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2009 in Review: 2 GHz BAS Conversion Nearly Complete

Finally, I can't wrap up coverage of 2009 without mentioning the near completion of the long and tedious process for squeezing the 2 GHz (1990 to 2110 MHz) broadcast auxiliary services (BAS) to the 2025-2110 MHz spectrum block, while retaining the same number of channels via reduced bandwidth and conversion to digital modulation. This task required a one-time ramping up of microwave equipment production, straining the limited number of tower crews qualified to do microwave installations. The transition also often involved the installation of very large steerable antennas mounted at or near the top of tall towers or on towers located on mountain peaks with limited accessibility.

The good news is the relocation is nearly complete except in a few markets with specific problems. Unlike the DTV transition, the changes this conversion brings aren’t immediately obvious to viewers, other than as a different set of artifacts from weak signals. As broadcasters upgrade their new digital equipment to support live HD newsgathering in 2010, the impact should become more obvious.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.