A Falls Church man was convicted in U.S. District Court in Alexandria yesterday of illegally exporting high-technology electronics components to Austria, possibly for eventual shipment to Soviet bloc nations.

A jury found Guenther R. Nachtrab, 43, guilty of 10 counts of conspiring to ship and actually shipping integrated circuits and other electronic parts without export licenses.

The components, worth about $40,000, were banned from export because they could have both military and civil applications, said Thomas M. Buchanan, assistant U.S. attorney.

Some of the parts could be used for guidance in such weapons as "smart bombs," cruise missiles and sidewinder missiles, and others could be used in telecommunications gear such as radar, he said.

Three other defendants indicted along with Nachtrab remain at large because they reside in Europe. No extradition provisions exist for alleged violations of national security export controls, said Theodore Wu, deputy assistant secretary for export enforcement in the Department of Commerce.

Buchanan said Nachtrab operated a small Falls Church firm known at various times as Text Editing Equipment, The Electronics Exchange, or TEE.

He told suppliers from whom he bought parts that he planned to use the components either in a non-existent West Virginia manufacturing plant or for a non-existent contract with the CIA, Buchanan said.

In reality, authorities charged, some parts were sent to the Vienna, Austria, firm of Steuerungstechnik und Messgeraete (SMG), run by Anna Landau-Wellems and her daughter, Jeanette Wellems, who were also named in the original indictment.

Nachtrab, in one instance, shipped parts to a West German firm, Contacta, for reshipment to SMG to avoid licensing requirements, Buchanan said. Contacta is operated by Klaus Talleur, another defendant who has not been brought to trial.

Records of communication between SMG and Nachtrab indicated that the components were intended for Soviet bloc countries, Buchanan said. One specific reference was to a client in Budapest, Hungary, he said.

Landau-Wellems once operated a firm placed by the Department of Commerce on the embargo list because of suspected dealings with Soviet bloc countries, Buchanan said.

The conspiracy to evade export regulations began in July 1981 and continued until March 1982, with the illegal shipments made between January and March of 1982, Buchanan said.

Investigations began in March 1982 after two employes of Nachtrab reported to authorities that goods were being exported by their firm without proper papers. The value of the shipments on invoices was marked down to avoid licensing required for more valuable shipments, they said.

A 20-count indictment against Nachtrab and the other three defendants was returned April 14.

Nachtrab was acquitted yesterday on one of the counts, and nine counts were dismissed during the course of the trial by Judge James C. Cacheris. Nachtrab was convicted on the other 10 counts. Sentencing was set for Sept. 2.