The waveguide passes through a rotary joint at the top center of the azimuth arm. It then proceed down to the bottom of the arm to the continuously adjustable two-way power divider. One output of the divider supplies power to the carriage house while the other output supplies power to the Gregorian dome. This dual-beam operation is equivalent to two radars pointing in different directions. Connections from the power divider to the carriage house and the dome require the equivalent of telescoping waveguides to accommodate motion along the elevation track. This is accomplished by using a slotted waveguide fixed to the bottom of the azimuth arm. The slot (which has negligible radiation loss) points downward. A pickup probe extends from the carriage house up into the slot. The probe is actually a special waveguide elbow with wheels. This "collector" travels along inside the slotted waveguide. It has a half-height output port that passes through the approximately 8" wide slot. A 5-probe tuner at the junction of the WR2100 and the slotted waveguide eliminates reflections that would be produced at this junction. Power from the collector enters the carriage house though a length of corrugated waveguide and is connected to a turnstile junction. The lengths of the side arm shorts on the turnstile are adjusted so that a) no power is transferred from the transmitter port to the opposite port (the receiver port) and b) that the power leaving the antenna port has circular polarization. When the transmitted signal is reflected by a radar target (the ionosphere, the moon), etc.) the echo returns with the opposite circular polarization. The turnstile routes this echo power to the receiver port. This turnstile junction/circular polarization setup is therefore "self diplexing" - no additional hardware is needed to switch the antenna back and forth between the transmitter and the receiver.