Good day, <<<I saw a lot of UR RSQ 599, instead of RST. What is meant by RSQ?>>> See the below web page regarding RSQ and its history. http://rsq-info.net/ The RSQ format has been approved for digital modes by regions 1 and 3 of the IARU. It started out primarily for PSK but can be used for reporting most digital modes. Bob K6MBY Sequim, WA