High Quality Content by WIKIPEDIA articles! The High Frequency Global Communications System (HF-GCS) is a network of single sideband shortwave transmitters of the United States Air Force which is used to communicate with aircraft in flight, ground stations and some United States Navy surface assets. All worldwide receiving and transmitting sites in the HF-GCS system are remotely controlled from Andrews AFB. Before 1 October 2002 it was known as the Global High Frequency System (GHFS).