An extensive upgrade of the JET radiometer was implemented in 2008 in order to further enhance the performance of the system. Six new high frequency mixers were added, bringing the total number of receivers to twelve. In this way the radiometer provides continuos frequency coverage from 69GHz to 207GHz, enabling the diagnostic to operate over a wider range of plasma conditions. This report describes the changes introduced in the system architecture in order to add the new hardware and gives some illustrative examples of the improved performance of the diagnostic.