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 coprocessor 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 program
automatically avoids calculating it for a 1 ele beam.
- -ZZo
- Zo is the characteristic impedance used when calculating 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).
Both DOS and Unix versions have been built. The DOS version as distributed
requires a 386 PC with a 387 maths coprocessor.
BUGS¶
Bugs should be reported to
david.kirkby@onetel.net. 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 (david.kirkby@onetel.net). with help with converting to
DOS from Dr. Joe Mack NA3T (mack@fcrfv2.ncifcrf.gov)