[HomeBrew] Pixie II Output Filter

[Eugene Crist]

I'm building a Pixie II from scratch for 40m and I want to build a second
one for 20m. Besides the crystal I'll have to replace L3, the inductor in
the output filter. According to the instructions, it says to use the formula
f=1/(2*PI*(SQRT(LC))), but when I use this formula I come up with different
resonant frequencies than what the transceivers are supposed to operate. For
example, if I want to build an 80m Pixie it says to use a 2.2 uH inductor.
The parallel caps are both 820 pF, so adding the caps results in 1640 pF, so
when I insert 1 uH (L) and 1640 pF (C) into the formula I come up with a
resonant frequency of 2.651 MHZ instead of something in the 80m band. The
same goes for the 40m Pixie, if I use the suggested 1 uH inductor with the
two 820 caps I come up with a resonant frequency of 3.932 MHZ. Obviously I'm
not calculating something correctly so if anyone can point me in the right
direction I'd certainly appreciate it.

Thanks, Gene (KB3ONA)