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Text File | 1991-11-24 | 26KB | 485 lines

MAPPER86/87 .. A DX MAP DRAWING and Propagation Program for IBM PC Compatibles with graphics capability. Version 7.1 by Dennis P. Murray 11165 McDonald Street Culver City, Ca. 90230 CompuServ 72770,2765 10 August, 1991 This program, written for BASIC compilers such as MICROSOFT QUICK BASIC or BORLAND TURBO BASIC, displays a map of the world centered on a user-selectable QTH, and does propagation predictions based upon one of 4 possible methods based upon modified MINIMUF 3.5 or MAXIMUF 3.0 methods. It shows the regions of sunlight and darkness around the world, and updates these regions automatically at user- specified time intervals. It can also accept arbitrary times and dates at the user option. The program accepts DXCC prefixes or latitude/longitude values for the DX location, draws the path from the home QTH to that location, and displays the range, azimuth and wave launch elevation angle from the home QTH. The user can select either short or long paths; the sunspot number; antenna height, gain, and polarization for both home QTH and DX station; transmit power; and the minimum wave launch angle to be used for propagation prediction. The propagation prediction gives the MUF (maximum usable frequency), LUF (lowest usable frequency) based upon E-layer screening, and the minimum number of F-layer hops for the minimum launch angle. Predictions of signal strength are made for Ham Band frequencies which include D-layer absorption, reflection losses, and transmit and receive antenna losses due to ground plane reflection at low elevation angles. This program is written for IBM PC compatible computers with a Graphics capability and color display. The program runs quite quickly on an AT clone with a hard disk and 640k of RAM, but it might be a 'dog' on a floppy-only machine because it must read some long files for the map data. The program is being uploaded in two versions, named MAPPER86 and MAPPER87. MAPPER86 is compiled using 'alternate math' option of the Microsoft BASIC 7.1 Professional Development System in order to use floating point computations under the Microsoft Binary Format which run much faster on machines without 80x87 math co-processors than do computations under the IEEE format supported by QBasic version 4.0 and later. MAPPER87 can be compiled under QBasic v 4.5 or BC7.1 using the IEEE floating point math option. It will run on machines with or without a Math Coprocessor, but it is very slow without one because of the lousy software emulation of the 80x87 routines which Microsoft has provided. The MAPPER86 version is strongly recommended if you don't have an 80x87. Both versions now support all graphics adapters ( CGA, EGA, EGA/Monochrome, MCGA, VGA, and HERCULES). If you want to use the Hercules mode you must first load the Microsoft Hercules driver MSHERC.COM which I have included in the package courtesy of Microsoft. Version 7.0 differs from earlier releases in that it has an extended DX Prefix list, uses a more detailed world map data file with a different file format than previous versions, and is somewhat more 'user friendly' about accepting input data. It also provides a facility for printing out a 24 hour summary of propagation conditions for a given path, together with a plot of the NUF over that period. An 80 column printer which recognizes a Form Feed command is needed for this option. Most importantly, Version 7 has added an entirely new method for propagation predictions based upon MAXIMUF 3.0, and allows the user to select whether the Maximum Useable Frequency ( MUF ) uses the ionospheric hops nearest to the transmitter and the receiver for its determination, or takes the worst MUF among all the hops along a multi-hop path. The author does not intend to support this software, but is simply releasing it into the public domain for non-commercial use by HAMS who know what they are doing with their computer. The BASIC source code is included for that reason. The following files are a part of the MAPPER system of files: 1- MAPPER86/87.BAS The Program Source Code Specific for Either Q-BASIC v4.5 or BASIC 7.1 PDS 2- MAPPER1.INC An 'INCLUDE' File Containing the beginning source code common to both versions. 3- MAPPER2.INC An 'INCLUDE' File containing most of the mapping source code common to both versions. 4- MAP-SUBS.BAS Source code for the propagation prediction calculations. 5- MAP-COM.INC An 'INCLUDE' File containing some COMMON and DIM statements needed by both code modules. 6- MAP-DEF.INC An 'INCLUDE' file containing function definitions needed by both modules. 7- MAPPER86/87.EXE the Q-BASIC 4.5 or BASIC 7.1 executable code. 8- MAPPER.ATL An Atlas of DXCC countries and their latitudes, longitudes, and DX prefix. This is an ASCII file ,sorted by prefix, which can be added onto by the user with a word processor or text editor. 