Airy,
What you said would be relevant only if you were trying to determine circuit
losses due to "unloaded" Q of the components. I believe Paul is trying to
determine the 'loaded" Q in order to obtain best selectivity (narrowest
bandwidth). Is this true Paul?

In order to obtain maximum selectivity, the loaded Q needs to be as high as
possible. In the case of a resonant 'tank', the tank reactances are loaded
by the external environment. The circuit Q (or 'loaded' Q) in this case is
Q=R/X. In order to maximize loaded Q, the X term (reactance) needs to be
minimized. This means low L and high C.

In any case, the actual circuit losses will be a function of the ratio of
unloaded Q (Q of the components) to loaded Q. The higher the unloaded Q of
the components, the lower the losses in the circuit.

Joe
W3JDR


"Airy R. Bean" wrote in message
...
Reduce the L to reduce the resistive loss - the essence of L
is the energy stored in its current carrying, and it is the current that
causes I^2 R losses. The energy stored in the C is static. (Yes, there
are some losses in polarising the dielectrics but these are small enough
to be ignored)

"Paul Burridge" wrote in message
...
ISTR that one can improve Q in resonant tanks by having a low L-C
ratio. Or was it high L-C ratio. I can't remember but need to know.