                                  ES-PROP
                      Sporadic-E Propagation Analysis
                        version 1.4 - November 1994
                            James M. Roop, K0BI

1    INTRODUCTION
     
1.1       ES-PROP is a graphic sporadic-E analysis program that permits
          the analysis of Es MUF's and paths.  The user inputs observed
          frequency and path endpoints.  The program calculates the MUF
          for the maximum Es path length (which is typically 2300 km for a
          Es cloud height of 105 km.)  The program also displays, on a map,
          the path of the observed endpoints, the calculated location of the
          Es cloud (the control point) and the loci of minimum distances
          around the control point for operating frequencies within the VHF
          amateur bands.  The program will also attempt to analyze a 2-hop
          sporadic-E path.  The program will also predict a target endpoint
          for a given control point and path starting point.

1.2       Path endpoints are generally entered as Maidenhead grid squares
          (4 or 6 characters).  Endpoints may be entered manually or with
          a mouse. When using a mouse, the current grid square (and
          geographic coordinates) of the mouse cursor is displayed on the
          screen to allow accurate placement of the path endpoints.

1.3       ES-PROP is based on the article: Emil Pocock, "Sporadic-E
          Propagation at VHF: A Review of Progress and Prospects", QST,
          April 1988.  Version 1.4 corrects problems with the calculation of
          the maximum single-hop distance MUF that exists in earlier
          versions of ES-PROP.  Earlier versions calculated a much higher
          MUF that can exist.  Thanks to Pat Dyer, WA5IYX, for pointing out
          the problem.

1.4       The program ES-PROP is copyrighted with all rights reserved by
          the author.  However, ES-PROP, version 1.4 may be freely used. 
          The program may also freely distributed as long as no profits are
          realized.

2    SYSTEM REQUIREMENTS

2.1       An IBM compatible computer with at least an EGA display card
          and RGB monitor is required.  A mouse is required for full
          functionality.  A math coprocessor is also recommended.

3    STARTING THE PROGRAM

3.1       The following files are required ES-PROP, version 1.4:
 
               ES-PROP.EXE    the executable program
               MAP.ESP        map file
               
               
3.2       Generally, the program files should be in the same sub-directory. 
          To start the program, change directory to the appropriate sub-
          directory and enter: 
     
               es-prop <CR>

3.3       The program will load and display the map with the file name
          "MAP.ESP".  ES-PROP supports screen mode 8 (640 X 200) and
          screen mode 9 (640 X 350).  The type of screen mode used
          depends is determined by the map file.  Generally one of the
          distributed map files will be copied into "MAP.ESP."  
3.3.1               The distributed mapfiles (except for MAP.ESP) have base
                    file names that end with either an 8 or 9.  Files with the
                    numeral 8 are screen mode 8 map files and files with the
                    numeral 9 are files for screen mode 9.  Screen mode 8 is
                    used for older systems with only an EGA display card and a
                    RGB monitor.)

3.3.2               Map files, other than the default MAP.ESP, may be selected
                    from the command line by entering, for example:
               
                         es-prop USAMAP9.ESP <CR>

3.4       The program will detect the presence of a mouse.  If a mouse is
          detected, the program will display the map and a mouse cursor
          will be present.  The upper-lefthand corner will display the
          geographic location and grid square for the location pointed to by
          the mouse cursor.  If a mouse is not detected, the program will
          start and prompt for the manual input of the first path endpoint.

4    USING THE PROGRAM

4.1       Definitions

4.1.1               Entry screen (mode)
                    The screen where a mouse cursor is displayed in the
                    entry screen and the geographic location and grid
                    square of the mouse cursor is displayed above the
                    map.  

4.1.2               Options screen (mode)
                    The screen in which options such as clearing the map,
                    eliminating iso-MUF lines and changing the virtual
                    height of the Es are available form this screen.

4.1.3               Endpoint setting mode
                    The mode where path endpoints and observed MUF
                    are entered.  See paragraph 4.4.4.1.


4.2       The program displays on screen prompts and information to help
          use the features of the program.

4.3       The programs displays two different basic screen types, an
          options screen and an entry screen.

4.3.1               The left portion of the top line of the options screen appears
                    as:

                    Quit  Eliminate iso-MUF  Clear map  Predict path  +/- h' 

               See section 4.7. 

4.3.2               The left portion of the top line of the entry screen displays
                    the geographic location and grid square of the location
                    pointed to by the mouse cursor.  If a mouse is not detected,
                    then the left portion of the top line is blank.  See section 4.4.

4.3.3               The program starts in the entry screen if a mouse is present. 
                    If a mouse is not present, the program will start in the
                    endpoint setting mode (see section 4.5.)

4.4       Entry Screen with Mouse

4.4.1               Quitting the program

                    To quit the program, type  "q".

4.4.2               Switching Screens

                    To switch to the information screen, type  "<Esc>".

4.4.3               Mouse Buttons

4.4.3.1             The right mouse button is used to enter the path
                    endpoint setting mode (see paragraph 4.4.4.1.)  When
                    in the path endpoint setting mode, the right mouse
                    button will cancel the operation and return the entry
                    screen (see paragraph 4.4.4.3.)

4.4.3.2             The left mouse button is used to enter a geographic
                    location.  When pointing to a control point location, the
                    clicking the left mouse button will return MUF
                    information of the selected point. When in the path
                    endpoint setting mode, the left mouse button will set
                    the ends of the observed path and allow entry of the
                    observed frequency. 
  
