[Amps] grid resonance

[Ian White GM3SEK]

Phil Clements wrote:
>
>> But that resonance belongs to the whole circuit, involving the anode and
>> cathode and all their associated components. There are too many unknowns
>> in that loop to understand what the frequency of the observed dip might
>> be telling us about reverse feed-through from the anode back to the
>> cathode.
>
>Ian,
>Are you saying that a GDO can only dip a "circuit?"

I'm saying you can't even have an L-C resonance without a circuit - 
literally a closed, hard-wired loop.

For example, if you simply connect an L and a C in series, with opposite 
ends floating, you don't have a closed loop so you don't have a resonant 
circuit yet.  Before you can see a resonance and a dip, you must make 
some other connection that closes the loop and completes the circuit.

But the resonance then belongs to the entire circuit you have made - not 
just the obvious inductor and capacitor, but also all the strays that 
you don't know about.

That requirement for a hard-wired circuit only begins to break down if 
components are physically large enough to have significant 
electromagnetic interactions between different parts of themselves - 
antennas being the obvious example, and large anode chokes being 
another.


-- 
73 from Ian GM3SEK