Question re Mark V on CW: Is it possible to install just the 3d IF 250 Hz filter? In other words, when pressing "Narrow 2" you get the 500 Hz filter in the 2d IF and the 250 Hz filter in the 3d IF? Or do you have to have a filter in the 2d IF also for "Narrow 2" to work? 73, John, W3ULS