Nautel Asymmetrical Sidebands Boost WAMU HD Radio Coverage

September 30, 2010

Washington, DC - Sep 29, 2010 - Public radio station WAMU is the first station to expand its HD Radio coverage by implementing asymmetrical sidebands and elevated carriers as part of a trial using the Nautel HD PowerBoost. The technology allows WAMU to boost one sideband to the full -10dB HD Radio signal while keeping the other sideband at a more conservative -14dB injection level thus maximizing digital coverage while avoiding interference with an adjacent upper or lower channel.

WAMU, licensed to American University in Washington, D.C., is a progressive user of HD Radio technology and was one of the first HD Radio multicast stations in the country. The station recently won a Multicast of the Year award for its bluegrass format on WAMU's Bluegrass Country. To further extend its HD Radio coverage, WAMU installed a Nautel NV40 transmitter last year with plans to increase power to -10dBc, but to avoid adjacent-station interference, WAMU found that it would be limited to just -14dBc power on the lower sideband. Utilizing Nautel HD PowerBoost, WAMU has been able to increase its upper sideband to -10dBc while retaining the previous level of -14dBc on the lower sideband. The result has been greatly enhanced digital coverage without adjacent-channel interference.

The asymmetrical capability, which is subject to FCC approval, will be available as part of Nautel's HD PowerBoost. The technology offers several features including an enhanced peak reduction algorithm which permits up to 30 percent more power while at the same time improving transmitter efficiency. It also enables the transmitter to offer asymmetrical sideband ratios as needed, based upon individual station requirements. Nautel is the first transmitter manufacturer to offer this set of HD Radio tools. This technology can also help HD Radio stations mitigate interference complaints.

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