Rex. W. Minckler, 85, a retired Army colonel who was chief of the Signal Intelligence Service in Washington when the United States entered World War II, died Nov. 2 at the Loudoun Memorial Hospital in Leesburg.

Col. Minckler, who was born in Omro, Wis., enlisted in the Army Coast Artillery in 1914. During World War I, he was commissioned in the infantry and became a company company commander in France. After the war, he transferred to the Army Signal Corps.

After service at various military posts in this country and the Panama Canal Zone, he was assigned to the War Department as chief of the Signal Intelligence Service. This unit was involved in breaking the Japanese Code Purple, one of the important intelligence feats of World War II.

Later in the war, Col. Minckler served in North Africa and Italy. Before his retirement in 1946, he helped establish the Signal Intelligence Service at Arlington Hall.

Following his retirement from the Army, he was a farmer and real estate agent in Waukesha, Wis. In 1966, he moved to Leesburg, where he was secretary-treasurer of the Izaak Walton League, a member of the American Legion and a trustee of the St. Andrew Presbyterian Church. He also was a member of the Army-Navy Country Club.

Survivors include his wife, Jane W. Minckler of Leesburg; two sons, retired Army Lt. Col. Rex D., of Arlington, and retired Air Force Col. Homer R., of Los Angeles; four grandchildren, and two great-grandchildren.