on the channel input for example
If you are on say 19-1 and hit say channel 4 - a popup screen appears and gives you all the options with 4 in it 4.1-4.2-43.1, etc. You then just move over and pick the one you want or add more numbers, so if you wanted 43.1, you would just hit the 4 then 3 and all variations of 43 would be in the popup.
Ex. Say I was on channel 2.1 and I input 19 - a box pops up with 19-1 highlighted, I hit enter and it goes to 19-1.
Most also use the psip guide, which works fairly decently, not perfect but not too bad for most channels - it is more the channel than the tuner in most cases.