The page below is reprinted from
Harry Whitfield's website and is included here on SSS Online with his kind permission. If you have
any questions about the operation of this program, please contact Harry at
The concepts and command names follow those in NETCALC, but the coding
and design of this program are entirely new.
This program can also display impedances on a diagram similar to the
well-known Smith Chart.
The L-section code is based on a PERL program
by Claude Frantz ().
NETCALC is available from the above link and can be executed on an IBM
PC under various versions of the Microsoft Windows Operating System.
Indeed, I have also used it under SoftWindows on an Apple iMac.
However, I wanted a version that would run native on a Macintosh as
well as on a PC and thought that writing and testing such a program
would teach me a lot about network analysis and Smith Charts.
Here is a view of the program when it first opens.
Data is entered via the panel at the top right and transfered to the X register
by use of the + and || buttons.
Operations on the X (and Y) register(s) are performed using the
buttons at the bottom right. The command names are the same as those
in NETCALC, so you should read the NETCALC instructions before
attempting to use the program.
The X and Y registers appear in the panel at the top left. The X register is
also shown in parallel form in the P register.
The environment parameters are entered in the middle left panel, apart from Z0
which must first be entered via the data panel and transferred from X to Z0 using the
Z0 button. Complex characteristic impedances can be entered if desired.
Many of the circuit parameters are recomputed at every operation. Others are computed
The panel at the bottom left displays the normalised value of X in the N register
and the reflection coefficient (in polar form) in the rho register. The VSWR is
displayed in the Z register, which is also used as a general display register.
There are buttons to compute the modulus of X and of N, and four buttons to produce
a rudimentary display similar to that on a Smith Chart.
Buttons and Operations
Data input (top right)
R + L X -> Y, R + L -> X
R || L X -> Y, R || L -> X
R + x X -> Y, R + x -> X
R || x X -> Y, R || x -> X
R + C X -> Y, R + C -> X
R || C X -> Y, R || C -> X
Calculation (bottom right)
Rn X -> Y, Rn -> X
E X <=> Y
+ X + Y -> X, 0 -> Y
|| X || Y -> X, 0 -> Y
?n Rn -> Z
J X* -> X
* X * Factor -> X
/ X / Factor -> X
Mn X -> Mn
Z0 X -> Z0
T X + T(Z0, F, V, length) -> X
C Y -> X, 0 -> Y
Q x/r -> Z, where X = r + jx
X if x >= 0, L = x/(2¼F) -> Z, where X = r + jx
if x < 0, C = (-2¼F)*x -> Z, where X = r + jx
L L(X, Z0, F, V) -> Z
W (1 +|rho|)/(1 - |rho|) -> Z,
where rho = ((X/Z0) - 1)/((X/Z0) + 1)
LS Displays L-sections matching the load X to the real part of Z0
Calculation (bottom left)
|X| |X| -> Z
|N| |X/Z0| -> Z
Chart Drawing (bottom left)
The C, R, S and CS buttons are used as follows:
C draws the VSWR circle on the chart.
R places the current N (ie rho) value on the chart.
S displays the chart.
CS clears the chart.
Here is a view of a chart:
NetCalc is Copyright (C) 2001-2003 Harry Whitfield (G6AUC), All Rights Reserved.
Permission is hereby granted, free of charge, to any person who obtains a copy of
this software and associated documentation files (the "Software"), to use the
Software for personal or educational purposes, subject to the following
The above copyright notice, and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS," WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL HARRY WHITFIELD
OR THE UNIVERSITY OF NEWCASTLE UPON TYNE BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN