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OPTIMISE(1)		    General Commands Manual		   OPTIMISE(1)

NAME
       optimise	- Yagi-Uda project antenna optimiser

SYNOPSIS
       optimise	 [  -dhvwO  ]  [  -aangular_stepsize  ]	[ -bboom_extension ] [
       -ccleanliness_of_pattern	] [ -eelements ] [ -fFBratio ] [  -gGA_optimi-
       sation_method  ]	 -lpercent  ] [	-mmin_offset_from_peak ] [ -ooptimisa-
       tion_criteria ]	[  -ppopulation	 ]  [  -rresistance  ]	[  -sswr  ]  [
       -tlength_tolerance ] [ -xreactance ] [ -AAuto_gain ] [ -CCurrents_simi-
       lar ] [	-Fweight_FB  ]	[  -Gweight_gain  ]  [	-Kkeep_for_tries  ]  [
       -Pweight_pattern_cleanliness ] [	-Rweight_resistance ] [	-Sweight_swr ]
       [ -Tposition_tolerance ]	[ -WWeighted_algorithm ] [  -Xweight_reactance
       [ -ZZo ]	filename iterations

DESCRIPTION
       The  program  optimise  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.  optimise attempts to optimise	the performance	of a Yagi  an-
       tenna for one or	more parameters	that are considered important, such as
       gain, F/B ratio,	VSWR etc.  It  does  this  by  randomly	 changing  the
       lengths and positions, of one or	more elements, then comparing the per-
       formance	before and after the change.  Any improvements are written  to
       a  new  file  called filename.bes where filename	is the name of the an-
       tenna description file created by input or first

       When Yagi's are designed	on paper, or using this	program, its  possible
       that  they will be almost impossible to build, if their performance de-
       pends too critically on the dimensions. To determine  if	 this  is  the
       case  with a design, we run optimise with just the options 't' and 'T'.
       These specify the tolerance with	which you can build the	 antenna,  ex-
       pressed	as a standard deviation	in mm. In this case, instead of	trying
       to optimise a poor design, optimise will	calculate  the	minimum	 gain,
       maximum VSWR, and minimum FB ratio of a number of designs, all slightly
       different from the input	file. 99.7% of the components lie within 3  SD
       of the mean, so if you think you	can cut	elements to with 1 mm 99.7% of
       the time, specify t0.33.	If you can put them in the boom	to within 3 mm
       99.7% of	the time, specify T1.

       If  while optimise is running using the methods that require weights to
       be attached to the gain,	FB, SWR	etc, it	becomes	apparent, the  weights
       are  not	 optimum,  its possible	to pause the program and re-adjust the
       weights.	If a file with the name	of changes  is	created,  the  program
       will pause, then	request	new weights are	entered	at the keyboard.

AVAILABILITY
OPTIONS
       -d     Print  the default values	of all the configureable parameters to
	      stdout. Typing this option with any option that changes a	param-
	      eter  (see  below)  will display the new value of	the parameter,
	      rather than the default.

       -h     Print a help message.

       -v     Print verbose status information.

       -w     Instead of optimising at one fixed frequency  (the  design  fre-
	      quency), this directs the	program	to optimise at 3 separate fre-
	      quencies (lowest,	design and highest) then to  average  data  at
	      all 3. This option is better for wideband	antenna. Note that the
	      input impedance printed is at the	design frequency, *not*	 aver-
	      aged  over  3  frequencies. Averaging an impedance, is likely to
	      give a very misleading impression. The impedance averaged	over 3
	      frequencies  can	be  50+i0  Ohms, even if the VSWR is very poor
	      over all 3 frequencies, as the following 3 pieces	of data	show.
	      Z=147 + j	300  SWR= 15.46:1
	      Z=2   + j	100  SWR= 125:1
	      Z=1   - j	400  SWR= 3250:1
	      note in the above	three cases, the average impedance is 50  +  j
	      0, but average SWR is 1130:1.

       -O     Over-optimisation	 allowed.   By	default,  the program does not
	      over-optimise a parameter. For example, an SWR of	1.01  is  usu-
	      ally  considered	good enough and	any change, as long as the SWR
	      stayed good, typically below 1.1:1, would	be  allowed,  even  if
	      the  SWR	rose. By default, FB's of 27 dB, VSWR's	of 1.1 are ac-
	      ceptable.	However, by using the -O option, you  can  insist  the
	      program always improves things, no matter	how good they are.

