The first presence of the U.S. Navy at the Jupiter Inlet was in 1890 when a U.S. Naval Wireless Telegraph Station was established on what was then Fort Jupiter Reservation.
In the early 1900s Naval Radio Station Jupiter became part of a chain of coastal stations created by the Navy. In 1913, Jupiter was further authorized to conduct commercial business transactions by radio.
In 1929 the Navy acquired additional land at Jupiter Lighthouse from the Department of Commerce and established a Radio Compass Station. The station monitored distress signals and naval ship and aircraft frequencies, broadcast weather information and served as a navigational aid. Ten years later when the U.S. Coast Guard managed the site, the Navy obtained additional land and built a high frequency direction finding (D/F) station nearby.
In September 1939, Germany started World War II by invading Poland. Great Britain, France, Australia, New Zealand, and Canada declared war on Germany. With U. S. involvement expected at any time, the Navy established an intelligence listening post at Jupiter and had eight personnel on board by October. After April 1940 the station was expanded into a “Strategic Observation Post,” consisting of a Communications Radio Intelligence Unit and Radio Direction Finding Station know as “Station J” and any pretext of neutrality by the United States was abandoned and Jupiter was acknowledged as an intercept and D/F station.
In 1941, with 30 servicemen in residence, the Navy received 3.5 more acres to complete the station. Twenty-six buildings were included in the final build-out. Two advanced direction finders were also added about two miles south of the station on U.S. Highway One.
Following the attack on Pearl Harbor by the Japanese, Station J began intensive radio monitoring of enemy radio traffic. In February 1943 Station J was manned by 95 personnel, including 12 Marines assigned as security guards. Station J monitored German U-boat traffic, intercepted their radio activity and forwarded the intercepted material to Washington for code breaking and translation (Naval Communications Annex on Nebraska Avenue where the U.S. BOMBE was installed to read the German Enigma traffic).
Thirty German U-boats were destroyed off the Florida coast in May 1943 and an additional 37 were destroyed in June 1943. Many of these U-boats were identified and located thru the efforts of Jupiter.
As the war wound down, the need for Jupiter decreased, and on 15 July 1945 Station J was decommissioned and reborn as Coast Guard Radio Station NLM.
The pictures below were taken in January and February 1945 prior to the station closing in July 1945:
DIRECTION FINDING OPERATING ROOM