Buoy supported underwater radio antenna

摘要

A buoy supported antenna comprises an elongate section 160 attached to an underwater object 141 at a first end and during deployment is suspended by a buoy 154 at a second end. The said elongate section 160 comprises at least a substantially vertically oriented portion with a flexible electrically conductive wire core 151, with an insulated plastic jacket outer surface, which radiates electromagnetic signals through water. A coaxial cable and balun or balanced spaced apart pair of insulated flexible wires may be used as a signal feed line 152 connected to a feed network 153 somewhere between the first and second ends of the elongate section 160. The end or centre fed dipole antenna 150 may include an electrically conductive screen and/or counterpoise. The length of the elongate section 160 may be an integer multiple of one quarter of a wavelength at a central frequency of operation within a range of 10 Hz to 10 MHz. The elongate section 160 may be vertically oriented within a range of plus or minus 20 degrees. The said object may be a remote operated vehicle 141, an underwater hydrocarbon extraction or drilling facility 142 or a fixed seabed installation. A remotely controlled motorised reel mechanism may be used to deploy and retract the antenna 150.