Communications and Power Industries to Supply High Power Amplifiers for XM Radio's Digital Audio Radio Via Satellite (DARS) Program;.

Business Editors/High Tech Writers

LAS VEGAS--(BUSINESS WIRE)--April 11, 2000

Contract Approaches $14 Million

Communications and Power Industries (CPI) Satcom Division, Palo Alto, Calif., the worldwide leader in satellite communication high power amplifiers (HPAs), announced that it has signed an agreement to supply equipment to supply equipment to Unique Broadband Systems, which in turn will provide equipment to Hughes Network Systems for the XM Radio DARS system.

The announcement was made at the National Association of Broadcasters Convention in Las Vegas.

The HPAs are an essential element of the terrestrial wireless portion of the XM Radio satellite service, which will provide digital-quality audio programming across the United States.

The contract is valued at nearly $14 million.

"CPI is excited about the opportunity to apply its cutting edge design technology to such a groundbreaking satellite application such as XM Radio," said Rick Schaffzin, CPI Satcom's president and general manager. "We're very proud that the Unique Broadband Systems/Hughes Network Systems team chose us as a partner in this next generation broadcasting venture."

Alex Dolgonos, President & CEO of Unique Broadband Systems, said, "We are pleased to have selected CPI to work with us on our contract with Hughes. CPI has demonstrated a strong expertise in producing HPAs, which will form an integral part of the network to be constructed by Hughes."

CPI's high power amplifiers incorporate leading edge, multi-stage depressed collector (MSDC) klystron design, providing major efficiency improvements and excellent linear performance. The efficiency improvements provide significant operating savings due to both reduced prime power requirements and increased life expectancy, as the klystron runs cooler than single collector designs. Modular design of the power supply and monitor and control sections contribute to improved reliability, sparing simplicity and fast MTTR.

Unique Broadband Systems, Inc. is a recognized leader in the design, development and manufacture of broadband wireless solutions. With headquarters in Concord, Ontario, Unique Broadband Systems markets its products globally, focusing on the key areas of COFDM-based High-Speed Mobile Solutions (DAB, SDARS, and Mobil Multimedia) and Wireless Video, Voice and Data Systems (MMDS, MVDS, LMDS). UBS's diverse and evolving product portfolio is combined with system design, installation, maintenance and technical support to provide its customers with total system solutions. Unique Broadband Systems is a trademark of Unique Broadband Systems, Inc. For additional information, visit UBS's web site at http://www.uniquesys.com .

Hughes Network Systems, headquartered in Germantown, Maryland, near Washington, D.C., is a unit of Hughes Electronics Corporation and a leading supplier of broadband satellite and wireless products, services, and networks. HNS is a world leader in the manufacture of very small aperture terminal (VSAT) satellite networks with more than 300,000 VSATs installed worldwide and is one of the largest manufacturers of DIRECTV direct-to-home satellite television systems. HNS provides DirectWay(R) broadband, IP-based services to the enterprise and DirecPC high-speed satellite Internet services to the consumer. The earnings of Hughes Electronics are used to calculate the earnings per share attributable to the General Motors Class H common stock (NYSE: GMH). For additional information, visit the HNS web site at http://www.hns.com .

XM Satellite Radio Inc. is developing a new band of radio. Beginning the first half of 2001, XM Radio will beam up to 100 channels of digital-quality music, news, sports, talk and children's programming directly from its two powerful satellites to vehicle, home and portable XM-Ready radios coast-to-coast for a monthly subscription fee of $9.95. American Mobile Satellite Corporation holds controlling interest in the company. XM Radio is backed by a group of industry-leading strategic investors, including General Motors, Clear Channel Communications and DIRECTV, respectively the leading car, radio and satellite TV companies in the U.S. First there was AM, then FM and soon ... XM Satellite Radio. For more information, please visit XM's website: http://www.xmradio.com .

CPI Satcom Division manufactures and supplies high power amplifiers and networks for satellite communication uplink and high power wireless applications. As the acknowledged industry leader, CPI has shipped over 14,500 amplifiers to 156 countries worldwide, and supports its customers with an unsurpassed 24-hour service network. CPI Satcom is part of Communications and Power Industries, a market leader, providing leading edge technology for the broadcast, wireless, satellite, medical, radar and decoy markets. For further information, please contact Gerard Charpentier, CPI's VP of Operations, XM Radio Program, at [phone]. CPI Satcom's website is at http://www.cpii.com/satcom .

National Association of Broadcasters, CPI Booth numbers L7107 and T2345