[Amps] calculations

[Ian White, G3SEK]

carl seyersdahl wrote:
>  Here's one for the math guru's out there!!
> given the inductance , input and output capacitances, and knowing at least
>the input impedance, (50 ohms) can the impedance on the output side of a
>pi-network be calculated. I have a set of values that the mfr. used in an
>amp, but would like to know what impedance is being matched!!!
> this has been brought up before about the input impedance of the gla1000
>for building the input ckts. It crossed my mind that it might be possible to
>at least find out what the mfrs. had in mind and that might help me in my
>quest . I will likely end up doing it the hard way, which of course is
>mostly just time consuming, but any little bit of info will still help.!!
> thanks to all who answer!!!

It's done using series<>parallel impedance conversions. The formulae are 
in the ARRL Handbook, but it's all a bit tedious. In 1984 I wrote a 
program called NETCALC to automate these processes, and it's 
downloadable with full instructions from:
www.ifwtech.co.uk/g3sek/netcalc/netcalc.htm

The step-by-step worked example is exactly your pi-network problem.

-- 
73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                           'In Practice' columnist for RadCom (RSGB)
New e-mail: g3sek@ifwtech.co.uk
New website: http://www.ifwtech.co.uk/g3sek