Actually the BFT is out of production since quite a while there are more stable and higher Ft devices on the market.
73 de N1UL Sent from my iPhone > On Oct 14, 2018, at 12:47 PM, Dana Whitlow <k8yumdoo...@gmail.com> wrote: > > 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 < > time-nuts@lists.febo.com> 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 -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.