## 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  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)