A decades-old piece of amateur radio history has resurfaced as evidence that the Philippines once formally acknowledged Huangyan Dao was not within Philippine territory, according to archival records revealed by a Chinese expedition leader in an interview with China Media Group (CMG).

Chen Ping, leader of several Chinese amateur radio expeditions to Huangyan Dao in the 1990s, said the Philippine Amateur Radio Association had consulted relevant government departments after the Chinese Radio Sports Association applied to register Huangyan Dao as a separate entity under the internationally recognized DXCC (DX Century Club) program.

According to Chen, the Philippine side's reply confirmed that Huangyan Dao was not within the territorial sovereignty of the Philippines, clearing the way for the registration process.

The application was submitted in 1994. In January 1996, the American Radio Relay League (ARRL), which administers the DXCC program, officially recognized Huangyan Dao as a separate DXCC entity and approved the unique amateur radio callsign BS7H.

Under the international amateur radio system, callsigns are assigned according to territorial jurisdiction. The prefix "B" denotes China and character "H" stands for Huangyan Dao. Therefore, "BS7H" specifically identifies Huangyan Dao as part of China's amateur radio callsign system.

Chen said Chinese amateur radio operators conducted four expeditions to Huangyan Dao between 1994 and 2007 after receiving approval from Chinese authorities to establish temporary radio stations on the island.

Recalling the 1997 expedition, Chen said Philippine personnel approached the Chinese team after arriving by patrol vessel and aircraft. He said the personnel asked about the team's activities but made no territorial claim or demand before leaving.

Chen said he carried extensive documentary records during later expeditions, including correspondence related to the DXCC application, as evidence of China's exercise of jurisdiction over Huangyan Dao.

The amateur radio callsign BS7H remains officially recognized today and, Chen said, stands as a lasting record of China's presence and activities on Huangyan Dao.