K1RZ / W3SZ Database
Enter your 6-digit, 8-digit, or 10-digit grid (or your 4-digit grid if you don't know your 6, 8, or 10-digit grid)
and optionally the height of your antenna ASL (Above Sea Level) in meters.
If you don't specify an altitude, then the SRTM altitude for the center of your grid square will be used.