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WMHT Relies on Harris Intraplex HD Link STL

User Report: Public radio station implements digital buildout with Harris package

TROY, N.Y. — As a public radio broadcaster serving upstate New York through western New England, WMHT(FM) 89.1 provides classical music programming, including nationally renowned and local concert presentations. Sister station WEXT(FM) 97.7 offers an eclectic adult alternative music mix that crosses genre boundaries.

We consider it paramount to offer the best listening experience possible since our service is largely supported by music aficionados. Classical music especially is challenging to broadcast, as listeners want to hear quiet passages, like a solo violin, without distractions from circuit noise or digital artifacts.

Key features

When our facility transitioned from analog to HD Radio in June 2010, we based our critical studio-to-transmitter (STL) link on the Harris Intraplex HD Link digital 950 MHz STL gateway. The Intraplex HD Link is designed to relay IP-encapsulated, uncompressed audio programs.

HD Link was part of a comprehensive, end-to-end Harris HD Radio transmission solution that included the company’s Z16-HD transmitter and FlexStar HD Radio system (HDI-100 importer, HDE-200 exporter and HDx digital FM/HD exciter).

We purchased a second Intraplex HD Link to serve as a hot standby for redundancy. Both systems are configured to run in parallel, although switchover is manual.

HD Link carries a multiplex of signals including WMHT(HD), WMHT(FM) and WEXT(HD), as well as a stereo pair and analog signal for RISE, our reading service for the blind and print-disabled.

The system is capable of carrying ancillary IP data with advanced forward error correction. Although we do not have this feature enabled at present, its availability was key to our decision.

The Intraplex HD Link digital 950 MHz STL carries a signal multiplex from our studio facility in Troy, N.Y., to our transmitter site 16.25 miles away in the Helderberg Mountains. Our digital microwave system gives us a “clean shot” from the studio to the transmitter building. A Harris feature called low-density parity check (LDPC) coding provides advanced error correction for an efficient, high-performance STL signal transport.

The signal is fed directly to the exciter at the transmitter site, feeding our 11 kW Z16-HD transmitter. The Z16-HD blankets our extensive coverage area, including Schenectady, Albany, Troy, Amsterdam and Kingston, N.Y., as well as western Massachusetts and southern Vermont. Another station in our group, WRHV(FM), picks up the WMHT signal off-air for broadcast to the Poughkeepsie, N.Y., area.

We’re a public radio broadcaster, so cost and reliability were crucial factors in our decision to purchase the Harris package. The new Z16-HD transmitter replaced two older Harris analog transmitters, a 10H installed in 1972 and a 10K installed in 1983 as a backup. Both served us well over the years.

We particularly like the high-caliber technical and customer support and one-stop-shopping convenience Harris provides. The Harris HD Radio and STL solution is an integrated, robust, end-to-end system that saved us from cherry-picking and integrating components from various manufacturers. A Harris technical representative handled the installation and systems integration, and provided on-site training for our engineering team including Chief Operator Dirk van Rijsewijk, Engineer Dave French and myself.

Being able to multiplex and monitor the signals from the studio is a time-saver and a convenience. System monitoring is accomplished using the front-panel interface and LCD display of the STL transmitter unit situated in one of our control room racks, via a touch-screen PC, or using a remote Web browser user interface and SNMP remote control for off-site monitoring. The system can be configured to send alarms or alerts to designated personnel.

The greatest benefit is the “set it and forget it” operation. The HDLink is stable, with a power meter that just remains in the same spot. We’ve had no signal disruptions since our HD Radio infrastructure went on the air. Reliability is of utmost concern since WMHT, WEXT, and RISE must rely on the Intraplex HD Link 24/7. Because it transports uncompressed, CD-quality audio to our transmitter site dependably and is easy to maintain, Intraplex HD Link has proven to be an excellent investment for our facility.

David Nicosia is manager of engineering for WMHT Educational Telecommunications.

For information, contact Brian Clifford at Harris in Ohio at (800) 231-9673 or visit