Tuckerton, NJ
From Wikipedia:
The Tuckerton Wireless Tower (39.5585°N 74.3706°W) was built in 1912 by the German "Hochfrequenzmaschinen Aktiengesellschaft für drahtlose Telegraphie" company (The High Frequency Machine Corporation for Wireless Telegraphy, often referred to as HOMAG) when the present-day Mystic Island was called Hickory Island.
The tower was used to communicate with an identical radio telegraph station in Eilvese, Germany starting on Jun 19, 1914, less than two weeks before the assassination of Archduke Ferdinand. The station continued to communicate with Eilvese until America entered World War I on April 6, 1917. It is rumored that it was used to send the message to order the attack by a German U-boat on the RMS Lusitania. After President Wilson's Declaration of Neutrality, the President ordered the US Navy to take over the station on Sep 9, 1914 to assure the neutrality of messages sent to and from the station; however, the station continued to be operated by German nationals employed by HOMAG and continued to communicate only with the Eilvese radio station.
When America entered the war, all U.S. radio stations were seized and shut down by Executive Order. The Tuckerton Radio Station was assigned to the US Navy, which used it primarily to back-up the communications of the US Navy's main transatlantic radio station in New Brunswick, New Jersey. The remaining German personnel at Tuckerton became war prisoners and were replaced by Navy personnel when the U.S. entered the war.
After the war, the Tuckerton Wireless Station was included in German war reparations paid to America. Shortly afterwards, it was sold to RCA, which operated it until 1948 as a backup to their Radio Central facility in Rocky Point, New York. In 1921, RCA installed two massive Alexanderson alternators, which were removed in 1948.
For transatlantic communications, the radio station operated under the call signs WCI and WGG. For coastal communications, after World War I, the station operated under the callsign WSC. The 680-foot steel tower, anchored by three large concrete blocks, was taken down on December 27, 1955.
The three huge anchor blocks still exist today, in a backyard on North Ensign Drive and in the middle of South Ensign Drive and Storysail Drive. Many smaller anchor blocks providing foundations for smaller towers that supported the umbrella antenna are still visible in the lagoons. Remains of the tower can be seen in scraps at the Giffordtown Museum.