HamCall (October 1991)

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.op M A Radio Wave Propagation Prediction Program for Irregular Terrain Version 3.1 Miles A. Merkel 1 December 1988 Approved by:_/S/__2 JANUARY 1989__ Elizabeth J. Merkel Title: President, QO Inc QO INC 2240 Golf Links Road Sierra Vista Arizona 85635 This page left intentionally blank .FO ii M A Radio Wave Propagation Prediction Program for Irregular Terrain Version 3.1 by Miles A. Merkel December 1988 .FO iii LICENCE No version of M, including version 3.1, is public domain soft- ware, or free software. M is a work copyright (C) 1989 by Miles A. Merkel. Non-registered users are granted a limited license to use M on a trial basis for the purpose of determining whether M is satisfactory for their use. Use of M, except for this limited purpose, requires registration. Use of non-registered copies by any person, business, corporation, governmental agency or other institution is strictly forbidden. Registration permits a user a licence to use M only on a single computer. A registered user may use the program on a different computer, but may not use the program on more than one computer at the same time. No user may modify M in any way, including but not limited to reverse compile, dissassembling or otherwise reverse engineering the program. All users are granted a limited license to copy M only for the trial use of others subject to the above limitations, and the following conditions: 1. M must be copied in unmodified form, complete with license information. 2. Full M documentation must be included with the program. No fee, charge or other compensation may be collected for dis- tribution by any licensee. 3. M may not be distributed in conjunction with any other pro- duct without prior written permission. Operators of electronic bulletin board systems may post M for downloading by their users only when the above conditions are met. Distributors of public domain or user supported software may distribute copies of M subject to the above conditions only after obtaining written permission from Miles A. Merkel. .fo iv WARRANTY Miles A. Merkel makes no warranty of any kind, express or implied, including, without limitation, any warranties of merchantability and/or fitness for a particular application. Miles A. Merkel shall not be liable for any damages, whether direct, indirect, special or consequential arising from a failure of this program to operate in the manner in which the user desires. Miles A. Merkel shall not be liable for any damage to data or property which may be caused directly or indirectly by use of the program M. In no event will Miles A. Merkel be liable to the user for any damages, including lost data or other incidental or consequential damages arising out of the use or inability to use the program M, or for any claim by any other party. .fo v PREFACE Version 3.1 of M has been compiled using the Microsoft FORTRAN 77 version 3.31 compiler. M is intended for use on any IBM PC, XT, AT, or compatible with at least 256K of memory, DOS 2.0 or higher, and a color/graphics adapter (CGA), enhanced graphics adapter (EGA), Hercules board or equivalent. In the interest of configuration control and compatibility with future releases, I am not releasing the source code; however, any user with specific requirements will be cheerfully accommodated. .FO vi ACKNOWLEDGEMENTS M was assembled, written, coded into FORTRAN 77 and compiled as a singular effort, encompassing a number of years; however, I take no credit for the superb efforts of researchers who have gone before, and feel compelled to list the major sources which were researched. I pulled on many references to accomplish the implementation of M. The single most important reference, providing the basic framework of M, was the Rice,P.L., Longley,A.G., Norton,K.A., and Barsis,A.P., classic, "Transmission Loss Predictions for Tropospheric Communication Cir- cuits". The second most important reference was the Longley,A.G., Rice,P.L., Prediction of Tropo- spheric Radio Transmission Loss Over Irregular Terrain, A Computer Method - 1968". The third most important reference was the Hufford,G.A., Longley,A.G., and Kissick,W.A., "A Guide to the Use of the ITS Irregular Terrain Model in the Area Prediction Mode". Other researchers