In aviation’s early days, long-distance HF communications used wire antennas trailing behind the aircraft. Stored on a reel inside the fuselage, the 100- to 200-foot antenna was usually hand-cranked out and back in. Reeling in was important–to keep the antenna taut when trailing, its end carried a heavy lead weight, which became a lethal weapon if the antenna remained extended while landing.
Trailing antennas are still used in 16 Boeing E-6Bs (derivatives of the 707) operated by the DOD as airborne national command posts to cover national emergencies and other situations. Officially called TACAMO ships–a John Wayne-sounding acronym standing for “take command and move out”–E-6Bs can even communicate with submarines, using very powerful, very low-frequency transmissions and a trailing antenna.
Steer clear of E-6Bs, though. Rockwell Collins has just won a ground-support contract for the TACAMO antennas, which the company notes are 28,000 feet, or 5.3 miles, long.