Corby, Now that I learn that the BFT66 is a "wild one", I'd remark that stability is indeed the likely issue. I was puzzled by the presence of that capacitor in the first place, as this circuit is clearly neither tuned nor of especially high frequency capability.
Could you tell us more: what kind of maser is this, and what is the role of this amplifier in this maser? And if it's a hydrogen maser, why you lucky dog! Dana On Sun, Oct 14, 2018 at 11:41 AM Ulf Kylenfall via time-nuts < [email protected]> wrote: > > The BFT66 if that is the type ( a bit difficult to read ) is a really > "wild one" on VHF. I have used it and unless surrounded by proper > decoupling networks in a well designed circuit it can and will oscillate. > I would have used a spectrum analyzer to check for any > unwantedoscillations well above this circuits operating frequency. > And also checked with a scalar network analyzer for possibleinstabilities > in the circuits gav vs frequency. > Also the generation of unwanted overtones can be one causeof adding the > capacitor where it is. > One other peculiarity with the BFT66 is that it does not use themore or > less standardized E-B-C pin configuration. > One design that I came across that used the BFT66 was very difficultto > make stable. After some time I gave up on it and replacedthe BFT66 with > BFY90. > Best Reagards > Ulf KylenfallSM6GXV > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
