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
Date: Thu, 06 Jan 2005 15:26:28 -0500
From: Will Matney <craxd1@ezwv.com>
Subject: [Amps] PLATE RESISTENCE
To: amps@contesting.com
....
Even though the Q is a factor plugged into the formula, there are "Q
meters" for testing the actual Q of a built component-network. After the
tank is complete, or just the tank coil itself, the actual Q can be
found with the meter and then compared to the value you arrived at from
the formulas. Most LCR meters have the capacity to test the Q of a
component or circuit. There are more accurate Q meters available though.
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