9- PREFIX.ATL An Extended Atlas of country prefixes and their latitudes, longitudes. This file uses the official internationally designated prefix ranges to identify the country and permits identification of some of the more exotic DX call signs which have gotten more common. This is an ASCII file ,sorted by prefix, which can be added onto by the user with a word processor or text editor. 10- MAPPER.DEF A short file used to store some default values used by the program. 11- MAPPER.DOC This instruction file. 12- WORLD.All A large file containing the lat/lon of the world's borders. This is used to recompute the map whenever the map center point is redefined. 13- MSHERC.COM A Microsoft program to permit the use of a Hercules video adapter with MAPPER87. It must be executed prior to executing MAPPER87. This option is not available for MAPPER86 because that version is compiled under Quick Basic Version 3 which did not support Hercules video. 14- MAPPER1/2.SCR Large files which are used to store and retrieve the screen data for a world map centered on the user's location. These files are not supplied in the .ARC files but created by the program when it is first used and they are rewritten whenever the user changes the 'Home' location. ( It is interesting to view the world as seen from DX locations.) This data is read into a large array in memory to permit rapid redrawing of the map as the sun moves. The file is written into the integer array NSTORE by BLOAD and BSAVE commands. Because the program uses a lot of memory to speed things up, this array is DYNAMIC and does not generally reside in the normal BASIC data segment. 15- SEA-MAP.DAT A data file which contains a raster map of the world's oceans in a bit-map format in 1 degree intervals of latitude and longitude. This file is read into an array when the program is started. It is used to determine whether propagation 'bounce' points are on land or sea in order to compute the correct terrain reflection loss for that hop. To accommodate different uses I have broken the file set into three ARC distribution files: 1- MAPR86.ARC is intended for those who only want to operate MAPPER86 and who don't have math coprocessors. It contains the following files: MAPPER.ATL MAPPER.DEF MAPPER.DOC MAPPER86.EXE MSHERC.COM PREFIX.ATL WORLD.ALL SEA-MAP.DAT 2- MAPR87.ARC is intended for those who only want to operate MAPPER87 and who do have math coprocessors. It contains the following files: MAPPER.ATL MAPPER.DEF MAPPER.DOC MAPPER87.EXE MSHERC.COM PREFIX.ATL WORLD.ALL SEA-MAP.DAT 3- MAPPER.ARC is intended for those who are interested in studying, modifying, customizing, or recompiling the MAPPER program to suit their own purposes. It contains the source code files for the MAPPER system: MAPPER.DOC MAPPER1.INC MAPPER2.INC MAPPER86.BAS MAPPER87.BAS MAP-SUBS.BAS MAP-COM.INC MAP-DEF.INC The author encourages the distribution of this program to anyone who might find it useful, or onto bulletin boards which deal with HAM radio or shortwave listening. Please make sure to include ALL the required files for one of the ARC distribution sets described above in any uploading however. INSTRUCTIONS: To run this program simply enter 'MAPPER86' or 'MAPPER87'. After an initial message explaining the program is displayed, and you press any key to proceed, you will be presented with a 8-choice initial menu which allows you to change the default values of: 1- Sunspot number 2- Home QTH latitude and longitude 3- The time interval at which the daylight/darkness areas are redrawn. 4- Transmitter power output. 5- Minimum elevation angle for propagation predictions. 6- Graphics Mode 7- Method for Propagation prediction. 8- Change or View the Set of Frequency Bands, and the antenna heights, gains, and polarizations for each band. This will drop you into a submenu which permits your custom definition of up to 10 Bands of interest, together with antenna parameters for both home and DX stations. SWLs may want to use this feature to change the frequency set to their favorite HF Broadcast bands. Pressing the appropriate number key will put up prompts to allow changes to these variables, and will return you to this menu after a change is entered. (Important: Make sure you select the proper display type for your machine at this menu when you first run it. This package will have a file of my own default values for the parameters in this menu, and they are unlikely to be the correct values for your machine.) After you have made the appropriate changes pressing <ENTER> at the menu prompt will store these new values in the MAPPER.DEF file and proceed on to the map drawing. The map drawing will first put up a blank box, then calculate the position of the sun at the time and date currently held by the DOS, draw the solar terminator ( it looks like a satellite ground trace ), and color the sun-lit portions of the world in red. It will then go on to draw the country boundaries, color the oceans blue, and color the USA green. The land areas which are in darkness will show up in black. The program may miss coloring part of the oceans blue because of the position of the solar terminator blocking the PAINT commands used