[Amps] Pi-L values

[Tom W8JI]

> mounting hardware.  I would not use the Pi-L numbers in 
> the ARRRRRRGGGL
> handbook as they have been wrong for years,IMHO.

Bob,

Are you sure the ARRL handbook is wrong?

There are many reactance combinations that will work in that 
circuit configuration. There are many combinations with the 
tuning and loading caps at about a 2.5 ratio that work.

For example, a double L Q of 4 and an intermediate impedance 
value of about 1400 ohms will produce about that ratio. So 
will a pi tank Q of about 20 with an intermediate impedance 
of 500 ohms.

As a matter of fact you can use a 2.5 ratio and by setting 
the ratio of the two inductors move the tank Q all over the 
place. The higher the Q, the lower the intermediate 
impedance has to be. The lower the Q, the higher the 
intermediate impedance has to be to maintain a 2.5 ratio.

If Sunair sold amplifiers that worked (and I would bet they 
did) they probably optimized the networks for that 
application. They didn't reach around to a place near their 
back pockets and pull a Q and tell the rest of the world 
that would be the only Q that works. If they said the ratio 
was 2.5, I'd bet money that ratio is optimum for their goals 
which would be bandwidth and harmonic suppression 
requirements.

I don't understand why so many people think there is only 
one combination that "works", and why we go through so much 
trouble to obtain a "Q" that at best is just a wild guess of 
an optimum  value. What do we think, only one Q value will 
work?

73 Tom