[Amps] grid resonance

[Peter Chadwick]

Colin said:
>My Millen manual mentions that a grid dip meter can be used to determine Q. 
As I recall, that is done by determining the width of the dip and 
calculating what frequency points are at some reference level. <

If you know what dip corresponds to the 3dB points, I can see that. But that's what you need to know. If you put a VTVM with a good Hi Z RF probe across teh circuit, it becomes easy, and you can then measure impedance by adding the impedance to be measured in shunt if it's high, or series if it's low, and re-measure Q and frequency. Depending on the impedance, you may need to play with the LC ratio. But it's not really using the GDO as anything other than a signal source.

>The old Heath was exceptional<
The only Heath I ever came across was the 'Tunnel Dipper', using a tunnel diode. That I found totally useless. I imagine by now all the tunnel diodes have died - they don't have that long a life, because the very high doping tends to diffuse, even at room temperature, over time.
73
Peter G3RZP