In June 2009, Mississippi Public Broadcasting (MPB) culminated a multi-year effort and inaugurated two-channel HD Radio transmission to all eight of its Class C FM analog stations. A digital signal now covers the entire state with better penetration and reaches portions of Alabama and Louisiana. In addition to the analog signal, listeners now have the choice of a separate HD Radio Think Radio channel, primarily a talk format, or an HD Radio channel that is mostly classical music. The project was funded through a grant from the Digital Distribution Fund of the Corporation for Public Broadcasting and makes MPB the only statewide HD Radio broadcaster in the state.
Besides the objectives of offering HD Radio quality with improved reception throughout the state, especially in areas where reception was marginal, MPB's decision to go digital was in response to listener complaints and preferences. Classical music lovers, an important group of MPB listeners and avid supporters, resented having their music interrupted with news and talk. The talk shows constantly vied for more air time to broadcast information. Two HD Radio channels solved the programming conflict while delivering more focused content to both audiences.
MPB transitioned to DTV in 2002, but it wasn't until 2008 that the road to HD Radio began with the installation of Continental 816HD FM transmitters at four of its eight FM stations. A major upgrade of the master control television studio to HDTV occurred in 2007 and 2008, which included equipment upgrades for the radio control room and studios. The installation of four more Continental FM transmitters, eight Jampro JHPC-HD high-power antenna systems along with new transmission lines began in January 2009 and was completed on June 23, 2009. Startup of the final installation was delayed somewhat because MBP's WMAB-FM transmitter located in Ackerman, MS, and licensed to Mississippi State University had a minor interference issue with WABG TV 6, an ABC affiliate located in Greenwood, MS. The FCC required WMAB to remain on its analog antenna until after the WABG converted to digital in mid-April 2009.
MPB's Technical Services Department worked closely with Kessler & Gehman Associates, their broadcast engineering consultant based in Gainesville, FL, to design and specify the HD system, which was released for public bids.
Jampro was selected as the best cost-to-specification for the eight new antennas. Because most stations were non-directional, circularized pattern optimization was critical to MPB's decision. In order to select the best pattern for each station, to offer maximum coverage and greatest penetration, MPB personnel traveled to California and worked with Jampro engineers on its 7,000' full-field test range. Approximately 10 different pattern tests for each station were run in several scenarios to achieve the required optimizations.
-- continued on page 2