       -aAngular_stepsize
	      When  optimimising  by  trying to	get a clean pattern, specifies
	      the step size to use when	looking	for features in	 the  pattern.
	      If  its  set  too	 small,	the program  runs slow.	If its set too
	      large, the program may miss features in the pattern, such	 as  a
	      sidelobe.	 Then  the  resulting  antenna will have poor sidelobe
	      performance, even	though you think it will be good. The  program
	      attempts	to calculate a sensible	value, based on	1/10th the ap-
	      proximate	3 dB beamwidth,	if you don't set.

       -bboom_extension
	      Generally	speaking, the gain  of	a  Yagi	 increases  with  boom
	      length.  Hence  the optimiser would often	give you a Yagi	with a
	      much longer boom than the	input file. This may not be  what  you
	      desire due to space restrictions.	These long antennas often have
	      high gain, but are very narrow in	bandwidth. The default	limits
	      the  antenna to 10x the original length, which means effectively
	      there is no boom length limitation.  You can adjust the percent-
	      age  by  setting boom_extension to whatever you wish.  -b30 will
	      limit the	boom to	no  more  than	30%  more  than	 the  original
	      length.

       -ccleanliness_of_pattern
	      Specify the number of dB down on the peak	gain to	aim to get the
	      pattern. Any antenna pattern cleaner than	this will  not	effect
	      the fitness, nor will it be considered any better	when comparing
	      to antenna designs. 20 dB	seems reasonable, so  the  default  is
	      20,  but	this  may of course change if it's deceided too. Check
	      the source  code	to  be	certain	 (see  REASONABLE_SIDELOBE  in
	      yagi.h).

       -eelements
	      is  an  integer  which  specifies	 the type of elements that are
	      changed in the optimisation cycle.  Possible values are:
	       1 - alter only the driven element(s) length (useful to bring to
	       resonance)
	       2  -  alter  only the driven element position. Don't change its
	       length.
	       4 - alter only the reflector length. The	position is always  at
	       x=0.
	       8 - alter only the director lengths. Don't change positions.
	       16 - alter only the director positions. Don't change lengths.
	       32  -  randomly adjust one element length, then makes all other
	       the same. Don't change the positions.
	       64 - apply a linear taper to the	lengths.
	       128 - Set the driven element to a resonate length. It  may/may-
	       not be altered after the	first run, depending on	the whether or
	       not '1' is invoked too. Eg -e128	will make it resonate and keep
	       it there	forever. However '-e129' will bring to resonance, then
	       alter to	maximuse performance.
	      The elements altered is made from	a logical AND of the above, so
	      for  example  to	alter  everything,  except  the	driven element
	      length, use -e30,	since 2+4+8+16=30.  The	 default is equivalent
	      to  -e31 , which changes everything possible. Note the reflector
	      position is *never* changed. It's	always at x=0.

       -fFBratio
	      When optimising an antenna, consider any FB ratio	 greater  than
	      FBratio  dB to be	equal to FBratio dB. This avoids optimising to
	      a	very high FB ratio, which is impracticable, as	the  bandwidth
	      over  which  this	 FB ratio will be maintained is	very small and
	      mechanical considerations	will prevent you from constructing  it
	      with such	a high FB ratio	anyway.	If this	was not	prevented, you
	      might just happen	to get an antenna with 100 dB  FB  ratio,  but
	      poor gain	and swr. Since by default all parameters must improve,
	      the optimisation routine will most likely	never  being  able  to
	      improve  on  the 100 dB FB ratio,	so no improvement will result.
	      Most people would	prefer to get a	few extra dB of	gain, even  if
	      the FB ratio dropped to 30 dB.

       -gGA_optimisation_method
	      Use a genetic algorithm. With the	genetic	algorithm, the program
	      does not take any	account	any of the  initial  lengths/positions
	      of elements specified in the input file. Rather it works by ini-
	      tialising	a number of different antenna, then computing a	 'fit-
	      ness' value for each.  The fitness value can depend on the gain,
	      FB, real part of the input impedance, reactive part of the input
	      impedance, VSWR or the level of the sidelobes. The integer after
	      the g tells the optimiser	what to	consider.  -g1	Use gain
	      -g2  Use FB
	      -g4  Use R
	      -g8  Use X
	      -g16 Use the SWR
	      -g32 Use the level of the	sidelobes.

	      You can use a logical AND	of these, so for example -g49 will use
	      a	 genetic  algorithm,  optimising  for  gain,  swr and sidelobe
	      level, since 1(gain)+16(SWR)+32(sidelobe level)=49.

