[Amps] grid resonance

[Tom W8JI]

> 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).

Assuming the grid has some sort of problem based on a GDO 
meter dip is as bad as assuming a GDO can check a tank 
circuit or a  tank component like an air variable for high 
impedances (parallel resonances).

Anyway here's a sweep of 3-500Z's and 811A's.

http://www.w8ji.com/grid_resonance.htm

If you want to see tank voltage distribution in an 
SB220/221:

http://www.w8ji.com/SB221/sb-221.htm

73 Tom