Two House subcommittees yesterday opened debate over what, if anything, Congress can do about the early reporting and projections of election results, a touchy subject on the West Coast last fall when television reporters declared Reagan the winner of the presidential election before the western polls closed.

Executives from the nation's three major networds denied vehimently in their testimony that news coverage of the 1980 presidential vote had anything to do with lowering voter participation. They declared Congress would be interfering with the First Amendement if it tried to limit such reporting.

Rep. John L. Burton (D-Calif.) suggested "it was President Carter going belly up early in the evening that discouraged voters from voting," rather than any network reporting.

However, Rep. Timothy E. Wirth (D.-Colo.), chairman of the House telecommunications subcommittee, scolded the network representatives for failing to address the fact that "lots of people feel their rights have been infringed on" by early election results reporting. And Rep. Cardiss Collins (D-Ill.) said the networks "did a disservice."

Several bills have been introduced with different solutions to the problem: requiring the uniform opening and closing of polls despite the East to West Coast time difference; changing election day to a Sunday; or restricting the announcement of East Coast election results before western polls close.

The networks have rejected a proposal that they voluntarily refrain from projecting winners and losers, and only report actual results after all polls close.

NBC President William J. Small said "election night vote projections have never been demonstrated" to have any effect on voter turnout. Turnout was up in nine of 13 states in the Pacific and Mountain time zones and even in California 75.6 percent of registered voters voted last November.

"It would be wrong," Small added, "to adopt solutions for what may be a phantom problem."

CBS News President William A. Leonard told the subcommittees, "We cannot patronize our audience by withholding from them what we know." The causes of low voter participation -- 53.9 percent of eligible Americans voted in 1980 election -- range, he suggested, from "the complexity and frustrations of modern life, to a growing disrespect for institutions, to a sense of alienation and despair about the value of the vote, to impatience with the political and electoral process, to a lack of faith in -- or respect for -- the candidates. . . ."