G.M. Agrees to Sell Its Satellite TV Unit In $26 Billion Deal
General Motors, in deal certain to draw scrutiny from regulators, will sell Hughes Electronics, owner of DirecTV, to EchoStar Communications for about $26 billion in cash and stock; sale would combine nation's two largest satellite television companies, creating behemoth with 16.7 million subscribers or more than even biggest US cable television company; EchoStar would control more than 90 percent of satellite television services for homes in US; combined company would use EchoStar name and adopt DirecTV brand for services; likely opposition to merger by federal regulators discussed; opposition by at least 10 members of Congress, including chairmen of several powerful committees, noted (M)