works were called on to vary- ing degrees, e.g., Askne(1987), Ayasli(1986), Bean, et.al, (1960), Cavalcante(1982), Hill (1980,1981), and the list goes on, much too long to reproduce here and the reader is referred to the open literature. I wish to mention one private communication in which G. Hufford informed me of an improvement he has implemented in the point-to-point pre- diction technique. .FO vii M an Irregular Terrain Radio Wave Propagation Prediction Program INTRODUCTION This document is a very abbreviated explanation of how to access the functions of M. As mentioned in the PREFACE, Version 3.1 of M is intended for use on any IBM PC, XT, AT, or compatible with at least 256K of memory, DOS 2.0 or higher and a color/graphics adapter (CGA), enhanced graphics adapter (EGA), Hercules board or equivalent. One additional requirement is the inclusion of DEVICE = ANSI.SYS in a CONFIG.SYS file. This is needed for use by the ESCAPE sequences in the program. If you do not already have this, simply type (assuming you are using a hard drive): C: COPY CON CONFIG.SYS <RET> DEVICE = ANSI.SYS <RET> ^Z <RET> Your system will inform you: 1 FILE COPIED Your CONFIG.SYS file should, of course, contain other entries, and I refer you to your DOS manual for a full explanation. A copy of the ANSI.SYS has been included on your M disk for con- venience. This file is, or should be, included on your DOS master disks. If you observe strange things, e.g., the screens do not look "right", you see strange symbols that don't appear to belong (a small arrow pointing left followed by a left bracket), M is not able to access the ANSI.SYS file and you may need to seek help. DISCUSSION Assuming you have followed the instructions in the introduction faithfully, loaded your M DISK in DRIVE A and gotten a DOS A:\> prompt, or whatever you use for a prompt, simply type "M" (with- out the quotes) and <RET>. The screen shown in Figure 1 should appear as white printing on a blue background. Pressing <RET> should result in the screen shown in Figure 2. At this point, I give you the choice of reading five screens of introductory words, or going directly to the input of data for a prediction. I advise that you at least skim through these pages to give you an insight into what the Radio Wave Propagation Engineer does, in very general terms, to provide a projection, usually referred to as a prediction. They may be skipped later. .FO 1 * * * * * * * * * * * * * * * * * * * * * * * * * * * * M * * * * THE TECHNIQUE * * * * M is a technique ready to assist you in the analysis * * or design of your tropospheric communication system. * * * * M is friendly...you only have to know how to read !! * * * * M provides you with predictions of long-term median * * transmission loss over IRREGULAR terrain in the 20 * * MHZ to 20 GHZ frequency range. * * * * M is an interactive version of the LONGLEY-RICE pre- * * diction model updated with very recent research work. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Pause. Please press <RET> to continue. Fig. 1. First screen of introductory words in M. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * MILES * * PURVEYOR OF CRYSTAL BALLS * * * * Welcome to the wide world of Radio Wave Propagation. * * * * My name is Miles (like in Per Hour) and in the next * * few minutes I will be taking you by the hand through * * the maze of Atmospheric and Terrestrial Physics. * * * * Before we begin, you can reach me (just in case) at: * * * * Miles A. Merkel Phone (602) 458-4580 * * 2240 Golf Links Road * * Sierra Vista, AZ 85635 Copyright 88 Merkel * * * * * * * * * * * * * * * * * * * * * * * * * * * * * M for More words, P for Proceed with Predictions, Q for Quit (Heaven Forbid) Fig. 2. Second screen of introductory words in M. Your introductory screen to your inputting of data looks like: You are at the Threshold...Ready???