The transmission of radio signals of any kind was merely an experimental pursuit in Hungary until late 1925 - and listening to radio over the air, or having privately owned amateur equipment - was forbidden. All of that was to change later that year with the start of the first Hungarian public radio broadcast on 1st December. One hundred years later, amateurs in Hungary are celebrating Hungarian Radio Day, when radio was permitted there.

Nine special callsigns - all beginning with "HG100" - are on the air throughout December until 31st, operated by amateurs from the Hungarian Radio Amateur Society and the Honfy Jozsef Radioclub. Contacts have been made since the 15th of November on CW, SSB and the digital modes on 160 to 10 metres. The operators are also making use of the QO-100 satellite.

The Hungarian Radio Amateur Society website has a full list of the nine callsigns and more details about how to receive a commemorative certificate.