Hello, I have an M175 that I just replaced the MRF455 with Ma-COM 455s(matched received from reputable source in SD). It is acting peculiar. The SWR is only good 1.2/3 on low. . Up in the 3 area on Med and High. Also any modulation on med or high results in the keying relay clicking. My SWR meter is after the M175. I have tried 6ft and 8ft jumpers between the radio and assistant with similiar results. My dead key is set between 2-3W. It runs another 2 455 and 2 1446 just fine(no swr issues)....
M175 High SWR
M175 High SWR