(Y/N)(or CODE): .FO 2 For the moment you will ignore the "(or CODE)" and type "Y" <RET> and the screen will change to: Do you want your output to have your own TITLE ? You may enter either Y for Yes with <RET> or you may enter N for No with <RET>. If you elect Y for Yes, you will be prompted: I am allowing you 50 spaces for your TITLE. Please keep within the limits as shown below: ^START ^10 ^20 ^30 ^40 ^50 You may now type in the title you wish to appear on your output data sheet. If you do not wish to type in a title (select N for No) a title will be supplied for you. Your next screen in this data request sequence will appear as: Enter your communication link distance in KM: I use the Metric system throughout, so if you think in feet and miles, get out your conversion chart and a pocket calculator inches x 2.54 = centimeters feet x .3048 = meters 5280 feet = one (1) US Statute mile 1000 meters = one (1) kilometer There, I'm not such a bad guy after all. Don't worry about decimals (e.g., enter 6 or 6. for the same result) unless you are inputting the decimal part of a parameter (e.g., 6.8 km). Don't forget the <RET> each time. That gives you a chance to change your mind, or hit a wrong key, before the program eats your input. Your next screen will be as shown in Figure 3. Notice I only gave you the border of stars in the introduction ? At this point I will be asking for a number of inputs relating to environmental factors. First is what I call a climate code: 1 is EQUATORIAL 2 is CONTINENTAL 3 is MARITIME SUBTROPICAL 4 is DESERT 5 is CONTINENTAL TEMPERATE 6 is MARITIME TEMPERATE OVERLAND 7 is MARITIME TEMPERATE OVERSEA Select one of these and enter 1, 2, 3, 4, 5, 6, or 7 If you are not sure what code to use, select 5. Fig. 3. Climate code selection screen in Program M .FO 3 If you have been paying close attention so far and following the prompts carefully, you should be at the screen shown in Figure 4. Now I need some idea of how rough, or irregular, terrain is in the area of your communication link. The parameter is called "DELTA H" and is measured in METERS. You may select a value from the following table: TERRAIN DESCRIPTION DELTA H ( in Meters) ------------------- -------------------- water, or Very smooth plains 0 - 5 smooth plains 5 - 20 slightly rolling plains 20 - 40 rolling hills 40 - 80 hills 80 - 150 mountains 150 - 300 rugged mountains 300 - 700 EXTREMELY rugged mountains > 700 Pick a value from this table and input it now: Fig. 4. Terrain roughness factor in Program M. Your next screen will be as shown in Figure 5. I need to compute the EFFECTIVE EARTH RADIUS. To do this I will require two input parameters: First, the AVERAGE ELEVATION of your communication link above SEA LEVEL (ARITHMETIC MEAN described in the introductory screens) and; second, the MINIMUM MONTHLY MEAN SURFACE REFRACTIVITY (N(0)) for your link, referred to mean sea level (from published tables, or the next version of M). You may input these values yourself, or I can provide them for you. Do you want ME to provide them ? (Y/N) Fig. 5. EFFECTIVE EARTH RADIUS computation in Program M. In view of the fact that many of you may not understand these parameters, I give you the option of accepting reasonable default values of ZSYS = 0 (sea level) and N(0)) = 301., respectively. If you type Y and <RET>, these values are entered automatically, and the M input procedure takes you to the next input. If you elect to input the values yourself by typing N and <RET>, I still give you the option of: .FO 4 You have chosen to input your own values, so I will ask for them now, but I will give you the out: C to CHANGE your mind and let me do it for you, G to GO on and input the values yourself. If you persist by entering G to GO, followed by <RET>, you get: Enter your ARITHMETIC average path elevation in meters: and after entering this value, <RET> will get you: Enter your MINIMUM MONTHLY MEAN SURFACE REFRACTIVITY: An experienced Propagation Engineer will know these values for his communication path, or will know where to obtain them. The next version of M will contain screens providing further information on these parameters along with recommended values good for your area of the world. As you may have noticed by now, I have been with you every step of the way. Every time you enter a value that M cannot use (the value you entered was out of the range of values valid for the prediction technique) M simply told you that your input was not correct and backed up to allow you to input an acceptable value. Your next screen will prompt you for the electrical properties of the ground along your communication path: I believe there are only two more things needed: EPSILON, the Permeability of the Earth, and