A manual for
       UAREA,  "User's Area model"

   This is a main program designed to illustrate one way to use the ITM
in the area prediction mode.  The program is interactive; it asks for input
in a series of "virtual cards" and then writes the output to a user-named
file.

  *Input*
   Input is designed to appear like a sequence of prepunched cards which
the user is to correct.  Fields are always 10 columns wide and entries are
either single characters or real numbers.  In operation, there first appears
a line or two defining the card, then a header providing mnemonics for the
successive fields, and then the card itself with vertical lines separating
the fields and the current values "punched" in.  Finally the program stops
and awaits input with the cursor on the next line.  If all current values
are satisfactory, one can simply strike the "enter" key.  If some are to be
"corrected," one should space over to the proper field and type the correct
value.  Note that one is simply responding to a Fortran input command.  To
move the cursor one can use either the space bar or the backspace key.  The
cursor movement keys will not work.
   The four cards of this program are described below.

  *Card 1: System parameters.  These consist of H1, H2, antenna heights of
the two terminals, measured in meters; F the radio frequency in MHz; Pol,
the polarization, either horizontal or vertical; and the siting criteria
for the two terminals.  Horizontal polarization may be indicated by either
of the characters 'H' or '0', while vertical polarization is indicated by
either 'V' or '1'.  A siting criterion is one of Random ('R' or '0'),
Careful ('C' or '1'), or Very Careful ('V' or '2').

  *Card 2: Environmental parameters.  These are DH, the terrain irreg-
ularity parameter "delta h", in meters; Ns, the surface refractivity, in
N-units (parts per million); Clim, the radio climate; eps, the dielectric
constant of the ground; and sgm, the conductivity of the ground, measured
in S/m.  The climate is indicated by a single character and may be
Continental Temperate ('C'), Maritime Temperate OverLand ('M'), or Maritime
Temperate OverSea ('S').  It can also be indicated by the "climate code,"
which is a single digit 1,...,7 corresponding to:
          Clim = 1, equatorial
                 2, continental subtropical
                 3, maritime subtropical
                 4, desert
                 5, continental temperate
                 6, maritime temperate, overland
                 7, maritime temperate, oversea

  *Card 3: Statistical parameters.  These are Var, the mode of variability;
QT, the required percentage of time; QL, the required percentage of
locations; and the QC1, QC2, QC3, QC4, as many as four confidence levels,
given as percentages.  The mode of variability is indicated by a character,
and may be Single Message ('S' or '0'), Accidental ('A' or '1'), Mobile ('M'
or '2'), or Broadcast ('B' or '3').  Depending upon this mode, the variables
QT and QL may or may not be appropriate.  If not, they are simply ignored.
The output is a table of quantiles whose rows represent a sequence of
distances, and whose columns represent the different confidence levels.  The
number of columns is therefore determined by the number of confidence levels
and this is determined by the list of QC's.  The first blank field (or 0 or
negative value) marks an end to this list.

  *Card 4: Tabulation parameters.  These provide the distances that will be
used as the first independent variable, thus defining the rows of the output
table.  There may be as many as 5 such parameters, d0, d1, ds1, d2, ds2,
all measured in kilometers.  These define the output through one of three
intended formats: (i) d0 alone with the remaining variables omitted--
only the single distance d0; (ii) d0, d1, ds1 alone--distances from d0 to
d1 in steps of ds1; and (iii) all five variables--after stepping through
to d1 as above, distances continue on to d2 in steps of ds2.  If some of
the variables such as the step sizes are undefined, the program uses its
own algorithms to define them.  For example, if d0 is not positive it is
replaced by ds1.

  *Further Input*
   Following the four "cards" are three questions which should be answered
on the same line and concluded with the 'enter' key.  The questions:
      >needs editing(N)?  To make emendments to the input data, one answers
          'Yes' ('Y') and the program presents the four input cards again.
      >A title?  If a top-line title is desired it should be entered here.
          Up to 69 characters may be introduced.
      >and the output file: ITM.DAT?  Here one may name the file (with its
          path) to which the output will be written.  If a proposed file
          already exists, the user will be asked whether the older file
          should be overwritten.  On the other hand, if a second run is
          made without exiting the program, and if then the file name is
          unchanged, the second table will be merely appended to the first.
   The program then does the required calculations, writes the output to
the named output file, and then asks the one last question:
      >exit (N)?  If the response is not 'Yes' ('Y') the program returns
          to its beginning and expects to continue with another run.
   Incidentally, there is another way to make a fairly graceful exit.  If
the first field of a "card" is numeric, and if it is filled with an
illegal value (e.g., any letter) then the program will offer a chance to
exit.