What might be low-level IMD3 in K3. When used with 13 dB KPA-500 the power is 25W. K3 IMD might be considerable lower than KPA-500 IMD3 of -35dB. So this is the result? How about 400Wout and 300W? Lower output might give a clean signal when power is not primordial. Benny OH9NB