SIGMA, the Conductivity of the Earth. Do you want me to input EPSILON for you ? Y/N N Enter your value of EPSILON : 15 Do you want me to input SIGMA for you ? Y/N N Enter your value of SIGMA : .005 Here I have reproduced the entire sequence of question/answer in a sequence you might choose. (Notice I have conveniently placed your responses over at the left margin.) Had you chosen to accept my values, you would have gotten 15. and .005, respective- ly. These are values which have proven to be reasonable under most circumstances. Once again, the next version of M will provide you with a suggested range of choices of these values. .FO 5 Your next screen will show you: I lied...You have to provide more input data. For starters...Your antenna polarizations. For the time being, I am not allowing mixed polarization, that is, I only allow the same polarization for both transmit and receive antennas in the following format: 1 = Vertical Polarization 0 = Horizontal Polarization You may enter Polarization now (0/1) : Your next screen will appear like this: I need SITING criterion for the antennas on your link. I will give you just three to pick from: 0 = RANDOM SITING 1 = CAREFUL SITING 2 = VERY CAREFUL SITING OK...Give me a 0, 1, or 2 for SITE 1: 0 Now, give me a 0, 1, or 2 for SITE 2: 0 You will note that, again, I show you the entire screen in a sequence of question/answer that you might use. SITING is how well you pick out where your transmitter and receiver are located, or SITED. If one of your antennas is mounted on a mobile vehicle, you probably have little, if any, choice of where you are SITED and hence you have RANDOM SITING (0); however, if one of your antennas is on a 100 meter broadcast tower, you probably have VERY CAREFUL SITING (2). M assumes reciprocity in his predictions, i.e., he doesn't care whether SITE 1 is your transmitter or your receiver. It is up to you to keep them straight. And you must keep them straight as you will be shown a little later along. Your next screen will prompt you: Now give me your frequency in MHZ: You may enter integers or decimals, e.g., 150 or 150. or 149.28. .FO 6 Your next screen asks for your antenna heights: Give me the height of Terminal 1, in meters: 3 Give me the height of Terminal 2, in meters: 3.6 Here again, you may enter in meters or fractions thereof, as shown. Remember I said you should keep track of whether SITE 1 was your transmitter or your receiver ? (The words Terminal and SITE are used interchangeably.) If you have selected SITE 1 as your transmitter then you must use Terminal 1 as your transmitter as well. This brings you to the end of required data input. M will notify you of this with the message: You have completed all required input for prediction. Pause. Please press <return> to continue. Your next screen will be the reward for all your labor: PREDICTION FROM PROGRAM M VERSION 3.1 FREQUENCY = 100.00 MEGAGERTZ ANTENNA HEIGHTS: terminal 1 terminal 2 physical : 3.00 Mtrs 3.00 Mtrs effective: 3.00 Mtrs 3.00 Mtrs POLARIZED: VERTICAL VERTICAL CLIMATE = CONTINENTAL TEMPERATE Path Elevation = 0. Mtrs; DELTA-H = 90.00 Mtrs Ground: Dielec.const.= 15. conductivity = .00500 Siemens/Mtr N(0) = 301. N-Units and N(S) = 301. N-Units SITE CHOICE: SITE 1 WAS RANDOMLY SITED. SITE 2 WAS RANDOMLY SITED. BASIC TRANSMISSION LOSS IN DB RELATIVE TO FREE SPACE DIST FREE WITH CONFIDENCE KM SPACE 10. 20. 30. 50. 60. 70. 90. 100.0 112.4 172.1 174.1 175.5 177.9 178.6 179.5 181.0 Do you want another run? (Y/N or CODE) : .FO 7 And so ends a run through M, or so it might appear until you remember that there were two places where CODE was mentioned: When you first entered the data input sequence and second just now as you completed a run through M. Before we get into that, I would like to speak at the "output" you got from M. I am refer- ring to the row of numbers just above the final question about 8 lines above here. At the moment they are simply numbers until they are interpreted. In the introduction, I referenced Hufford,A.G., Longley,A.G., and Kissick,W.A., "A Guide to the Use of the ITS Irregular Terrain Model in the Area Prediction Mode", US Department of Commerce, NTIA Report 82-100. The output sample above was selected from that reference as a benchmark. That is, I wanted to be sure that what I came up with