       -lpercent
	      is a parameter (floating point number) which specifies the maxi-
	      mum percentage change in the positions or	lengths	of an elements
	      at each iteration. If the	option is not used, it will be set in-
	      ternally	at 10% for the first 25% of the	iterations, 1% for the
	      next 25%,	0.1% for the third 25% of the iterations and 0.01% for
	      the  last	 25%  of the iterations. If set	to a positive number x
	      (eg optimise -l 0.3 145e10) then the percentage will be  set  at
	      x%  for 25% of iterations, x/10 for the  next 25%, x/100 for the
	      next 25 and x/1000 for the last 25%. If set to a negative	number
	      y	 (eg  optimise	-l  -0.5  145e10) then the paramters will stay
	      fixed at y% (in this example 0.5%) all the time.

       -mmin_offset-from_peak
	      Sets the minimum angle in	degrees	offset from theta=90  degrees,
	      where  the  side	lobes  start  and  the main lobe finishes. The
	      higher the gain, the smaller it should be. It is set  internally
	      if not set on the	command	line.

       -ooptimisation_criteria
	       1 -  Assume better if the gain has increased.
	       2 -  Assume better if the front to back ratio has improved.
	       4  -   Assume better if the real	part of	the input impedance is
	       closer to the value that	the program was	compiled for,  or  set
	       using  the  '-Z'	option.	 This will usually be 50 Ohms, but you
	       may wish	to set this to 12.5 Ohms if you	use a 4:1 balun.  Gen-
	       erally you can get higher gain from a Yagi if you allow the in-
	       put impedance to	fall, but of course feeding  it	 becomes  more
	       difficult.
	       8  -   Assume better if the magnitude of	the reactive component
	       of the input impedance is lower (ie. the	antenna	is nearer res-
	       onance).
	       16 - Assume better if the VSWR is lower.
	       32 - Assume better if the level of all sidelobes	is lower.
	      The  optimisation_criteria  may  be formed from a	logical	AND of
	      these numbers, so	for example choosing -o19 will only consider a
	      revised  antenna	better than the	previous, if the SWR, gain and
	      F/B ratio	have all simultaneously	improved.

	      Clearly an antenna which originally had 12 dB  gain  and	1.01:1
	      VSWR but then changes to 20 dB gain @ 1.02:1 VSWR, would to most
	      people be	better,	even though the	VSWR  has  increased.  By  de-
	      fault,  optimise	only optimises to sensible maximums, so	to not
	      let the optimisation stall prematurely. By running optimise with
	      no arguments, the	program	will list the limits of	acceptability.
	      These might be typically F/B ratio > 27 dB, VSWR < 1.1:1,	magni-
	      tude  of	input  reactance less than 5 Ohms and the real part of
	      the  input  impedance  within  5	Ohms  of  Zo.  Choosing	  -o19
	      (1+2+16=19)  will	optimise for gain (since G=1), FB (since FB=2)
	      and SWR (Since SWR=16), but would	consider a higher gain and  FB
	      ratio  antenna better than a previous one, even if the SWR rose,
	      as long as it stayed below 1.1:1 (or as was set during  compila-
	      tion).  The default behaviour (no	options) is equivalent to -o37
	      which optimiseas for gain(1), the	real part of the input	imped-
	      ance(4)  and  sidelobes(32) but this may be changed at any time,
	      so type optimise -d to check the current settings. If you	insist
	      on  the program optimisang for the very best of all selected pa-
	      rameters,	use the	-O option too, but be warned the  optimisation
	      will probely stick once it gets one parameter really good.

       -ppopulation
	      This  determines	the  initial population	used  with the genetic
	      algorithm.

       -rresistance
	      When optimising an antenna, consider any input resistance	closer
	      to  Zo  (usually 50 Ohms)	than resistance	Ohms to	be acceptable.
	      This avoids optimising to	an input resistance too	close  to  Zo,
	      which  is	 impracticable,	 as the	bandwidth over which the input
	      resistance could be maintained is	very small and mechanical con-
	      siderations  will	prevent	you from constructing the antenna with
	      such an ideal input resistance. If this was not  prevented,  you
	      might  just happen to get	an antenna with	an input resistance of
	      50.000001	Ohms, but poor gain, FB	and possibly even a poor  swr,
	      if the antenna is	well away from resonance. Since	by default all
	      parameters must improve, the optimisation	routine	will get  most
	      likely  never  being  able to improve on the antenna, whereas we
	      might be happier with a few more dB gain,	if  the	 input	resis-
	      tance went to 50.1 Ohms. It should be noted that the default op-
	      timisation routine never	uses  the  input  resistance  directly
	      (only VSWR), so this option cant be used without the '-o'	option
	      to optimise for other than the default  parameters  (gain,  VSWR
	      and FB ratio).

