Is the K3 an all-in-one SO2R radio?
The K3 is not SO2R in a box. However, it does have tremendous flexibility with the full-performance subreceiver; the ability to transmit on the main or sub frequency; the ability to use in-line filters to the main receiver via the Rx In and Rx Out connectors, and so forth. For many people, this is essentially SO2R operation.