in the subroutine at line 8000 ... . I got tired of adding ocean points to this routine to cover all the contingencies. After the map is drawn a Menu bar will appear on the bottom line of the screen, with 9 choices selected by the function keys: f1- Select DX Prefix. You will be prompted to enter a DX prefix ( eg. ZS for S. Africa ). The program will then search the DX atlas for an occurrence of this prefix. It will display all of the entries ( ie ZS1,ZS2,... ) that contain this string and ask you to select one. If the number of candidate entries is large you can simply <ENTER> to continue the search. When a selection is made the program will fetch the location of the prefix, make a propagation prediction for the currently selected date and time, draw the path from your QTH to that location, and display sundry useful information at the top of the screen. On the left of the screen the signal strength predictions will be shown for all Ham bands for which the frequency is more than 80% of the lowest usable frequency (LUF), less than 120% of the maximum usable frequency (MUF), and whose predicted signal strength is higher than -20dB relative to 0.5 microvolts into a 50 ohm receiver input. For each band which meets these criteria I display the frequency, the absorption losses (Labs), the ground reflection losses (Lref), the transmit and receive antenna losses due to ground reflection ( Ltx, Lrx ), and signal strength ( Prcv ). The losses are given in dB. The signal strength is given in dB relative to 0.5 microvolts into 50 ohms. This is about an S-1 signal level for most Ham receivers, and S-9 usually corresponds to 50 microvolts at the antenna terminals. Thus a signal strength of 40 dB would correspond to a S-9 prediction. The user should be cautioned that the signal strength predictions are very uncertain. I only calculate paths via the F2 layer, and there a great number of other propagation modes possible which may be better or worse than the pure F2 mode. Don't blame the author if this program says that you can't possibly work Australia when you are hearing VK's with S-9 signals. These are only crude indications of the likelihood of a path being open. f2-Specify Country Name. Same as option 1 except that you are prompted for the name of a country ( or a subset of that name such as 'AUS', which will find both Austria and Australia ). The search process is insensitive to the case of your entry. f3-Specify Lat/Lon. Same as the above option except you will be prompted to enter the latitude and longitude of the desired DX location. f4-Select Date/Time. Prompts for a new date and time to be used to calculate solar terminator and make propagation predictions. <ENTER> responses to either of these prompts will fetch the current DOS value of date or time. This option will also turn off the automatic updating of the terminator and map redraw. f5-Use Real Time. This option will reset the above option to the real (DOS) date and time and enable the auto update feature. f6-Toggle Between Short and Long Path. This toggles the path from the long path option back to short path and vice-versa f7-Change Parameters. This returns you to the 7 choice initial menu to change the various default parameters such as sunspot number, antenna heights, power, etc. f8-Toggle Printed Output of 24 hour Propagation Predictions on or off. When F8 is hit for the first time it 'toggles' this function on and subsequent hits turn the option on and off in sequence. When this option is 'on' it prints out the same information on propagation that is displayed on the screen, but does it for an entire day at one hour intervals, and plots a graph of the MUF versus time. The printing starts when you select a new DX location, not immediately after the function is toggled on. f9-Quit. Exits the program and returns you to DOS. The program is entirely menu-driven so you don't have to remember any special commands to use it. Good luck!! Instructions for recompiling: Some of you may wish to customize this program in some way, so I have included the BASIC source code. If you make changes you will have to recompile and LINK the code. The following instructions may help you. If you have a math coprocessor or if you don't care how slow the program runs then compile using BASIC PDS 7.1 or Quick-Basic 4.0 or later: Compile and LINK Using the following command lines: BC MAPPER87/D/X/O/V; <Rtn> BC MAP-subs/D/X/O; <Rtn> LINK MAPPER87+MAP-SUBS; <Rtn> If you don't have a coprocessor and you want faster execution then compile using BASIC PDS 7.1 with the /FPa (alternate math package option). BC MAPPER86/D/X/O/V/FPa; <Rtn> BC MAP-SUBS/D/X/O/FPa; <Rtn> LINK MAPPER86+MAP-SUBS; <Rtn> This program is totally incompatible with the BASIC Interpreter which IBM and Microsoft supply with their DOS. (i.e. BASICA of GWBASIC ). There is not a prayer of making it run under the interpreter. Some Technical Information: The propagation calculations are based upon either the MINIMUF 3.5 method or the MAXIMUF 3.0 method, but with many modifications by this