In a tank circuit, rather than use a Q meter, I prefer to put a suitable
resistor from the plate to ground (and with no HV, of course) feed a signal in
from the output Then use a valve voltmeter to measure the RF volts that appear
at the plate, while an SWR bridge in the feedline shows when the tank is
correctly tuned. This enables you to check for choke resonances, and yet you
don't hit the physical problems of trying to connect a Q meter - which is,
after
all, a pretty unwieldy beast physically to try to connect into an amp. You
can measure working Q by finding the 3dB points, too.
Incidentally, does anyone make Q meters anymore? Over the eyars, I've used Q
meters a lot at work, but I'm not convinced that they're something you can't
do without - like grid dip meters - that's another thing you can get away
without.
73
Peter G3RZP
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