       -sswr  When optimising an antenna, consider any SWR less	than swr to be
	      equal to swr This	avoids optimising to a very low	swr, which  is
	      impracticable,  as the bandwidth over which such a low swr could
	      be maintained would be very small	and mechanical	considerations
	      will  prevent  you  from constructing such an antenna anyway. If
	      this is was not prevented, you might just	happen to get  an  an-
	      tenna  with an swr of 1.000000000001:1, but poor gain, FB	ratio.
	      Since by default all parameters must improve,  the  optimisation
	      routine  will most likely	never being able to improve on the an-
	      tenna, even though in practice you would like to get a few extra
	      dB  of  gain  if	the  SWR would rise to 1.02:1. The default was
	      equivalent to -s1.1 but run optimise -d to display this and  any
	      other defaults.

       -tlength_tolerance
	      length_tolerance is the standard deviation in mm of the accuracy
	      with which you can cut elements. Since 99.7% of elements will be
	      with 3 standard deviations of the	mean length (stats theory says
	      this), set -t0.2 if virtually all	(well 99.7%) of	 elements  are
	      within 3x0.2=0.6 mm of the correct length. This option *must* be
	      used with	the '-T'  option and can't be used with	any other  op-
	      tions apart from

       -xreactance
	      When optimising an antenna, consider any input reactance of less
	      than reactance to	be reactance.  This avoids over	optimising the
	      reactance, at the	expense	of something else.

       -Aauto_gain
	      When  the	auto_gain option is used. the program maximes the gain
	      of the antenna (ignoring all other parameters such  as  SWR,  FB
	      ratio etc) by adjusting the length (not position)	of one element
	      only. -A-1 will maximuse the gain, by adjusting  the  length  of
	      the  reflector,  -A0  will  maximise  the	 gain by adjusting the
	      length of	the driven element. Its	generally *not*	a good idea to
	      maximise	the gain by adjusting the driven element, but the pro-
	      gram lets	you do it, but using the option	-A0.  Using  -A1  will
	      maximise gain by adjusting the length of the first director, -A2
	      the second director and so on, up	to the last director. You must
	      check  carefully that the	input impedance	in particular does not
	      fall to silly values if you use this option. On a	yagi with many
	      elements (> 10 or	so), you can pretty safely maximise the	8th or
	      more director, but doing it on the reflector, driven element  or
	      early  directors	often leads to silly input impedances -	so be-
	      ware!  Note, no matter how many  iterations  you	specify,  this
	      process is only done once.Its unlikely you will be able to do it
	      again, without things going out of hand, but if you must do  it,
	      you must re-run 'optimise' again.

       -Ccurrents_similar
	      If  this	option	is used, where currents_similar	is an integer,
	      the program looks	to make	the currents in	the last currents_sim-
	      ilar elements as similar as possible. It computes	the sum	of the
	      squares of the deviations	of the absolute	values of the  element
	      currents	from  the mean.	If this	falls, and the criteria	speci-
	      fied with	the -W option is also satisfied, the antenna  is  con-
	      sidered  better. If currents_similar is three less than the num-
	      ber of directors,	it tries to make the currents in the  the  di-
	      rectors  (but  ignoringing  the  first  3)  all similar. If cur-
	      rents_similar is equal to	the number of directors, it  tries  to
	      make  all	the directors have similar currents. If	currents_simi-
	      lar is one more than the number of directors, it tries  to  make
	      all  the	directors  and the reflector have similar currents. If
	      currents_similar is equal	to the total number of elements,  then
	      it fails with an error message.

       -Fweight_FB
	      is the floating point number (default 1.0) specifying the	weight
	      to attach	to the FB ratio	of the antenna when using the '-W' op-
	      tion, which calculates a fitness for the antenna based on	one or
	      more parameters (FB, gain, input	resistance,  input  reactance,
	      SWR, cleanliness of antenna pattern). The	'-F' option is similar
	      to the options -G, -P, -R, -S, -X	 (which	 specify  weights  for
	      gain, pattern cleanliness, input resistance, SWR and input reac-
	      tance).  When using the -W option	the exact  algorithm  used  to
	      compute  the fitness (and	hence the effect of this parameter) is
	      best checked by looking at the source code (see perform.c). This
	      is one area of constant program improvement/changes/development,
	      so its difficult to say exactly the effect  the  parameter  has.
	      However, increasing the weight of	a parameter (using the -F, -G,
	      -R, -S or	-X options) will make  the associated parameter	have a
	      greater effect on	the fitness.  However, unless you optimise for
	      a	high FB	ratio with the -W option, then setting the  -F	option
	      will  have no effect. For	example, setting the options -F2.5 -W1
	      is a complete waste of time. There you have used the -W1	option
	      to  optimise  only  for gain (see	-W option section of man page)
	      but have changed the weight of the FB ratio from its default 1.0
	      to  2.5.	If you are not optimising for FB ratio,	the weight you
	      attach to	it is irrelavent.

