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                          YODA                      
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YODA - Dipole Radiation, ver.2.0, 1991
Z. Juricskay, Cs. Markus, P. Pacher, G. Mark
Physical Institute of the Technical University
H-1111 Budapest, Budafoki u.8. Hungary


     The YODA program is a visual aid  for  high-schools  and 
universities that can play  an  important  part  in  teaching 
physics.

     Demonstrating the radiation of  a  dipole  causes  great 
anxiety for teachers since it is really difficult to show the 
process of this occurence. Nowadays, animated "cartoons" seem 
to be the best way of demonstrating it.

     Our new program contains instructions and a full toolkit 
to make such films: it  uses  the  complete  equations  which 
describe the phenomena so it is  suitable  for  demonstrating 
the radiation in the near field as well as in the far one.

     The program has been divided into two parts: first,  the 
user is able to choose the options of the film and  -  before 
the lesson - make the movie. The program saves the ready-made 
phases on a disc and during the second part  it  can  re-play 
them as a film. If our "cartoon" is about  100  phases  long, 
the program can play it in 2 to 5 seconds so it  is  not  far 
from TV-quality!

     Before creating a film, several options can be  changed, 
for example:

  -  The dimension of the film. It is possible to make a film 
     that  shows  the  dipole  radiation  from  anywhere   in 
     three-dimensional space or as the  viewpoint  is  moving 
     round the antenna.
  -  The  quality  of  drawing,  which  can  be  HIGH, NORMAL 
     or LOW.
  -  The number of phases from 3 up to 100.
  -  The indicator of the phases. The  program  can  indicate 
     the time using a clock or simple numbers.
  -  The place of the antenna and the phase-indicator in  the 
     movie-window.
  -  The magnification (1 to 10) that chooses between the far 
     and the near field.
  -  For  creating  three-dimensional  films:  the   distance 
     between the antenna and the viewpoint, the angle of  the 
     line of sight.
  -  The  characteristic  of  the  field:   the   number   of 
     electrical and magnetic field-lines,  the  grid  of  the 
     Poynting-vectors and many other things.

     Working with the menu is easy: the movement of the MOUSE 
or the  UP  and  DOWN  keys move  the  highlighted  bar;  the 
  ENTER   key or the left button on  the  MOUSE  chooses  the 
menu-point which can give a new menu; the   ESC   key or  the 
right button of the MOUSE forces the program  to  leave  that 
new menu; and the   F1   button activates the HELP  anywhere. 
To leave the program, choose QUIT in the  FILE-MENU  or  just 
press   ALT   and   X   together.

     Watching a film you can use  UP  and  DOWN  key to  slow
down or quick up re-playing and  ESC  to leave  this  option.
Editing a text  LEFT , RIGHT , INSERT , HOME , END  functions
are available. To accept the string just press ENTER  and  to       
go back to last point press the  ESC  button.

     The  DIRECTORY  function is really easy-to-use:  LEFT  ,
RIGHT , PGUP , PGDN , HOME  and  END  functions help  you  to
find the file you are intrested in.      

     In addition the two main parts, there are several  other
features:

  -  The  file-operations  in  the  FILE-MENU  (load,   save, 
     delete).
  -  The HELP, which is changeable, so the user can place his 
     own experiences into it.

     The screen is divided into three main parts:
     
  -  the movie-window, which takes place in the middle of the 
     screen: drawing and re-playing can be seen here.
  -  the menus.  Their  place  is  changeable,  in  the  DEMO 
     version they are on the left side.
  -  icons descripting the new film.

     There are several icons showing the options of the  film 
(the number and the indicator of the phases, the  quality  of 
drawing), of the field (the  number  of  the  electrical  and 
magnetic  field-lines)  and  of  one  phase  (two  or   three 
dimensional, far or near field). 

     Any kind of inscription can be changed  easily,  because 
they can be found - with the EGA  and  VGA  colours  and  the 
whole structure of the MENU - in different files attached  to 
the program.

    The YODADEMO is a restricted version of  YODA,  only  the 
LOAD, PLAY, PLAY-FROM-MEMORY and - of course - QUIT  work  as 
described; other menupoints give their HELP by choosing them.

    System requirements:
    
          IBM PC, XT, AT or compatible computer
          at least 640 Kbyte RAM memory
          CGA, EGA (or VGA) or HERCULES graphics card
          a floppy drive or a hard disc
          MICROSOFT or compatible MOUSE (optional)
						
    YODA and the DEMO version is made by:
           
           Zoltn Juricskay   &   Csaba Mrkus

           Pcs,                  Srvr,
           Olga u. 13.            Szatmr u. 4.
           H-7632                 H-9600
           HUNGARY                HUNGARY

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