How to calculate your Grid when operating Away From Home
GA - Bob - K4VBM
This is what I use to calculate my grid based on my current GPS coordinates provided by a USB GPS plugged into my laptop:
"New Improved" WinGrid Ver5.2 (wingrid.exe) This program calculates grid squares from latitudes and longitudes, the reverse, and calculates distances and headings from two sets of lat/long or grid squares. The program saves your home QTH information. Click on "DISTANCE" to convert from miles to kilometers. Version 5.2 calculates extended (8 character) grid squares. The software was extensively revised and cleaned up for this new version. Version 4.0 corrects for a minor error in heading calculation for opposite sides of the earth. Version 3.9 displays both forward and reverse headings. Version 3.8 corrects a minor error in the minutes value for the center of a grid square. Version 3.7 uses a much more accurate distance algorithm, accounting for the earth's polar flattening and equatorial bulge. Starting with Ver3.6 it is possible to switch between "DD MM SS" and "DD.ddddd" for latitude and longitude. L-click twice on the home or destination boxes to switch between "DD MM SS" and "DD.dddd" formats for each box. L-click twice on the main frame to change both home and destination windows at the same time. This version also saves the format and "miles" or "kilometers" for the range. On starting the program or "Recall Home" these will be reset. Starting with Ver3.5, the program begins with the cursor on the Destination Grid box. Enter a value and hit "ENTER". Distance and heading will be instantly calculated. The Ver3.4 upgrade corrects a minor problem with grid squares near 30 second "boundary lines" in Ver3.3.