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1994-11-20
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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.
