# [Amps] Discrepencies in Pi-net calculators

Han Higasa higasa at plum.ocn.ne.jp
Wed Nov 20 17:08:05 EST 2013

Hi Steve

I am using fomula:

Xc1 = Zi/Q
Xc2 = Zo x  rt(Zi/Zo / (Q^2 + 1 - Zi/Zo))
XL = (QZi + (ZiZo/Xc2))/(Q^2+1)

and with Zi = 50, Zo = 135, f = 28.03 and Q = 2.7
one can obtain

C1 = 306.6 pF
C2 = 194.5 pF
L = 250.9 nH

VK1OD online calculator must be using this scheme.

de Han JE1BMJ

----- Original Message -----
From: "Steve Flood" <kk7uv at bresnan.net>
To: <amps at contesting.com>
Sent: Wednesday, November 20, 2013 11:24 AM
Subject: [Amps] Discrepencies in Pi-net calculators

> I've been working through some Pi-network design for an input tuning
> network
> recently and have tried out several online calculators as well as
> traditional formulas and  common software.  Using the same input variables
> for each tool, I generated three very different results.
>
>
>
> For Rin = 50 ohms, Rout = 135 ohms, f=28.03 MHz, Q=2.7
>
>
>
> Group 1:  Tonne's PI-EL software, ARRL Handbook formulas, and Jim Hawkins
>
> Cin = 93pF, L=457nH, Cout=79pF
>
>
>
> Group 2:  VK1OD online calculator, electronicdesign.com calculator, and
> raltron.com calculator.
>
> Cin = 307pF, L=251nH, Cout=194pF
>
>
>
> Group 3:  EEweb.com calculator, VK2ZAY online calculator, and Impedance
> Matching Network Designer online calculator (sandiego.edu).
>
> Cin=163pF, L=383nH, Cout=113pF
>
>
>
> So then, you can see my dilemma here.   Why are these so different? And
> why
> the common groupings?
>
>
>
> Steve, KK7UV
>
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