[Amps] Pi Networks

[Roger D Johnson]

A reminder to those who forgot or those who never knew. Many
of the pubs and websites used by hams to calculate the values
of Pi and Pi-L networks are WRONG! This is especially true for
networks with low values of Q as used for GG amps inputs.

Elmer Wingfield, W5FD, wrote about this in the Aug 1983 issue
of QST. N1BUG and I just went through this designing an input
circuit for a 6m amp.

Fortunately, the correct information is available. Jim Tonne's
excellent PI-EL program (free) and this web calculator:

http://www.qsl.net/wa2whv/radiocalcs.shtml

give the correct values. Use one of these to design an input
network and then use one of the many other sites for comparison.

73, Roger