| 01.05.2010 | 31.05.2010 | 4U | 4U10NPT | The Vienna International Amateur Radio Club (4U1VIC) will activate a special event callsign to promote the "2010 Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons" (NPT). QSL via OE1ZKC. |
| 19.10.2009 | 25.10.2009 | 4U | 4U1UN | United Nations Headquarters, New York - OH2BH, OH0XX, OH2NB, OH6LI, G3SXW, F5CWU, F4EGD, PY5EG, JK3GAD, UA9AB, LA5IIA LA4OFA, NN1N, K2QI, KA2RTD, K2LE, N2UN, N2GA, K2DO, N2YBB, KA2D, WQ2N and W2VQ. |
| 16.06.2008 | 30.06.2008 | 4U | 4U1WED | The Vienna International Amateur Radio Club (4U1VIC) at the United Nations in Vienna is now active using a special callsign. Activity is to celebrate the "World Environment Day" (WED) which took place on June 5th. |
| 22.10.2007 | 16.11.2007 | 4U | 4U1WRC | This activity is taking place from the International Amateur Radio Club station 4U1ITU in Geneva during the 2007 World Radiocommunication Conference (WRC). |