That is a microwave frequency for carrying their radio signals too and from the repeater sites up on the mountains. On many towers you will see dishes aimed horizontally in various directions. These are used to remote that repeater site with the main switch that controls the entire radio system. They use microwave on some towers because it is too cost prohibitive to run a data line, or use a VoIP line of some type. An oversimplication to be sure, but hope that splains the question!