ARDF, Amateur Radio Direction Finding), Korea
Argentina
Australia, printed letter, no stamp
Bosnia Hertzegovina
Costa Rica
Costa Rica
Costa Rica
Croatia
New Caledonia
French Antarctic
French Antarctic
Indonesia
Indonesia
Indonesia
Israel
Japan
Japan
Finland, own stamp, 2009 Tanja, OH8HDL and Markku, OH8UV
Finland, own stamp, 2013 Raimo, OH3BHL and Jukka, OH9TT
Liberia
Liberia
Liberia
Liberia
Norfolk
Norfolk
Norfolk
Oman
Oman
Poland
Romania, printed card, not stamp
Romania
Slovenia
Srilanka
Switzerland
USA
USA
USSR
USSR
USSR
Yugoslavia