My solution for the K2 PTT problem in CW with CT and the Top Ten DX Doubler: unplug the mic connectors! It's worked fine for 4 years so far. On the other hand I have only operated SO2R in CW contests at QRP and 100 watt levels so far (no external amps). IARU and other mixed-mode contests would require Don's solution. 73 Gary, N7IR