[Amps] grid resonance

[Peter Chadwick]

Steve said:
>In a finite universe I figure there's always going to be some 
capacitance and/or inductance and/or resistance between the 'open' ends 
of a series L and C, so everything is a parallel circuit. The issue is 
whether it's significant.<

All that does is complicate the circuit. The point I'm trying to get across is that the current induced in the coil produces an EMF in series with the coil. Not in parallel with it - if it was, a non resonant coil in a strong RF field would get hot. So the circuit is a series circuit of the EMF generator, the coil and the capacitor. Self capacitance of the coil gives it a modification to its apparent inductance and Q, and it becomes a more complex circuit.
One of those interesting theoretical matters that can occasionally be of importance, like transmitter conjugate matching arguments.
I must admit that I've never had a lot of use for GDO: the few I've used didn't help much and had all sorts of false dips, and I find that a tracking generator is a good way of finding resonances. For measuring L or C, very convenient is the Almost All Digital Electronics meter. Certainly for most ham work, that gets you into the 'near enough' region.
73
Peter G3RZP