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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
