Richard Clark wrote:
That's about as useful as saying you do not obtain the maximum miles
per gallon in your car when the ashtray is half full or when the
carpets are at their optimal brushed out nap.

Nope, it's as useful as saying one cannot get the
advertised miles per gallon when one is driving
the car uphill at 80 mph. Miles per gallon is
related to incline and speed. Frequency, gain,
and F/B ratio are related. I surprised you don't
know that.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com