was at least similar to the results obtained by accepted experts in the field. The first number on the left "100.0" is simply your link distance in kilometers. The second number "112.4", is the free space loss (in dB) that your communication link would have IF you were in free space with your communication link. And the next seven numbers are the loss on your link with the confidences listed immediately above each number. I can see the disappointment on some of your faces. After promising that you would only need to be able to read, I bring you to this. But just think of what you have accomplished so far. You have gone entirely through an Irregular Terrain prediction for a communication link of your choice. You now know, with seven different percentages of certainty, what power loss you can AT LEAST expect for AT LEAST half the time on AT LEAST half of the links you could have chosen in the area where you want to communicate. And you did it all yourself. At this point you have a number of options. You can , of course, call on a Propagation Engineer (or a Communicator) for help. There are, however, things you can accomplish with M by yourself...like fine tuning your communication link. Go back and change one of the parameters that you can control, like: the height of your antennas, or the frequency, or your link distance. While you are doing that, watch what happens to the loss on your link. But entering that data was so cumbersome. Which brings us to those two CODE words mentioned before. There are several features of M which I wish to introduce you to: 1. A more rapid way to enter a set of data for a run through M, and 2. A more rapid way to change any one of the variables which you have entered. .FO 8 Go bring up M and get the screen: You are at the Threshold...Ready??? (Y/N) (or CODE): Now type "ROBERT", without the quotes but all in caps. You should see the following screen: You are at the first eschelon of SPTEST. Your options: OPTION 1 OPTION 2 OPTION 3 OPTION 4 KLIM 5 5 5 7 EPS 15. 15. 15. 25. SGM .005 .005 .005 .02 IPOL 1 1 1 0 KST(1) 1 1 0 0 KST(2) 0 0 0 0 FMHZ 400. 25. 100. 1200. HG(1) 10. 10. 3. 5. HG(2) 1. 1. 3 1000. DH 200. 200. 90. 30. DISTK 100. 100. 100. 100. and OPTION 5 for which you can input your own values. Choose one(1,2,3,4,5): Let me alert you to some dangers before we go further. Anytime life is made easier for you, look for the catch. You noticed, as you went through entry of data to M the first time, that you could do no wrong. Every time you tried to enter out-of-range data I nudged you back. The same will NOT always be true at the higher eschelons of M. Now, back to the screen just above. I have selected 4 optional sets of data which you can use. Let us follow through a selection of OPTION 3. Press "3" then <RET>. You should see: Your choice of routines (only one) is: 1 = QLRPS 5 = LRPROP 9 = AKNFE 13 = ERFC 2 = QLRA 6 = ADIFF 10 = FHT 17 = STANDARD HEADING 3 = AVAR 7 = ALOS 11 = H0F 4 = QERFI 8 = ASCAT 12 = AHD Select one of the above: .FO 9 These are the Subroutines and Functions used in M. You may get output from any of them. I have used the same names for them which are found in the references which were presented earlier, however, you will find some differences. For example, I have added the ERFC Function, which is the approximation to the error function for digital computers, from Hastings. Bear with me for just a little longer, however, and select "17" for the STANDARD HEADING. If you refer back to the output M provided a few pages ago, you will see that it is the same. Now, with that out of the way, look at the last line of M output. A "Y" will return you to the "safe" input sequence. However, if you enter "MILES" now, without the quotes, but all in capital letters, you will be asked: Do you want to use QERFI or ERFC ? (Y/N): Select "Q" then <RET> for the moment and you should get: ESCHELON THREE...DO NOT PLAY GAMES AT THIS LEVEL,PLEASE Your values are now set to: 1...KLIM = 5 7...FMHZ = 100. 2...EPS = 15.000 8...HG(1) = 3. 3...SGM = .005 9...HG(2) = 3. 4...IPOL = 1 10...DH = 90. 5...KST(1) = 0 11...DISTK = 100. 6...KST(2) = 0 12...EN0 = 301. Which one do you want to change?