When Ramon Dejesus arrived in Washington from El Salvador, he says, his only link with the community was through a spotty patchwork of distant and unfamiliar cousins who had arrived here in earlier years. Like them, he moved in tight circles limited by language and national origin.

Washington Hispanics say that Dejesus' tale is a familiar one, that of a newly arrived, non-English-speaking immigrant unable to communicate in an alien environment. But they also say one thing that has helped them adjust to life here is radio station WMDO-AM, which broadcasts in Spanish over a 50-mile radius from Wheaton.

Dejesus has acquired a little English since his arrival, enough to work as a waiter, but for basic news about weather, politics in Latin America and local events, "Radio Mundo," Washington's only Spanish radio station, is his single media source, he says.

Since it went on the air nearly three years ago, Radio Mundo, ("world radio") has been broadcasting community information to an increasing Hispanic population here, estimated at between 20,000 and 40,000. According to one ratings survey commissioned by the station, up to 45 percent of the area's Hispanic population tunes into WMDO weekdays.

The station, which has a staff of 18, is owned by the California-based Lotus Co., which owns 12 other Spanish stations around the country. WMDO came into existence after Lotus bought Washington's previous Spanish radio station, WDON.

Another listener, Porfirio Medrano, 19, a Catholic University student who moved to Mount Rainier from Panama in 1973, says that Radio Mundo "breaks the language barrier."

"I speak English, but for those who do not, like the older ones, Mundo is the only way they can get information," he says. "My mother speaks only Spanish and she puts the station on every day. She wants to find out what the weather will be or what the news is. She would be lost without it."

Medrano also sees WMDO as a uniting force in the Hispanic community.

"They tell you about events like the Hispanic-American festival this August. . . . It helps pull all the different groups together."

Station personnel say they try to go beyond community announcements. Last winter, for instance, the station "got the word out that Montgomery County's School Board was going to cut its '84-'85 budget for bilingual education," says station manager Allan Klamer.

"But we convinced the school board that the budget is essential to the academic success of many students. We showed for the first time how important an issue was to us."

After the station's publicity drive, Klamer said, nearly 100 persons showed up at a meeting with the school board and pressured it to save the bilingual program. That part of the budget was left intact, he said.

Orlando Arechea, 25, an auto repairman who moved here five years ago from Colombia, said the station's reports of news from Latin America are also a draw.

"They go into more depth with South American news than the other stations because they know that the people listening want to find out what has been happening at home."

For newly arrived immigrants, Arechea said, "the worst problem is the language. With that everything is difficult. But Mundo helps because it explains where you can go to get a job or what to do if you have a problem."

Station manager Klamer says WMDO's daily help-wanted announcements have helped place many Hispanics in jobs that they might not otherwise have known about.

"We have placed people in jobs as engineers, bilingual secretaries and auto mechanics, carpenters," he said. "One time someone phoned us needing a lace seamstress. They had heard that some Hispanic women were skilled in this work. We found them a seamstress. Another time a jeweler called saying he needed a goldsmith. We found him three!"

Since July, Mundo has also been running employment ads supplied by Montgomery County's personnel office.