The summit of the Bradshaw Mountains rises more than 8,000 feet above ground level in central Arizona's Sonoran desert. Approximately 66 miles north of the Phoenix city limits, the transmission facility for two Sierra H Broadcasting FM stations is situated near the highest mountain peaks, among the Ponderosa Pines and short-horned lizards.

The location is certainly prime real estate for high-power FM transmission, but not without its challenges when modifying an outdated RF facility.

Klein White Broadcast Engineering is a full-service design and engineering firm that primarily serves the Phoenix area. Sierra H Broadcasting essentially hired us to install a transmitter for KNRJ-FM, the second of two stations to consolidate into the mountaintop facility.

The facility was already home to KAJM-FM, having moved in four years prior. At the time of the KNRJ move-in, KAJM was operating a Nautel NV30 with half of a Harris Platinum Z-16 transmitter in backup mode. The Platinum Z had once operated as the main 16kW transmitter, but took a series of lightning strikes -- more than 14 in one night -- rendering it nearly useless. It was rebuilt as a double-cabinet 10kW transmitter (single-phase) and put into backup.

Meanwhile, the previous engineering team installed the Nautel unit -- a robust and reliable transmitter, but too enormous for this project on two levels. First, a 30kW transmitter for a 15kW TPO was an unusual choice (IBOC had been considered, but then decided against); second, the large footprint took far too much room in a space-challenged, 22x22-square-foot building.

The big question: How do we move a second transmission system, complete with main and backup transmitters, into a building with almost no additional space?

The answer: A near complete redesign.

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