Successfully installed on a KX2. Make sure you change the RS232 speed to something less than the default used by the utility (38400). I used 9600 in the setup of the KX2 under RS232. It works fine. I plan to do it next on my KX3. The KPA500 is not bothered by the TX being out of band. Test it on a dummy load as it will not be resonant on your amateur antenna otherwise without using an impedance matcher.