Nautel Asymmetrical Sidebands Boost WAMU HD Radio™ Coverage

WAMU becomes the first station on-air with Nautel’s award winning HD PowerBoost™ technology and asymmetrical sidebands. Using HD PowerBoost, WAMU has independently set the injection level of the upper and lower digital sidebands to maximize coverage while protecting adjacent stations.

September 29, 2010

NAB Radio Show 2010, Booth 6 — Nautel Limited announces that 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 Nautel’s HD PowerBoost. Nautel’s award winning technology allows WAMU to boost one sideband to the full -10 dB HD Radio signal while keeping the other sideband at a more conservative -14 dB 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 in order to avoid adjacent station interference, WAMU found that it would be limited to just -14dBc power on the lower sideband. Utilizing Nautel’s HD PowerBoost, WAMU has been able to increase its upper sideband to a full -10 dBc while retaining the previous level of -14dBc on the lower sideband. The result has been greatly enhanced digital coverage without adjacent channel interference.

“I’m pleased to report that the increase in lower sideband power from -14dBc to -10dBc has resulted in marked improvement in HD coverage outside our 54 dBu contour” said Richard Cassidy, Director of Content Operations for WAMU. Richard also observed coverage on a drive from Blue Mountain, 70 miles outside of Washington, D.C., to Rockville, “Starting from the western slope of Blue Mountain at the 1800 foot level I was able to enjoy the Big Broadcast rebroadcast on HD-3 all the way back to Rockville. So I caught Dragnet and a good Gunsmoke episode and most significantly I had no dropouts from Delaplane all the way back. Solid in Gainesville and Centerville. Very cool!”


John Holt, Chief Engineer (left) and Richard Cassidy (right) at WAMU

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% 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.

Peter Conlon, President and CEO of Nautel said, “We are delighted to participate in this ground breaking work with WAMU. Our mission is ‘making digital radio work’ and with WAMU we’re showing how Nautel technology can help bring the digital radio experience to more listeners in an expanded digital coverage area”.

Read more about this story in the Digital Radio Showcase, by Hal Kneller: 11-17-2010 »

Read more on this story from RADIO WORLD Online, 09.28.2010 »

About Nautel
Nautel is a global leader in the design, manufacture, sales and support of high power Radio Frequency (“RF”) products for AM and FM broadcast, navigation, industrial and space-based applications. With a long history of creating highly innovative products, Nautel continues to lead the way in providing valuable new solutions for the digital radio broadcast revolution. Thousands of customers in more than 177 countries have discovered that Nautel delivers world class RF solutions – systems that meet stringent quality standards at its ISO 9001-2008 registered manufacturing facilities.

About WAMU 88.5
American University’s radio station since 1961, WAMU 88.5 is the leading public radio station for NPR news and information in the greater Washington, D.C., area. With more than 735,000 listeners in the Washington-Baltimore region, WAMU 88.5 is “your NPR news station in the nation’s capital.” WAMU also broadcasts from 88.3 Ocean City on the Delmarva Peninsula and in Washington on three HD channels — the flagship frequency at 88.5–1; WAMU’s Bluegrass Country, a bluegrass and Americana station, at 88.5–2; and Intersection at 88.5–3, a station where new music, science, and stories converge. For more information, visit

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For more information please contact:

John Whyte
Marketing Manager
902-802-0813 (mobile)
[email protected]
Making Digital Radio Work.

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