author. I am indebted to Robert R. Brown, NM7M, for providing me with the MAXIMUF 3.0 method for MUF calculation. I had been trying (unsucessfully) since Version 2 of this program to obtain this method because it has been evaluated as the most accurate PC-based method in comparison with IONCAP ( The elaborate Ionospheric model developed by the Institute of Telecommunication Sciences in Boulder, CO. which is normally used as a standard of comparison). The method is due originally to Raymond Fricker of the BBC External Services. Its key element is a mathematical model for the vertical incidence sounding frequency obtained by noting that the ionosphere mainly depends upon the solar zenith angle and geomagnetic latitude. He then did a curve-fit of the the CCIR Report 340 vertical sounding frequency to the function Fv= A*Cos( B*(T-C) )* Cos ( Z+D))^0.5 where T is the local time, Z is the geomagnetic latitude, and A,B,C,D are 'constants' which depend upon Sunspot number and season of the year. Having obtained the main dependence in this form, he the went on to derive a set of 20 'correction' terms to improve the fit. The method also uses a curve-fit to the virtual height of the F2 layer. The method's equations can be obtained from examination of the Subroutine CRIT.FREQ in the MAP-SUBS.BAS source code. I have made a number of enhancements to the 'standard' propagation calculations: 1- The 'standard' CCIR method for hand-calculating MUF uses only the first and last ionospheric bounce points ( the two control point method ), This method is available in MAPPER. In addition, I have provided the user with the option to let MAPPER evaluate the MUF at every hop and select the worst-case condition out of all of them. This results in more pessimistic MUF and LUF estimates than the endpoint method because conditions over parts of the total path may be much different than conditions at only the ends of the path. A path with a hop near the near the North pole is an important example. I leave it to the user to try the various methods and see which works best for you. I would be interested in any results you care to share. 2- I have included the E-layer screening frequency and lowest- usable frequency ( LUF ) estimation technique given in chapter 4 of 'Amateur Radio Software ', by John Morris GM4ANB , RSGB Books, Lambda House, Cranborne Road, Potters Bar, Hertfordshire EN6 3JW. The subroutine starting at line 45000 contains this calculation. 3-I have used what apparently is the HAM convention for longitudes being positive-West for the input and output in this program, in the PROPAGATE subroutine, and in the DX Atlas file MAPPER.ATL. However, in the internals of the program I immediately reverse the sign of the longitude. Being an engineer by training I think in terms of right-handed coordinate systems! Therefore those who want to modify the program should be wary of the sign of the longitude being used. 4-Note that I have changed the names of the variables in the MINIMUF subroutine from the standard values to names which are descriptive of what the variable actually is. 5-I have augmented the propagation predictions with a signal strength prediction. For each ionospheric control (bounce) point an estimate of the D-layer absorption is made according to the method in chapter 5 of Davies, "Ionospheric Radio Propagation", NBS monograph 80, 1965. The total D-region absorption is summed up for all control points. The subroutine at line 46000 contains this calculation. 6-In addition, a calculation of the loss due to ground reflection is made for each ground reflection point along the path. At each of these points the array SEA-MAP is decoded for the reflection point location and if it is a sea point then the reflection coefficient for sea water is calculated ( dielectric constant of 80, conductivity of 4 mho/m ). If the reflection point is over land then a dielectric constant of 4 and conductivity of 0.01 mho/m are used. The Fresnel reflection coefficients for both horizontal an vertical polarization are power-averaged to account for the random polarization of the wave due to Faraday rotation at HF frequencies. I have also modified the reflection coefficients to account for surface roughness. A RMS surface roughness of 4m is used on the sea, and 15m for land points. The subroutine REFLECT at line 41000 of module MAP-SUBS makes the reflection calculations. 7-To account for the fact that most Hams have fairly low antenna heights, thus suffer large losses at low elevation angles, I explicitly calculate the multipath cancellation losses for each antenna in the subroutine MULTIPATH at line 42000 in MAP-SUBS.BAS. This is the standard Fresnel reflection calculation without surface roughness included. Most urban locations will be worse than this calculation suggests because buildings in the foreground will actually shadow the low angle line-of-sight and modify the reflection area. If you know you have poor line-of-sight you should modify the minimum launch angle setting at the initial menu appropriately.