Dr. Louis A. Gebhard, 85, a former superintendent of the radio division of the Naval Research Laboratory and an early researcher in radio and radar, died Thursday at Greater Southeast Community Hospital after surgery for an abdominal disorder.

Dr. Gebhard, who was born in Buffalo, got his radio operator's license in 1910. During World War I, he served in the Navy at the Great Lakes Naval Radio Station. In 1919, he moved to Washington and joined the old Naval Aircraft Radio Laboratory. In 1923, he transferred to the Naval Research Laboratory and remained there until his death.

In the course of his career, Dr. Gebhard developed inventions on which he held 92 patents, according to the NRL. In the 1930s, he helped develop the first radar to become operational on Navy ships. For this he received a Certificate of Merit from President Truman in 1946.

From 1945 until 1966, Dr. Gebhard was superintendent of the laboratory's radio division. From 1966 until last year, he was a consultant in the electronics division. He then was a consultant in the technical information division.

Dr. Gebhard attended the Marconi Radio Institute in Cleveland. He earned a doctor of laws degree at Georgetown University and a bachelor's degree in electrical engineering at George Washington University.

Until the death of his wife, the former Marguerite A. Strauss, in 1977, he lived in Washington. Since then he had lived in Temple Hills.

Survivors include a daughter, Katharine Stevenson of Bethany, Conn., and two grandchildren.