SALT LAKE CITY Independence Broadcast Services provides comprehensive AM and FM broadcast engineering and construction services, from signal enhancements and spectrum analysis to turnkey construction and FCC application processing.
One of the company’s specialties is the design and implementation of synchronous booster systems for transmitter networks. The company was recently hired by KYLZ(FM) to improve its coverage throughout the Salt Lake City market.
Humpy Peak
KYLZ signed on the air in April. The station is the seventh “Humpy Peak” station to sign on the air, having been relocated from its previous community of license, outside of the market.
An installed Harris Intraplex SynchroCast quietly coordinates transmission. Humpy Peak is located on the western end of the Uinta Mountains, a sub-range of the Rocky Mountains. The Salt Lake City/Ogden/Provo market lies to the west of Humpy Peak and on the other side of another range of mountains — the Wasatch Mountains, which rise nearly 12,000 feet high. The Wasatch Range is in the direct transmission path from Humpy Peak to the Salt Lake valley, creating various transmission challenges throughout the market.
To ensure full market coverage, KYLZ hired Independence Broadcast Services to design, build and integrate a booster system that would cover the entire Interstate 15 corridor from Ogden through Salt Lake City and south to Provo.
The company selected a Harris Intraplex SynchroCast T1 digital multiplexer system to connect the main KYLZ transmitter with four synchronous co-channel boosters. A fifth booster will come online later this year, providing even more fill-in coverage.
The primary role of the Intraplex SynchroCast system is to provide synchronization for the co-channel boosters. The fact that KYLZ’s is the seventh installed system in this market demonstrates the success that area radio stations have had using SynchroCast for signal transmission across very challenging terrain.
SynchroCast overcomes the mountain “wall” created by the Wasatch Range by providing fill-in service in the valley. Along with proper antenna and RF design, the synchronization technologies enable seamless coverage from north to south. Without SynchroCast, co-channel interference created between the main antenna site and the various booster sites would render the signal unusable in many areas. Overlaps are significantly reduced with SynchroCast and the handoff from one transmitter to another while driving through the overlap areas is nearly impossible to discern.
GPS digital timing is the critical element of this synchronization. The unit’s internal GPS system provides KYLZ with a common time reference so the station can delay audio at each booster site as required. This means that when a specific frame of audio is transmitted, it arrives at the overlap areas at the precise moments required to maintain a synchronized signal across the booster network.
GPS provides this precision down to the microsecond. The ability to achieve that precise of a time measurement is critical to maintaining a clean broadcast throughout the market.
Furthermore, SynchroCast incorporates dynamic, hitless delay control, so that if the actual T1 circuit delay to any site changes, the system automatically will adjust to compensate without disturbing the audio broadcast in any way.
Transport system
The Intraplex SynchroCast essentially is a digital multiplexer that can transport audio, data, voice and LAN capability between multiple sites. The LAN capability is significant to this operation, as SynchroCast enables high-speed Internet between all five sites and the KYLZ studio.
More important, the LAN connectivity allows KYLZ to use IP-compatible telemetry systems for confidence monitoring and signal reporting at every site. This allows the station to utilize a more reliable, less expensive way to gather readings and respond to operational issues instead of using land lines and cell phones to dial into sites. Confidence monitoring is achieved through automatic feeding of audio received on tuners at the transmitter and booster sites back to the studio, where operators can listen to each site as it transmits over the air. This would be cost-prohibitive using legacy equipment with leased land lines.
Harris has also provided Intraplex CrossConnect servers with this system. CrossConnect servers enable backup paths to distribute information in the event that a specific link is taken down for maintenance or otherwise temporarily offline. The automatic switchover features enable the booster system to redirect itself seamlessly to another booster site, and automatically retime the signal for proper synchronization across the network.
The CrossConnect servers are perhaps the most powerful components of the entire system, providing redundancy capabilities that are critical to the success of the transmission and booster network.
Intraplex SynchroCast was the first system on the market to enable synchronization across multiple transmission points, and the product has been updated and enhanced in a manner that continually meets the needs of Independence Broadcast Systems and our radio broadcast clients including its newest IP-based NetXpress SynchroCast system.
Kevin Terry and Bert Goldman are vice presidents at Independence Broadcast Services.
For information, contact Harris Broadcast Communications at (513) 459-3400 or visitwww.harris.com.
