Although the FLO TV signal is digital, it’s transmitted by sending microwaves. Switching between the two microwave transmitters means physically switching the pipe that the microwaves are sent down, which is done by the small protruding motors on this microwave array. The square pipes are wave guides carrying signals from the MediaFLO transmitters and they enter the array at the top, pass through the switches, and lead out to the satellite uplink dish. For redundancy, both transmitters are always on, even though only one of them is transmitting at any time, so the standby transmitter is still producing a signal–although at a lower power and without the actual TV channels in it. That means this array has to dissipate the standby signal as heat, which it does using the "dummy loads" (which look and act like heat sinks) at either side of the array.