Tha insulated backstay is used as HF-antenna. The backstay is connected witha tinned copper wire to the MFJ-926B antenna tuner which is located directly under the backstay in the lazarette. The wire antenna was connected to the wire post. The ground was attached to the other wire post on the tuner.
12V power supply of the antenna tuner
The 12V supply to the antenna tuner is fed into the coaxial cable through a bias tee, so no extra cable was needed. DC and HF power is then separated inside the tuner. The tuner uses 0,75 A maximally an can be switched off when the transceiver is just used for reception.
The TS480 SAT uses the same ground for 12V power supply and for the coaxial antenna cable. The connection to the ship ground would therefore loos the advantage of two separate ground systems. So the ground connection of the HF radio was realised using a plug. The ground connection is disconnected when the HF radio is not in use.