OK. So I'm using my IC746PRO which I know is pretty close to where it should be on frequency stability. RBN CW has confirmed and I've worked very narrow 50-250hz plenty of times. Have you ever looked at the output on waterfall scope? Try this... download Speclab and run speaker out to your line-in from your 101e. Where does the filter start and end? Attached is a picture showing where my signal (the 800hz) is and me transmitting back to myself on the 746PRO notice how far away it is. If I turn the USB RX I can get it close but then notice how the filter shifts. This also affects the general noise level I have noticed and is no longer consistent with LSB/USB settings on where the filters begin/end. Second picture is now adjusted to be pretty close to each other Notice now how my tone and the receive tone is now on the edge of the filter. This is no good. Have you ever verified if you transmit dead-on say 14.100 into a dummy load then transmit back to yourself and viewing it in a waterfall display like this to see if its actually zero beated?