After fielding thousands of questions from the curious, the friendly and the nasty in the remote audience of his English-language "Moscow Mailbag" radio show, host "Joe" (for Iosip) Adamov has refined the essence of his popularity to this:

"Alternate the meat with the gravy... That's the secret of the thing."

In Adamov's case, the "meat" might be a carefully researched answer to a listener's question about the theory of Marxism, while they "gravy" might be, as he said in an interview, "something from everyday life, like the price of gas, or about Jewish problems."

He has been hosting the radio show for almost 22 years, his pleasant baritone and uterly colloquial American English broadcast weekly via short-wave transmitters into North America and Britain.

The show is part of the free-of-charge radio Moscow effort to "present the Soviet Union in a friendly way," as Adamov puts it, to Americans and other capitalists.

Customarily, Adamov handles about 15 questions on his 15-minute program, more or less equally divided between light and heavy topics, but all of them nourishing, he hopes.

A rotund, gray-haired Armenian (his father Russified the name from Adamyan), Adamov, 58, is one of five English-language announcers within Radio Moscow's North American section.

"I swim in both languages equally," he says and the ear would place his origins near a large, Midwestern city, where the language carries a selfconfidence borne of a heartland.

In fact, he learned his English at a school here in Moscow, set up by the state to teach the children of hundreds of Americans who had flocked here in the late 1920s to help with the industrialization of the new Soviet Union.

"They had all these American kids running around and had to do something with them," he recalled, so the school was formed. Adamov, who had first started picking up English during his parents' postings abroad, swam in the American linguistic stream. From there he went to a Soviet high school and then to the Language Institute to study English. He joined Radio Moscow in 1941, the year the Germans invaded, and has been with it ever since.

Adamov has achieved a limited exposure beyond his radio show. In recent years, both the Mike Douglas show and the A.M. America show have done segments from Moscow and featured him as a Soviet analogue to familiar American talk show hosts.

But Adamov's attempts at U.S. travel have been thwarted, he says, by unexplained visa refusals from the State Department He made it once to Boston in 1967, but has not been back since, although he had hoped to be a spieler in an exhibition called "Soviet Woman," scheduled for Baltimore and other cities.

Instead, he has consoled himself with occasional trips to Canada, where he sometimes watches American television.

"What strikes the Soviet eye and ear is that there's a lot of daytime nonsense," he asserted.