Various "special event" callsigns are issued for periods ranging from a day to a month, either for individual radio contest days or commemoration of specific current or historic events. Series allocated to an international organization. As a component of their license, amateur radio operators are assigned a call sign that they use to identify themselves during communication. A world championship has been held in every odd-numbered year since then. The 26 letters of the English alphabet and ten digits may be used to form call signs, accented letters excluded. Call sign blocks for telecommunication The International Telecommunication Union has assigned Russia the following call sign blocks for all radio communication, broadcasting or transmission:
It carried solar cells to generate power, and was expected to operate for six months.
In order to save time, two-letter identifiers were adopted for this purpose. Call signs in New Zealand are no longer generally used to identify broadcast stations. This is through a special agreement with the government of Chile, which is officially assigned the CB prefix. The following call sign prefixes are available for future allocation by the ITU. Member feedback about Call signs in New Zealand: Transmitting the letters CQ on a particular radio frequency is an invitation for any operators listening on that frequency to respond.