4.4.4               Entering Observed Path Information

4.4.4.1             The current location of the mouse is displayed on the
                    top line.  To enter the endpoints of an observed
                    propagation path, click the right mouse button.  The
                    geographic information on the top line is cleared and
                    a prompt for the first grid square appears below the
                    map.  The prompt line shows the grid square location
                    of the mouse cursor.  Point the mouse to the desired
                    location and then click the left mouse button.  A
                    prompt appears for the second grid square.  Select
                    the second endpoint with the left mouse button.  A
                    prompt to enter the observed frequency appears
                    along with two lines containing frequency input
                    prompts.  The upper line is a frequency line between
                    25 and 300 Mhz with the locations of the FM and low
                    VHF TV bands and the 6, 2 and   meter bands
                    indentified.  The lower line displays 50, 144 and 222
                    MHZ.  The observed frequency band can be selected
                    by pointing  to the appropriate frequency band on the
                    lower  line and selecting it with the left mouse button
                    or it can be selected by pointing to the appropriate
                    frequency on the upper line.  When the cursor is
                    pointing to the upper line, the frequency that the
                    cursor is pointing to appears to the left.  Select the
                    desired frequency by clicking the left mouse button. 
                    When the mouse cursor is removed from the upper
                    line, the indicated frequency disappears.

4.4.4.2             The MUFfor  the maximum distance single-hop path
                    is calculated and displayed below the map.  The
                    calculated MUF will be less than or equal to the actual
                    MUF depending on whether the observed path for the
                    observed frequency was the minimum distance that
                    the level of E-layer ionization could support.  The
                    great circle path between the two endpoints is drawn
                    on the map.  The loci of points that are one-half the
                    possible path length at the MUF (iso-MUF's) from the
                    control point for a given virtual height of the Es is
                    drawn on the map.  Finally the iso-MUF's for the
                    approximate minimum distances from the control point
                    at operating frequencies of  50, 144 and 222 MHz are
                    drawn; the program assumes that the minimum path
                    length was entered for the observed frequency.   After
                    the map has be updated, the program display the
                    options screen.  To return to the entry screen, press
                    any key that is not an option (such as the space bar)
                    or click the left mouse button.

4.4.4.3             To abort the endpoint setting mode press either the
                    right mouse button or press "<Esc>".

4.4.5               Manually Entering Path Information

4.4.5.1             The path endpoints and frequency of observation can
                    be manually entered by pressing any key while in the
                    entry screen mode.  (If in the path endpoint setting
                    mode, press "<Esc>" to exit and then press any key.

4.4.5.2             Prompts for path endpoints and observed frequency
                    will appear.  Map information will be drawn as
                    described in paragraph 4.4.4.2.

4.4.5.3             To abort manual entry, do not enter any path endpoint
                    grid square information and press <Enter>.

4.5       Endpoint Setting without Mouse

4.5.1               If a mouse is not detected upon program startup, the
                    program starts in the endpoint setting mode.  See paragraph
                    4.4.5.2.

4.5.2               The Predict Path option will not be available from the
                    options screen.

4.6       Showing Information about a Control  Point

4.6.1               Pointing to a control point and pressing the left mouse
                    button will display the MUF for the control point.  If the
                    distance loci lines have be eliminated, then the lines will be
                    redrawn.  The mouse cursor must be within 300 km of the
                    control point when the left button is pressed and the closest
                    control point will be selected.  Information for 25 control
                    points can be stored.

4.7       Options Screen

4.7.1               The following options are available from the options screen:

4.7.1.1             Quit the program - press "q".

4.7.1.2             Eliminate iso-MUF - press "e".  The map is cleared of
                    the iso-MUF's, however the control point locations are
                    still displayed.

4.7.1.3             Clear map - press "c".  The map is cleared and all
                    control point data is cleared.

4.7.1.4             Predict path - press "p". See paragraph 4.7.2.

4.7.1.5             +/- h' - press "+" or "-" to change the virtual height of
                    the Es cloud.  Heights of 95, 100, 105, 110 and 115
                    km can be selected. The default virtual height is 105
                    km.  The current virtual height that the program is
                    using is displayed in the upper righthand corner of the
                    display. If a control point is entered at a given virtual
                    height and the virtual height is changed, then when
                    information about the control  point is redisplayed (see
                    paragraph 4.6.1), the distance loci drawn on the map
                    reflect the new virtual height.

4.7.1.6             Switching to the entry screen

                    The entry screen is entered by pressing any key other
                    than one of keys used for the options, i.e., for
                    example, the space-bar.

4.7.2          Predicting paths

4.7.2.1             The endpoint grid squares for different paths for a
                    selected control point can be determined.

4.7.2.2             Press "p" from the options screen.  "Select point"
                    appears in the upper righthand corner of the display.

4.7.2.3             Point to the desired control point with the mouse
                    cursor and press the left mouse button.  If the
                    distance loci have been eliminated, then they will be
                    redrawn.  The "Select point" prompt will clear and the
                    grid square and geographic location pointed to by the
                    mouse cursor will be displayed in the upper righthand
                    corner of the display.

4.7.2.4             Point to the desired starting path endpoint and press
                    the left mouse button.  The great circle path will be
                    drawn and the two endpoint grid squares will be
                    displayed.


5    ASSUMPTIONS

5.1  This program makes a number of assumptions.  MUF and distance
     calculations are made assuming that there is a flat ionosphere over a
     flat earth.  Single Es cloud paths are also assumed.  A number of other
     assumptions have been made in trying to characterize paths other that
     single hop.

