It goes by several names, each of which actually address a different element in the system. Airborne transmitters run 1000 watts and the signals can be heard on the ground for over 150 miles when at altitiude.
Most platforms can act as relays for the signals as well.
Air to Air range is in excess of 350 miles. Most of this system is defunct, but support for this function remains. In the 1980's GEP's were often referred to by their town's real names by operators on the system. Today the trend is toward rotating tactical callsigns for the GEP's, though one sometimes still hears operators mention specific GEP sites. See below for web links to GEP site listings, pictures, tours, preservation societies, etc.