       -Gweight_gain
	      is the floating point number (default 1.0) specifying the	weight
	      to attach	to the gain of the antenna when	using the '-W' option,
	      which calculates a fitness for the antenna based on one or  more
	      parameters  (FB,	gain,  input resistance, input reactance, SWR,
	      cleanliness of antenna pattern). The '-G'	option is  similar  to
	      the options -F, -P, -R, -S, -X (which specify weights for	FB ra-
	      tio, pattern cleanliness,	input resistance, SWR and input	 reac-
	      tance).	When  using  the -W option the exact algorithm used to
	      compute the fitness (and hence the effect	of this	parameter)  is
	      best checked by looking at the source code (see perform.c). This
	      is one area of constant program improvement/changes/development,
	      so  its  difficult  to say exactly the effect the	parameter has.
	      However, increasing the weight of	a parameter (using the -F, -G,
	      -R, -S or	-X options) will make  the associated parameter	have a
	      greater effect on	the fitness.  However, unless you optimise for
	      gain with	the -W option, then setting the	-G option will have no
	      effect. For example, setting the options -G2.5 -W2 is a complete
	      waste  of	 time.	There you have used the	-W2 option to optimise
	      only for FB ratio	(see -W	option section of man page)  but  have
	      changed  the  weight of the gain from its	default	1.0 to 2.5. If
	      you are not optimising for gain, the weight you attach to	it  is
	      irrelavent.

       -Kkeep_for_tries
	      keep_for_tries  is  the number of	tries for the optimise to per-
	      sist using the original data file	as the starting	point for  op-
	      timisation.  By default it is 1, which means the program immedi-
	      ately looks from a new position once a better one	is  found.  It
	      is  theeoretically  possible  that this might result in a	quick,
	      but poor local maximum. If however, keep_for_tries is  1000,  it
	      will  stay  at  a	position for 1000 iterations after finding the
	      last best	result,	before considering this	to be a	 global	 opti-
	      mum.  Then  it  starts for the new position. In practice,	I have
	      found this option	to make	matters	worst in most  cases.  It  was
	      added to avoid the local-minimum problem,	but it appears the op-
	      timisation surface is pretty smooth, so it just slows  the  pro-
	      gram,  without  gaining  much. Anyway, it	can stay as an option,
	      but check	the results with/without carefully before using	exten-
	      sively.

       -Ppattern_cleanlyiness
	      is the floating point number (default 1.0) specifying the	weight
	      to attach	to the cleanness of the	antenna	pattern	when using the
	      '-W' option, which calculates a fitness for the antenna based on
	      one or more parameters (FB, gain,	input resistance, input	 reac-
	      tance,  SWR, cleanliness of antenna pattern). The	'-P' option is
	      similar to the options -F, -G, -R, -S, -X	(which specify weights
	      for  FB ratio, gain, input resistance, SWR and input reactance).
	      When using the -W	option the exact algorithm used	to compute the
	      fitness (and hence the effect of this parameter) is best checked
	      by looking at the	source code (see perform.c). This is one  area
	      of constant program improvement/changes/development, so its dif-
	      ficult to	say exactly the	effect the parameter has. However, in-
	      creasing	the weight of a	parameter (using the -F, -G, -R, -S or
	      -X options) will make  the associated parameter have  a  greater
	      effect on	the fitness.  However, unless you optimise for a clean
	      antenna pattern with the -W option, then setting the  -P	option
	      will  have no effect. For	example, setting the options -P2.5 -W1
	      is a complete waste of time. There you have used the -W1	option
	      to  optimise  only  for gain (see	-W option section of man page)
	      but have changed the weight of the pattern cleanliness from  its
	      default 1.0 to 2.5. If you are not optimising for	a clean	radia-
	      tion pattern, the	weight you attach to it	is  irrelavent.	  With
	      appropiate  use  of  the	-W option (eg -W49 for gain, SWR and a
	      clean pattern), the computer program finds the level of the most
	      significant  sidelobe, wherever it may be	outside	the main bean.
	      It then optimises	to reduce this.	The -P	option	tells  it  how
	      much weight to put on reducing this sidelobe.

