Radio Free Europe's operation in Portugal is looking to a solid future having survived revolutionary turmoil and sporadic press campaigns through its 26 years of existence.

Even during 1974 and 1975, when Portugal appeared on the verge of becoming a Western outpost of Moscow-style Communism, it was remarkably free of harassment, without any of the sabotage threats, internal disruption, or sequestration of directors that plagued other foreign entities in Portugal during 1975.

RARET, as the Portuguese branch of FRE is known, is a company of Portuguese and American shareholders who receive no remuneration for their shares. It funnels $200,000 a year into Portuguese government coffers and valuable foreign currency into the economy through staff salaries.

It began operation in 1951, in the days when the Central Intelligence Agency covertly financed the operation of RFE and its sister organization, Radio Liberty.

A monitoring station was set up in Lisbon itself, manned by East European emigres and Portuguese technical staff. Its high-potency shortwave transmitter, designed to bypass jamming, was located in the Ribatejo flatlands east of the capitol.

Its task is to broadcast news, current affairs and light entertainment, relaying programs compiled in Munich conveying the Western way of life, to East European countries.

Until the April 25, 1974, military coup, the RFE installation operated, under the governments of Antonio Salazar and Mercello Caetano without any hitch. Even since the revolution; however, fears about the increasing potency of the Communist Party which controls 85 per cent of the labor force, and of the extreme left failed to materialize.

When the RFE contract came up for renewal in 1975, the military junta, then running the country, ruled that the operation should be allowed to continue.

A workers' commission set up by RFE staff after the coup made sure that the 284 RFE jobs are protected.

The latest contract, signed Feb. 15, provides for compensation three to four times higher than Portuguese law requires for layoffs, a shutdown or dismissal without just cause.

The new contract calls for RFE to pay the government $200,000 a year for use of Portuguese territory. In addition, RFE's annual salary bill of $2 million helps Portugal get foreign currency it needs desparately for its balance-of-payments deficit, now more than $900 million.

The fee is to escalate if RFE increases operations, and President Carter's recent call for increased broadcasts - denounced last week by the Soviet Union - has spurred plans to install seven new transmitters starting three years from now.

RARET has also tried to improve social conditions in the still-backward Ribatejo region. It has set up medical services available to the villagers of Gloria and Castanhia, once afflicted by congential syphilis and appalling living conditions. It has established an industrial school for 250 pupils from the villages, with free lunches for the poorest and modern educational techniques.

The Portuguese Communist Party, meanwhile, refrains from taking public stands against RFE, although it discreetly hints that its presence is not desirable. The Communist-backed and far-leftist press has also circulated the view that a recent $300 million U.S. Treasury loan to Portugal was tied directly to renewal of the RFE contract.

But the money the operation provides is a substantial sum in a country that is economically crippled, and for the foreseeable future it appears free of the official Communist protests that are frequently made against RFE in Munich.