Why does the creation of a TNF line it up roughly in the middle of the receive passband rather than on the indicated frequency? I can see one good reason - that's where a tone is most likely to cause a problem if it pops up in the middle of a QSO. The downside is that if I line up the RX cursor with the offending signal and then create a TNF, it lands 100 Hz (CW) or 1300 Hz (SSB) above the carrier freq. And, there doesn't appear to be any way other than the mouse to move the filter, and the adjustment steps are odd numbers (like 119 Hz) making it difficult to get it directly on a narrow carrier. Just wonderin'!