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stlsit.doc
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INI File
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1990-10-14
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87 lines
[STLSITE.DOC]
This is the documentation for STLSITE.BAS.
STLSITE.BAS is an IBM Compatible Pc program which calculates
a set of statistics, like an FM channel study, on an STL database
for a given locality. The demonstration STL database is file
WBSCR.STL and the output file for a site study using it is WBSCR.OUT.
The program is a companion to my article:
Planning an STL System in the October 1988 issue of
BROADCAST ENGINEERING. See it for more information on the use
and basis for the program.
STLSITE.BAS is a calculator style program that requires
a working knowledge Ms-dos at the system level. The use of EDLIN to create and
maintain the STL database file (It calculates line by line using the data
in the STL file.) and the manipulation of files at the Dos level. For each
frequency and STL system in the database, it calculates the transmit
azimuth (bearing) and the distance to the receive site for each system,
the bearing and distance to the proposed STL receive site, and the
line-of-sight clear path loss to it.
Due to the many variables that can influence the usefulness of the STL
frequencies, it performs no selection. It just calculates a set of STL
database statistics that can be used for finding a frequency or verifying a
recommended one. Due to the many radio marketplace variables, that's best done
using a mix of the intuitive and the obvious. See the article for information
on things that affect the frequency selection and use criteria.
HOW TO USE AND HOW IT WORKS:
To use you need an database file created with EDLIN. Refer to the
demonstration database file WBSCR.STL. The first line of the file identifies
the locality. Following this, each line represents one file record---one
for each frequency. Each record, from right to left: Frequency, Station,
STL/TSL, Polarization, then transmit latitude and longitude, followed by
receive latitude and longitude. The program uses coordinates to calculate
the azimuths (bearings) and the distances, and it expects to find them
at fixed locations in each record:
Transmit latitude beginning at position 25 (program line 315);
transmit longitude beginning at 32 (line 320);
receive latitude beginning at position 40 (line 321);
and receive longitude at 47 (line 330).
The program error tests for 0 only. It assumes data at those locations in each
record are valid geographical coordinates and the accuracy of the
statistics depend on that.
To use the program, enter the database file name. If it's not found
the program errors out to Basic. If found then the program prompts for the
coordinates of the STL site. Enter on one line in the format: DDMMSS/DDMMSS.
The / delimits the latitude from the longitude for the program. An error, 0
or no /, restarts the program form the top. In a minute or so, providing
there were no errors in the database file the STLSITE recalculates the
database and writes it to a file using the same name as the database but with
an extension of .OUT. The DOS prompt appears when it's done. Use the TYPE
command to see, or print the STL Channel study for the STL site.
ABOUT THE PROGRAM:
Lines 100-150 prompt for the STL database file name and the coordinates
of the proposed STL site. Lines 200-250 opens both files. Lines 300-360 read
the record, convert the coordinates to decimal degrees and compute the bearing
and distance for the system. Lines 400-445 computes the same using the
proposed STL site for the receive location. Line 450 is the bottom of
this program loop which terminates when it detects an EOF (end of file). Lines
5000-7050 is the distance and bearing subroutine. It uses the FCC's 73.208
algorithm. Lines 8000-8030 is the subroutine which converts the
coordinates to decimal degrees for calculations. And, lines 8050 is the
program's file error trap. On an error in the file's record, it displays the
record, and then returns to DOS. Then, use EDLIN to fix the file and try
again.
THERE'S HELP:
I will provide a limited amount of support, by mail, for anyone having
problems or comments on the program. You can reach me at my home address:
Ronald F. Balonis
118 Rice Street
Trucksville, PA 18708