External HF/VHF Antenna Switching Unit

This simple unit is fitted inside a small metal box and automatically selects the correct aerial for HF or 4/6 Metres. The unit houses two SO239 sockets for the HF and VHF aerials, a short lead with a PL259 plug which connects to the transceivers aerial socket, a 2.5mm standard coaxial dc socket for the 13.8 vdc supply and finally a short lead connected to Pin 7 of a 13 Pin plug which interfaces to the rig's accessory socket which now supplies the band changeover voltage.