A method for constructing a transmission line unit such that load coils can be selectively connected to a transmission line includes providing a transmission line section having a transmission line and a plurality of load coils electrically connected thereto, and connecting a switch terminal having a plurality of switches to the transmission line section. Each of the switches in the terminal is electrically connected to a respective load coil and is configured to selectively connect the respective load coil to the transmission line. Each switch may have a first switch position that connects the respective load coil in series with the transmission line, and a second switch position that disconnects the respective load coil from the transmission line. The load coils may be provided in an enclosure that is separate from the transmission line and the switch terminal. Related systems and terminals are also discussed.