NAME
output - Yagi-Uda project antenna display program
SYNOPSIS
output [ - cehps ] [ -EE_max ] [ -HHmax ] [ -rminimum ] [
-Rmaximum ] [ -ZZo ]
filename
DESCRIPTION
The program output is one of a number of executable programs
that forms part of a set of programs, collectively known as
the Yagi-Uda project , which were designed for analysis and
optimisation of Yagi-Uda antennas. output calculates the
gain, FB ratio, input impedance etc etc of an antenna that
was described by the program input or first and has had the
element currents calculated with the program yagi The data
about the forward gain, VSWR, FB ratio, input impedance etc
is written to a file filename.dat Angular data, giving the
variation of gain with theta and phi is put into a file
filename.gai
Sometimes the program fails to find the 3dB bandwidths in
the E and H planes, and bombs out with a 'zbrent' error.
This can occur if:
(1) The antenna has an almost isotropic pattern, in which
case its never 3dB down, so the 3dB point is undefined.
(2) The 3dB point is outside the assumed angular range. You
then have to either:
(a) Calculate with the -e option, which avoids calculation
of the 3dB E-plane beamwidth or
(b) Do (a) above, then find approximately where the 3dB
point is (from the .gai file -see later), then set options
-E and -H so the program calculates them properly.
The DOS .EXE files as distributed require a 387 maths copro-
cessor to be present and will not run without it. A 486,
Pentium, and I assume later processors of this series will
run it without any extra hardware. The DOS files are no
longer being maintained, so are out of sync with the latest
source.
OPTIONS
-c Calculate the maximum level of any sidelobe - not just
the rear on as the FB ratio tells us. If the sidelobe
and FB ratio are equal, it means the biggest sidelobe
is the rear one. If the Sidelobe is less than the FB
ratio, then another lobe is more significant. Look in
the '.gai' file (see below) to see where it is. This
option slows the program quite a bit.
-e Suppress calculation of the 3dB E-plane bandwidth. This
is sometimes necessary if the programme is unable to
find the 3 dB beamwidth, to prevent an error occuring.
-h Suppress calculation of the 3dB H-plane bandwidth. This
is sometimes necessary if the programme is unable to
find the 3 dB beamwidth, to prevent an error occuring.
-p Put data into a file filename.freq for reading into
gnuplot, and a commmand file filename.gc for gnuplot to
use. (run 'output -p filename' then 'gnuplot
filename.gc' )
-s Suppress all diagnostic output. By default, the program
print the percentage of the job completed.
-EE_max
When the program computes the E-plane 3dB beamwidth, it
assumes the antenna pattern is 3dB down somewhere in
the range 90 to Emax, where E_max is by default 179
degrees. This can fail if it is never 3dB down in the
range, or if it happened to go 3dB down in two or more
points. You can change E_max, if you need to, but
rarely if every should need to. I've never seen a
failure here, but are guarding against one. If you dont
want the pattern, use the -e option instead, which
skips it. See also '-H' below.
-HH_max
When the program computes the H-plane 3dB beamwidth, it
assumes the antenna pattern is 3dB down somewhere in
the range 0 to Hmax, where H_max is by defualt 60
degrees. This can fail if it is never 3dB down in the
range, or if it happended to go 3dB down in two or more
points. Also, if it goes more than 3dB down, but that
starts to come up again. You can change H_max, if you
need to, as failures do occasionally occur. If you dont
want the pattern use -h option instead, which will skip
it.
An obvious example of an antenna where you cant find
the 3dB bandwidth for the H-plane is the 1ele dipole.
The radiation is symmetrical about its axis, so the
level is the same everywhere in the H plane. The pro-
gram automatically avoids calculating it for a 1 ele
beam.
-ZZo Zo is the characteristic impedance used when calculat-
ing the VSWR. By default it's 50 Ohms, but can be
changed to any real, positive value.
filename
is the name of the file containing the antenna
description. It is expected to be in a format created
by input or first - two other programs in the Yagi-Uda
project. The is also expected to exist a binary file
filename.out created by typing yagi filename
Limitations
I'm not aware of any limitations, apart from that filenames,
including full path, can't exceed 90 characters.
FILES
filename ASCII file with antenna description.
filename.out Binary data file, created by yagi.
filename.dat ASCII file with gain, FB ratio etc.
filename.gai ASCII file with angular dependence of gain.
SEE ALSO
first(1), input(1), yagi(1), optimise(1).
PLATFORMS
Both DOS and Unix versions have been built. The DOS version
as distributed requires a 386 PC with a 387 maths coproces-
sor.
BUGS
Bugs should be reported to drkirkby@kirkbymicrowave.co.uk. Bugs
tend actually to be fixed if they can be isolated, so it is
in your interest to report them in such a way that they can
be easily reproduced. The program gives errors if element
lengths are well away from a half-wave (by a factor of ~3)
due to a breakdown in the equations. If the input file is
edited manually and done incorrectly, there can be
unpredictable results.
AUTHORS
Dr. David Kirkby G8WRB (drkirkby@kirkbymicrowave.co.uk). with help
with converting to DOS from Dr. Joe Mack NA3T
(mack@fcrfv2.ncifcrf.gov)
Man(1) output converted with
man2html