, at 1:42 PM, Tom W8JI wrote:

>> Now here is the biggie that caused this thread....is the
>> grid on a 3-500Z
>> physically large enough to fall into "significant
>> electromagnetic
>> interaction" category, or is it in the "hard-wired"
>> category, or none of the
>> above?
>
> Of course it is large enough to have resonances at
> frequencies we might be interested in. We not only have to
> contend with lead lengths there is also considerable
> capacitance, both distributed and lumped at points (like
> that big grid support cone).

When the grid is grounded, isn't the grid support cone grounded, Tom?
>
> Assuming the grid has some sort of problem based on a GDO
> meter dip is as bad as ... ...

Ignoring a resonance is good engineering practice?
>
> Anyway here's a sweep of 3-500Z's and 811A's.
>
> http://www.w8ji.com/grid_resonance.htm

So the 3-500Z has a grid resonance at 95MHz.  Curiously, this happens  
to be the frequency of the intermittent parasitic oscillation in the  
Henry 2K-4A.
>
> If you want to see tank voltage distribution in an
> SB220/221:

I thought we were talking about grid resonance.
>
> http://www.w8ji.com/SB221/sb-221.htm
>
> 73 Tom
>
>
>
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R L MEASURES, AG6K. 805-386-3734
r at somis.org