John, N3DRK wrote: "I would like to trade an Inrad 455khz 250 Hz for a 455khz 125Hz." ========== No need to dispose of the 250 Hz filter. I have the 455kHz 500, 250 and 125 Hz filters in my MP and like it that way. I put the INRAD 125 Hz filter in the 2.0 kHz slot and it works fine there on CW with no other changes. 73, de Earl, K6SE