Popularized by my friends at:
QRP Amateur Radio Club International
QST, June 2000 issue, Page 31
The Grid Locator and Field Hunting newsgroup
Enter the longitude and latitude of two points in the standard +- format. For example: Chicago is Latitude: 41.880833, Longitude: -87.62785. Optionally, you can enter the gridsquare (2 4 or 6 characters) and the calculator will automatically convert to Latitude and Longitude. Values for South and West are to be negative. Enter your power out in watts, and press the button!
If you want to see a map of your two points, press the Show Map button.
You can get coordinates for any site on earth through MapBlast! or coordinates of a callsign via BuckMaster. These, and other useful links are in the Tools section of the calculator. For ease of use with the calculator, I suggest you open tools with a RIGHT mouse-click, and "Open in New window", that way you can copy and paste back to the calculator window.
If you are really desperate to find a location, try: NIMA They have a database of tons of towns across the whole world.
I based my distance calculator on the above formula. While not exact, it should give you results that will be within a couple of miles.
For further discussion, refer to http://www.census.gov/cgi-bin/geo/gisfaq?Q5.1.
Note that this program will takes lat/lon input literally. That is 52 degrees, 20 minutes is 52.3334. 52.3333 will resolve a different gridsquare than 52.3334. (No biggie). To experment, try 52.3333lat by 5lon and 52.3334lat by 5lon. Note how they come up with J022mh and J022mi respectively.
For further information on this, check out:
Please direct comments to N9SSA@arrl.net.
Last update 3.Oct.02