4U1UN - United Nations Amateur Radio Club

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4U1UN will be active from United Nations HQ in ARRL DX CW Contest, 15 - 16 February 2025.

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4U1UN will be active from United Nations HQ on 5348 now.

[4L5A]

4U1UN will be active from United Nations HQ on 7076.9 now FT8.

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4U1UN from United Nations HQ on 50323 now FT8.

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4U1UN from United Nations HQ, New York on 21074 now FT8.

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PRESS RELEASE
United Nations Amateur Radio Club Celebrates 77 Years of Global Communication

4U1UN marks major milestones, new technology upgrades, and a strong on-air presence from
UN Headquarters
NEW YORK, October 2025 — The United Nations Amateur Radio Club (UNARC), operating as 4U1UN, proudly marks 77 years of worldwide radio communication from the United Nations Headquarters in New York City. Founded in 1948 as K2UN, the club received its current callsign 4U1UN in 1978 with approval from the UN Secretary-General — thanks to the late Max De Henseler (HB9RS), then UN Chief Cartographer. That same year, De Henseler made the first-ever 4U1UN contact after the station became an independent DXCC entity.

A Legacy Renewed
Over the decades, 4U1UN has participated in major contests and events, including 4U70UN and 4U75UN. In 2015, nine operators logged more than 6,000 QSOs from UNHQ’s North Lawn Garden. After a post-9/11 hiatus, the club was revitalized in 2018 with new antennas and modern SDR technology. Since then, it has logged more QSOs in seven years than in all previous decades combined.
In 2020, Nobel laureate Dr. Joe Taylor (K1JT), creator of FT8, made the first-ever FT8 QSO from 4U1UN. That same year, the Yasme Foundation honored James Sarté (K2QI) and Adrian Ciuperca (KO8SCA) with the Yasme Excellence Award for their leadership. In 2025, 4U1UN achieved a milestone on Club Log’s Most Wanted list, improving from #27 in 2018 to #99 today.

Modern Operations at UNHQ
Located on the 42nd floor of the UN Secretariat Building, 4U1UN operates remotely via a Flex-6600 SDR (courtesy of Flex Radio), ACOM 500S amplifier (courtesy of DX Engineering), ACOM-06AT tuner/switch (courtesy of DX Engineering) and ACOM eBox (courtesy of ACOM) feeding antennas nearly 500 feet above Manhattan. Despite challenging RF noise levels, the station maintains consistent worldwide activity via advanced SDR tools and remote operation.

Recent Technical Advances
Recent upgrades include a new low-band inverted-V for 80 m / 160 m and an M2 6M-3SS 6m beam that logged nearly 2,000 6m QSOs from 37 entities this season. The club also restored its NCDXF 4U1UN/B beacon (operating since 1985) using a Cushcraft MA5VA and Icom IC-7200. Longtime QSL Manager Herbert Aeby (HB9BOU) continues to handle QSL requests, Club Log, and LoTW uploads for operators worldwide.

Looking Ahead
UNARC is testing AI-assisted noise-reduction tools to improve weak-signal reception and boost SSB and low-band activity. "From atop UN Headquarters, 4U1UN continues to symbolize international friendship through radio — connecting people, not politics,” said Metin Serbetci (K2ECE), UNARC President.

About UNARC
Founded in 1948, the United Nations Amateur Radio Club promotes technical excellence and global goodwill through amateur radio. Operating from the UN Headquarters in New York, 4U1UN remains one of the world’s most recognized DXCC entities.