So.... on HF it makes no difference if I use BNC or SO239. My MP has so239, that's a fact. My HF antennes + coax have PL239, a fact in my case (in my 30 years of ham radio always used them and they never failed me) The K2 has BNC, that's a fact. A simple bnc-so239 adapter is permanently connected to the bnc of my K2. Problem solved. 73 Arie PA3A