Jon asks:
>OK I GIVE UP!!!! WHY DO THE EQUATIONS NOT JIVE??????
Because the example given isn't resonant.
7.6pF at 28 MHz is -j747.9 ohms. In shunt with 4600 ohms, this gives a
series equivalent of -j728.6 in series with 118.5 ohms. 1 microhenry is j
175.9, so the impedance looking back is -j552.7 ohms in series with 118.5
ohms. If you have a series inductance of j728.6 ohms (4.141 microhenry),
then Q = 728.6/118.5, or 6.15. Similarly, from the parallel case of Rp/Xp,
4600/728.6 = 6.15.
I did a bit of playing on the Smith Chart. While adding the inductance in
series between the plate and C increases the value of C1, it does push up
the circuit Q as a whole, as evidenced by the narrower bandwidth when a
frequency sweep is done. That's working back from the SWR looking back into
the network when loaded with the correct laod impedance at the plate.
73
Peter G3RZP
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