KREF is the callsign issued to me by the U.S.Federal Communications Commission as part of my license to set up and operate an amateur radio station. It permits me to operate my station anywhere in the United States or on ships and aircraft registed in the U.S. when they are in or over international waters (subject to approval by the person in command of the vessel or aircraft). I can operate on any frequency or mode authorized for amateur use in the U.S. or Canada. I can also operate in a large number of other countries who have subscribed to an arrangement designated at CEPA.
The last hf station I operated was very modest, using the Icom 737 transceiver.
My antenna was not very elaborate either.