Abstract: Antennas for transmitting and receiving circularly polarized UHF SATCOM radio signals include a mast which has four circumferentially spaced apart element mounts that protrude radially from the mast, each having a mechanical coupling mechanism holding an electrically conductive tubular antenna element disposed radially from the mast for use and parallel to the mast to minimize the envelope size of the antenna when not in use. Replaceable elements in one version of the antenna have a threaded stud threadably receivable in a threaded socket on the element mount. Each element of a foldable version of the antenna has a tapered support peg which is insertably receivable in a tapered socket in a boss on the element mount and releasably held therewithin by a tensioning spring within the element. Optionally, a fifth conductive element is disposed longitudinally within the mast to transmit and receive linearly polarized radio signals.