Described are techniques for determining optimal antennae for use by wireless radios that share communication resources, such as a radio frequency chain. When communication is initiated using a first wireless radio of a communication device having at least two antennae, configuration data for the first wireless radio may indicate a default antenna. When communication is not taking place using the default antenna, an alternate antenna may be used to communicate test data. Signal strength data for communication by each antenna may be used to determine the default antenna indicated by the configuration data. When communication is initiated using a second wireless radio, separate configuration data for the second technology may indicate a default antenna. Separate signal strength data for communications, by the second wireless radio, using each antenna may determine the default antenna indicated by the configuration data.