The AM Broadcast mapping program
This program for the hobbyist shows a polar-projection map of all the medium-wave broadcast stations in Region 2 (Western
hemisphere) that are shown in the FCC database. This includes North America, Central America, South America and the
Caribbean. The patterns of all stations on a user-specified frequency are shown. The map is centered on a user-specified
home location with a user-specified map size.
Please note that no updates are planned for either this program or the associated database files.
- All stations on an entered frequency are shown. The U.S. stations are shown if they are licensed;
outside the U.S. all stations are considered licensed and so are shown.
- Click on "Frequency" to select the channel for display. An option at that point is to clear the map
and show only the stations on that channel, or to add another channel to the map. A third option on that page is a
single button-press to add the adjacent channel stations to the display.
- Click on "Hours" to show only daytime signals, or only nighttime signals or both. Unlimited and
critical-hours operations are always shown.
- Click on "All" to show all stations on all frequencies. This is especially useful while traveling, to
find stations while zoomed in to your immediate area.
- While you are on that screen, choose a frequency and add the station's pattern plot to the map. Do
this for each of the indicated frequencies and you can see all the stations in that area, their calls, frequencies and
- Click on "Home" to set the map so that you are at the middle of the screen. You can simply select
from a list of cities, or select from a list of callsigns or enter the latitude and longitude.
- Click on "Hets" to see the stations in other regions that may be causing a beatnote to the target
frequency. Both the frequency of the beat and the interfering carrier frequency are shown.
- Click on "GetData" and you can retrieve the data for an entered call; this includes city, state,
country, latitude, longitude, power and number of towers. Then click on one of the lines of data in the resulting
listbox and see the pattern for that operation (day, night, etc.) along with a map of the antenna array. This
information can be sent to the printer.
- While you are on that GetData screen, click on "Maps" to see a small map with the station in context.
This plotted map is rescalable.
- While you are on that Maps screen, click on the "GoogleMap" button to call up Google's mapping
routine to see a map of the site.
- Another option on the GetData screen is the "Towers" button. Click on that to see tabulated data
about the towers in the array.
- Click "Zoom-in" or "Zoom-out" to change the size of the map. Pattern sizes track the maps size.
- Click "Larger" or "Smaller" to change the stations' pattern sizes relative to the map of the
- Click "Options" to change the colors of the various pattern types - Day, Night, Unlimited, Critical
and Adjacents. A button is available to restore default colors. Also available on the Options screen is the Google Maps
language selection: French, English or Spanish.
- Click on "Distance" and you can find the bearing and distance from the home location to an arbitrary
latitude and longitude. Output is in miles or kilometers.
- Click on "Compass" to overlay a compass rose on the plot to show the direction of a station from the
- The outputs to the printer are from separate routines which closely duplicate the outputs as seen on
the screen, but in very high resolution, without rastorization or pixelation. To send a plot to the default printer
just press the "Print" button.
- At program exit the setup data is saved for an easy restart.
- The program has an aspect-correction capability to accommodate monitors with varying degrees of
shape, vertical to horizontal. The correction factor is saved for use during the next session.
- The database currently covers all Region 2 stations in the FCC database that are licensed as of 1
December 2009. Excluded are "New", "STA" and "XENVA2" stations.
- The program does an enormous amount of computation to replot a new screen and so for a reasonable
reaction time to a request for a change (new frequency, new home location, etc.) a fast computer is needed. The
reaction time is about one second for such a complete screen replot on a 2 GHz machine (and so is about ten seconds for
a 200 MHz machine, which is the slowest recommended). If a slower machine is used the program may be installed and used
but a warning message will be displayed and program operation may prove annoyingly slow.
- Please note that no updates are planned for either this program or the associated database