(1,2,3,...,11,12): Select one of the parameters for change, enter the number followed by <RET>, and you will be asked for the new value you wish to enter. The danger here is that at this eschelon, M is very trusting. You can enter out-of-range values and M will use that value(s) and give you legitimate looking output which may be totally erroneous. So travel around at this level with caution. Well, my friends, that is as far as time and money permit me to go with you at this juncture. I would very much enjoy giving explanations of, for example, Subroutine QLRPS output: .FO 10 ** OPT3 TEST VALUES FOR QLRPS ** FMHZ = 100.00 WN = 2.0964360 IPOL = 1 ZSYS = 0.00 GME = 0.11775E-6 DISTK = 100.000 EN0 = 301.00 EPS = 15.00 SGM = 0.005 ZQ = 15.00000 + i 0.89824 ZGND = 0.24916 - i 0.00692 100.0 112.4 172.1 174.1 175.5 177.9 178.6 179.5 181.0 Do you want another run? (Y/N or CODE): You know that: FMHZ is the frequency in MHZ, WN is the Wave Number, computed from WN = FMHZ / 47.7 (And you all know where 47.7 comes from, of course) IPOL is the polarity of the link antennas, ZSYS is ... But enough. I sincerely hope that you all have fun using M in analysing your communication systems, and if I ever get back to working on M, I shall complete explanations of all the optional outputs available in the program, enter tables of optional values to update the electrical properties of the ground used in M, incorporate more of the findings of recent researchers, and et cetera. Have fun, Miles .fo 11 ORDERING INFORMATION M registration provides you with a license to use M on a regular basis. You need register only one version of M. Individual registrations for M come in two forms. 1. Registration only of the copy you have in your possession. The registration fee covers the use of the program, ensures that you will receive notification of all updates, and entitles you to user support. This user support is restricted to M software and the current technological capabilities of M. More in-depth analyses of your communication systems can be negotiated separately. FEE $39.95 (introductory price) 2. This option covers exactly the same as option 1 above plus the provision of a diskette containing the latest version of M, and any and all current supporting documentation. FEE $50.00 (introductory price) IN ADDITION, TRIAL-USE DISKETTES ARE AVAILABLE FOR $10. THESE DISKETTES DO NOT INCLUDE REGISTRATION. THE FEE COVERS A DISKETTE, POSTAGE AND HANDLING. PLEASE USE THE ORDER FORM BELOW. The above prices cover single orders up to quantities of 100. Orders for 100 or more are discounted at 30%. For OCONUS (outside the continental U.S.) please send international money orders in U.S. dollars plus an additional $5 to cover postage. .fo 12 _______________________________________________________________ | | | *** ORDER FORM *** | |Remit to: Miles A. Merkel | | 2240 Golf Links Rd | | Sierra Vista | | Arizona 85635 | | | |Please send the following: | | | | ____ Trial-use diskettes @ $10 ea ............$ __________ | | (includes program and manual on diskette, | | but no registration or user support) | | | | ____ M Registration @ $39.95 ea ..............$ __________ | | (covers use of program, ensures notifi- | | cation of all updates and entitles user | | support.) | | | | ____ M Registration /w/ diskette @ $50.00 ....$ __________ | | (includes program and manual on diskette, | | use of program in accordance with | | licensing agreement, notification of all | | updates, and user support under the pro- | | visions described in ORDERING INFOR- | | MATION option 1.) | | | | Subtotal ...............................$ __________ | | | | Less 30% discount for 100 or more items.$<__________> | | | | 6% sales tax (Arizona residents only) ..$ __________ | | | | Total ..................................$ __________ | | | | Payment by: [ ] Check [ ] Cash [ ] Postal M.O. | | | | Name:__________________________________ | | | | Company:_______________________________ | | | | Address:_______________________________ | | | | _______________________ ________________ _________ | | City State ZIP | | | | Business Phone: (____)_______-_______________ | | | | Notes: * 30% discount for orders of 100 or more | | * OCONUS orders please send international | | money order in U.S. dollars and include | | an additional $5 to cover postage. | | * No C.O.D. orders please | |_______________________________________________________________| .fo 13