The point is, and this has been made over and over and over again, is that the damn thing wont go 'ding' if there is no surveilance at the levels it's meant to go 'ding' at
Owen, without trying to sound condescending, DERRRRR !!!!, Never has it been suggested that ATC mysteriously find more RADAR coverage, use what they've got.
If you believe the current RADAR coverage combined with MSAW protection would not have saved the day at Benalla, so be it.
Then comes the ADS-B nay saying, ADS-B will be sending PH (pressure height) data (i.e 1013 mb / 29.92"), whilst this is not on area QNH, neither is Mode C on the SSR, Mode C is also of the same type, if not the exact same PH encoder, do you guys really understand that little about what goes on ?, from my understanding TAAATS then levels all the data with the Area QNH's.
FYI
"You may ask, "how about the altitude reporting part?" Well, the first thing to remember is the Mode C is always referenced to pressure altitude which is 29.92" barometric pressure. The important thing to remember is that you should have your altimeter baro-scale set at the pressure the controller has given you. Now you say, "if my altimeter is set at let's say 30.23" and Mode C is putting out at 29.92 there will be an error on the controllers screen! The controller's computer will take the Mod "C" output based on 29.92" and convert it to barometric pressure at your present position." taken from
Transponders for Dummys
So no, it is not connected to the back of ones altimeter.
So ADS-B should work just fine for MSAW.
The point is Dick there is no point implementing an airspace system if you haven't got the surveilance to provide it.
And that I believe is the main reason NAS made such a big splat with its fall from grace.