This picture looking north shows that the fiberglass covers of the Sunol route horns are slightly bulging outward. This is an indicator that the waveguide dehydrator (air dryer) is actively providing a positive airflow into the waveguide/antenna. This could mean that the antennas are in use. Perhaps AT&T retrofitted a digital microwave system (DR-6?) to service the DMS-100/200 digital switching systems in Sidney and Scottsbluff. I suspect that these sites then feed out of the fiber cable routing into/through Chappell.