       -Rweight_resistance
	      is the floating point number (default 1.0) specifying the	weight
	      to attach	to the obtaining an input resistance close  to	Zo  on
	      the  antenna when	using the '-W' option, which calculates	a fit-
	      ness for the antenna based on one	or more	parameters (FB,	 gain,
	      input  resistance,  input	reactance, SWR,	cleanliness of antenna
	      pattern).	The '-R' option	is similar to the options -F, -G,  -P,
	      -S, -X (which specify weights for	FB, gain, pattern cleanliness,
	      SWR and input reactance).	 When using the	-W  option  the	 exact
	      algorithm	 used  to compute the fitness (and hence the effect of
	      this parameter) is best checked by looking at  the  source  code
	      (see  perform.c).	 This is one area of constant program improve-
	      ment/changes/development,	so its difficult to  say  exactly  the
	      effect  the  parameter  has. However, increasing the weight of a
	      parameter	(using the -F, -G, -R, -S or  -X  options)  will  make
	      the  associated  parameter have a	greater	effect on the fitness.
	      However, unless you optimise for an an input resistance close to
	      Zo,  with	the -W option, then setting the	-R option will have no
	      effect. For example, setting the options -R2.5 -W1 is a complete
	      waste  of	 time.	There you have used the	-W1 option to optimise
	      only for gain (see -W option  section  of	 man  page)  but  have
	      changed  the  weight  of	the resistance from its	default	1.0 to
	      2.5. If you are not optimising for an input resistance close  to
	      Zo, the weight you attach	to it is irrelavent.

       -Sweight_swr
	      is the floating point number (default 1.0) specifying the	weight
	      to attach	to the SWR of the antenna when using the '-W'  option,
	      which  calculates	a fitness for the antenna based	on one or more
	      parameters (FB, gain, input resistance,  input  reactance,  SWR,
	      cleanliness  of  antenna pattern). The '-S' option is similar to
	      the options -F, -G, -P, -R, -X (which specify  weights  for  FB,
	      gain,  pattern  cleanliness,  input  resistance  and input reac-
	      tance).  When using the -W option	the exact  algorithm  used  to
	      compute  the fitness (and	hence the effect of this parameter) is
	      best checked by looking at the source code (see perform.c). This
	      is one area of constant program improvement/changes/development,
	      so its difficult to say exactly the effect  the  parameter  has.
	      However, increasing the weight of	a parameter (using the -F, -G,
	      -R, -S or	-X options) will make  the associated parameter	have a
	      greater effect on	the fitness.  However, unless you optimise for
	      SWR with the -W option, then setting the -S option will have  no
	      effect. For example, setting the options -S2.5 -W1 is a complete
	      waste of time. There you have used the -W1  option  to  optimise
	      only  for	 gain  (see  -W	 option	 section of man	page) but have
	      changed the weight of the	SWR from its default 1.0  to  2.5.  If
	      you  are	not optimising for SWR,	the weight you attach to it is
	      irrelavent.

       -Tposition_tolerance
	      position_tolerance is the	standard deviation in mm of the	 accu-
	      racy  with  which	 you can cut elements. Since 99.7% of elements
	      will be with 3  standard	deviations  of	the  correct  position
	      (stats  theory says this), set -T2 if virtually all (well	99.7%)
	      of elements are within 3x2=6 mm of the correct position.This op-
	      tion *must* be used with the '-t'	 option	and can't be used with
	      any other	options	apart from

       -WWeighted_algorithm
	      Try to get an antenna which is better according  to  a  weighted
	      combination  of  parameters, rather than require them all	to im-
	      prove. The integer specifies what	to consider  in	 the  weighted
	      parameters.
	      W1 Gain.
	      W2 FB
	      W4 R
	      W8 X
	      W16 SWR
	      W32 SIDE_LOBE
	      You  can	logically  AND these together, so for example -W3 will
	      optimise using a weighted	combination of gain and	FB. -W49, will
	      use a weighted combination of gain, swr and sidelobe leve, since
	      32+16+1=49.

