Four of Czechoslavakia's prominent human rights activists were sentenced today to prison terms ranging from 14 months to 3 1/2 years on charges of subversion, sources close to the defendant said.

Former theater director Ota Ornest was given the stiffest sentence of 3 1/2 years in prison for maintaining "conspiratorial links" with foreign diplomats and agents in France and Italy.

Jiri Lederer, a journalist, received a sentence of three years' imprisonment on similar charges.

Former theater Director Frantisek Pavlicek was given a 17 month suspended sentence after being convicted of slandering the state in articles published abroad. Playwright Vaclav Havel, convicted of trying to smuggle abroad the banned memoirs of a former minister, received a 14-months suspended sentence. Both were put on three years' probation.

It was the biggest trial of dissidents to be staged in Prague for five years. The public prosecutor had requested light sentences for the four, who were all tried behind closed doors. All four defendants said they would appeal. All except Ornest had pleaded not guilty.

All defendants execpt Ornest were among the first to sign the "Charter 77" manifesto calling for human rights to be respected in Czechoslavakia but the prosecution argued that the case had nothing to do with the charter.

Informed sources said more than a dozen other charter signatories were ordered to report for police questioning and were told to stay away from the courthou.

In his sum-up, the prosecutor reiterated that Ornest, 64, and Lederer, 55, had made contact with Pavel Tigrid, a banished Czechoslavak emigre who edits a political journal in Paris that Prague authorities assert is financed by the CIA.

But the prosecutor suggested any sentences against Harvel, 41, and Pavlicek, 53, should be suspended since it was not established in court that they had direct dealings with Tigrid.

All four, in final statements to the court, insisted they were still supporters of the socialist system and had not meant to undermine state interests.

Lederer was interrupted three times, however, when he tried to explain why he had denounced aspects of political policies in his articles criticizing the government, the sources said.