From Randy K7AGE
I’ll show you how to use WSPR software to check to see if my antenna is working. WSPR sends your call sign, power level and grid square during a nearly two minute transmission. Receiving stations decode your transmission and post the results to an online database. You can use a website to view a map of of the station that you have heard and stations that have heard you.
WSPR is written by Joe Taylor, K1JT
WSPR, software and users manual
WSPR Net, map display
Grid Square Map
Setallar WSPR, receiver kit