       -Xweight_reactance
	      is the floating point number (default 1.0) specifying the	weight
	      to attach	to achieving a low input reactance on the antenna when
	      using the	'-W' option, which calculates a	fitness	 for  the  an-
	      tenna  based  on	one or more parameters (FB, gain, input	resis-
	      tance, input reactance, SWR, cleanliness	of  antenna  pattern).
	      The  '-X'	 option	is similar to the options -F, G, -P, -R	and -S
	      (which specify weights for FB ratio, gain, pattern  cleanliness,
	      input  resistance, and SWR).  When using the -W option the exact
	      algorithm	used to	compute	the fitness (and hence the  effect  of
	      this  parameter)	is  best checked by looking at the source code
	      (see perform.c). This is one area	of constant  program  improve-
	      ment/changes/development,	 so  its  difficult to say exactly the
	      effect the parameter has.	However, increasing the	 weight	 of  a
	      parameter	 (using	 the  -F,  -G, -R, -S or -X options) will make
	      the associated parameter have a greater effect on	 the  fitness.
	      However,	unless you optimise for	a low input reactance with the
	      -W option, then setting the -X option will have no  effect.  For
	      example,	setting	 the  options -X2.5 -W1	is a complete waste of
	      time. There you have used	the -W1	option to  optimise  only  for
	      gain  (see  -W  option section of	man page) but have changed the
	      weight of	the reactiance from its	default	1.0 to 2.5. If you are
	      not  optimising for a low	input reactance, the weight you	attach
	      to it is irrelavent.

       -ZZo
	      Zo is the	characteristic	impedance  used	 when  evaluating  the
	      VSWR, reflection coefficient and other similar calculations. The
	      optimiser	usually	tries to bring the input impedance of the  an-
	      tenna to this value. It is set by	default	to 50 Ohms, so the de-
	      fault is equivalent to -Z50 but may be set to any	positive  num-
	      ber.  Set	to 12.5	Ohms if	you are	going to feed the antenna with
	      a	4:1 balun. Generally speaking, the  gain  of  a	 Yagi  can  be
	      higher for low input impedances, but of course such antennas are
	      more difficult to	feed.

       filename
	      This is the name of the file containing the antenna description.
	      It  is  expected	to  be	in a format created by either input or
	      first - two other	programs in the	Yagi-Uda project.  This	is  an
	      ASCII text file.

       iterations
	      is  an integer specifying	the number of iterations for the opti-
	      miser to perform to try to get the best antenna. Time will limit
	      the  number  you	choose.	 1000  iterations of a 1ele yagi takes
	      about 5 seconds, a 6ele approximately 60 seconds,	an 11  element
	      350  seconds, a 20 element 1030 seconds, a 33ele 2440 seconds, a
	      50element	5400 seconds, 100ele 21320 seconds all on an old 25MHz
	      486 PC with no external cache.  When using the -A	option the it-
	      erations is automatically	set internally so only one attempt  is
	      made.   When  using the '-t' and '-T' options, iterations	speci-
	      fies the number of iterations to attempt to get a	poorer design,
	      to  check	 the  sensitivity of the design	to small manufacturing
	      tolerances.

EXAMPLES
       Here are	a number of examples of	using optimise.

       1) optimise 5ele	1000

       Here the	file 5ele will be optimised using the default system for  1000
       iterations. The default might typically require gain, FB	and SWR	to all
       improve,	but this may be	changed	at any time. In	any case, the  program
       tells you what its optimising for. By default the program will only op-
       timise to the selected parameters are good, not over-optimising any one
       at the detrement	of the others.

       2) optimise -b30	-f50 -s2 5ele 1000

       This  is	similar	to above, but the boom can not extend by more than 30%
       from its	 original length, FB ratios above 50 dB	are considered accept-
       able,  as  are  SWR's less than 2:1. The	optimised resultant antenna is
       likely to have better FB	ratio, but poorer SWR than in (1) above.

       3) optimise -o1 5ele 1000

       This will simply	optimise 5ele for maximum forward gain.	The  resultant
       antenna	may have a poor	FB ratio and is	likely to have an unacceptably
       low input impedance and hence high VSWR.	This is	not  a	very  sensible
       method of optimisation.

       4) optimise -W49	-l7 5ele 10000

       This  will  optimise  the file 5ele using for 10000 iterations. It will
       require that the	weighted performance of	the antenna in three important
       parameters  (gain,  sidelobe level and SWR) improves from one design to
       the next. One or	two parameters can actually get	worst from one	design
       to  the	next, but the weighted performance is better. The positions of
       the elements or lengths of elements will	not change by more than	7%  in
       each iteration.

       5) optimise -g -S30 -G50	-F20 -p1500 5ele 10000

       This will optimise the file 5ele	using a	genetic	algorithm. 1500	anten-
       nas will	be randomly designed. The performance of each  of  these  will
       measured	 using	a 'fitness' function, weighted 30% to SWR, 50% to gain
       and 20% to FB ratio. The	probability of breading	from a pair of	anten-
       nas is proportional to the fitness function.

