[Amps] Q meter [TSPA]

[Will Matney]

John,

In my opinion, I dont think any instrument can measure the true unloaded 
Q exactly due to too many factors or variables such as stray capacitance 
and inductance. They might show something in the ball park but I don't 
see how it could be possible to show it exact. Especially networks in a 
production enviroment, each will have small differences from one to the 
other, so no one will be the same as the other. As you mentioned about 
the quality of components, no one will be the very exact same as the 
other. Even if measuring a network out of the chassis for an unloaded Q, 
it will change as soon as it's mounted inside the enclosure. There's 
just too many variables, of course that's just my opinion on the subject.

Will

Quote;
The Q meters that use resonance of a component against a known
standard capacitor or inductor are not so useful to measure unloaded
Q of a tank circuit. I am referring to the old Hp and Boonton Q
meters. They are used to measure Q of coils, DF of capacitors, and so
forth. Loaded Q of a tank circuit, i.e., with the tube plate
resistance at one end and the load Z at the other, can be calculated.
Unloaded depends on the quality of components, skin resistance,
connection integrity, etc. In VHF/UHF cavities, the unloaded can be
quite high.

73
John
K5PRO