An FBI agent testified today in the espionage trial of former Navy communications specialist Jerry Alfred Whitworth that notes on Navy operation plans for the Western Pacific, Sea of Japan and a 1982 intrusion into Vietnamese waters were found in the home of Whitworth's chief accuser, admitted spy John Anthony Walker Jr.

The government has said in previous testimony that Whitworth had access to such classified documents. The government charges that Whitworth supplied the information to Walker.

The indictment in the case claims that Whitworth met in San Leandro, Calif., with Walker in June 1983 to deliver classified information. A brown envelope containing the operation plan for fleet exercises in the Pacific was dated June 4, 1983, according to FBI agent Phillip Butler.

Among a large number of documents made public today were notes and diagrams of some cryptographic machines used for decoding and encoding Navy communications.

Whitworth is charged with passing key cards and keylists used to set the codes within the machines on a daily basis.

Also among the documents was a letter allegedly written to Walker by Whitworth in 1975 from Diego Garcia, a communications station in the Indian Ocean.

The letter reads, "I finally made my first dive but the future is problematic . . . . Man, most of the things are so dated."

The government claims this was a cryptic message about Whitworth's collection of classified data; the defense claims it was a reference to scuba diving.

Some of the handwritten notes shown to jurors suggested that Walker was planning to expand his spy ring, which included his son Michael and his brother Arthur.

"I plan to make myself known to a larger regiment of government and civilian organizations to see what's out there. For example, the CIA," said one notation.

Also yesterday, Judge John P. Vukasin Jr. ruled that defense lawyers may question Walker about a cache of weapons, including canes with concealed guns and knives, found at his home. John Walker is expected to testify next week.

Whitworth, 46, who served as radioman aboard two aircraft carriers, is accused of passing Navy cryptographic secrets to the Soviets through Walker's spy ring for nine years and receiving $332,000.

The prosecution alleges that Walker recruited Whitworth as a spy, but Whitworth says he is innocent and is being used by Walker as part of a plea bargain. Walker pleaded guilty to espionage charges last October in exchange for more lenient treatment for his son, who also pleaded guilty to espionage.