       6) optimise -w atv_antenna 10000

       This  will optimise the file atv_antenna	for a best average performance
       over a wide band. The progrram calculates the gain, FB and SWR at three
       frequencies, then computes an average (mean) performance	of the antenna
       over the	band. N	iterations will	take 3x	as long	to execute as N	itera-
       tions on	the same antenna without the '-w' option.

       7) optimise -t0.1 -T1  good_design 100

       This  will  take	 the  file good_design and make	100 different antennas
       from it,	to simulate the	effects	of building tolerances.	 Each  element
       is  assumed  to	be cut so that the mean	error of all elements is 0 mm,
       but a standard deviation	of 0.1 mm, so 68.4%  of	 element  lengths  are
       within  0.1 mm, 95.4% within 0.2	mm and 99.7% with in 0.3 mm. The accu-
       racy of placing elements	along the boom is much lower, so here we  have
       specified  a  standard  deviation  of  1.0 mm, so 68.6% of elements are
       placed within 1 mm of the correct position, 95.4% within	2  mm  of  the
       correct position	etc.  The program will report the *worst* performances
       achieved. If the	performance dips too mush, then	 you  either  need  to
       build them better, or get a design that's less critical!

STOPPING
       Optimise	 will stop after the number of iterations specified in the pa-
       rameter iterations.  It will also stop if a file	stop exits in the cur-
       rent  directory of the executable optimise This file can	of course only
       be created using	a multi-tasking	operating system such as Unix.	It  is
       *not*  advisable	 to  stop the program by hitting the DEL key (Unix) or
       CONTROL-C (DOS),	as one of the files may	be open	at the time, resulting
       in  an  empty  file.  Files  are	not open for any longer	than necessary
       (they are closed	immediately after writing to them), so this is	not  a
       likely occurrence, but can still	occur.

LIMITATIONS
       I'm  not	aware of any limitations, apart	from that filenames, including
       full path, can't	exceed 90 characters.

FILES
       filename		  Antenna description, created by input	or first.
       filename.up    Update file, listing achievements	of optimise.
       filename.bes	  Best file, containing	the best design	to date.
       changes	       File that causes	the program to pause to	re-adjust weights.
       stop	       File that stops optimisation process.

SEE ALSO
       first(1), input(1), output(1), yagi(1),	first(5),  input(5)  output(5)
       and optimise(5).

PLATFORMS
       Both DOS	and Unix versions have been built. The DOS version as distrib-
       uted requires a 386 PC with a 387 maths coprocessor.

       Although	I have altered the source to make it more compatible with  DOS
       (reduced	 file name lengths etc), my wish is to build a decent program,
       rather than fit the program to an outdated operating system.  If	 there
       is a *good* reason to use code that is incompatible with	DOS, this will
       be done.
       Since optimise takes  a while to	optimise an  antenna  (I've  optimised
       one  design  for	 a  week), it is obviously more	sensible to build this
       program under a multi-tasking operating system, as otherwise a  PC  can
       be tied up for days.

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  re-
       port them in such a way that they can be	easily reproduced.

       The  program  will  dump	core (crash) if	asked to optimise a 1ele beam,
       without any arguments.  This is because a 1ele beam  has	 no  parasitic
       elements	and by default the program only	changes	parasitic elements.

       Some  of	the options are	not checked for	sensible values, although most
       are now checked and report if they are out of range.

       If the user specifies very large	manufacturing errors  using  the  '-t'
       and  '-T'  options, its possible	for elements to	overlap	or for element
       lengths to become negative. This	will cause numerical errors. Any  rea-
       sonable values will not cause this.

       On  long	Yagi's (50 elements) optimise can go a bit silly. It can opti-
       mise say	a 1296MHz Yagi to get 20 dB at 1296 MHz, but less than 0 dB at
       only 1 MHz away.	Needs some thought!

       The  level  of  the sidelobes is	not computed with the GA or some other
       optimisation types. This	will be	corrected later.

       All those I don't know about.

AUTHORS
       Dr. David Kirkby	G8WRB (david.kirkby@onetel.net).  with help with  con-
       verting to DOS from Dr. Joe Mack	NA3T (mack@fcrfv2.ncifcrf.gov)

version	1.16			24 October 2000			   OPTIMISE(1)

NAME | SYNOPSIS | DESCRIPTION | AVAILABILITY | OPTIONS | EXAMPLES | STOPPING | LIMITATIONS | FILES | SEE ALSO | PLATFORMS | BUGS | AUTHORS

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