Enter the latitude and longitude of your location and press the button to see broadcast television stations within the given range of your location. Use the magnetic declination field to correct for compass headings.
To find your latitude and longitude, use a site such as http://www.juggling.org/bin/un.cgi/map-find to zoom in on the area you desire. Some mapping sites also provide this information by address, though sometimes you need to view the map graphic's URL to find it. Longitude will be a negative number; if the site you obtain a US/Canada/Mexico longitude from provides a positive value, enter it here as a negative value. To find the magnetic declination at your location, you can use http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl.