Originally Posted by IO540
Widespread Mode C usage also happens to make a radar information service (RIS) considerably better than the present RIS which, due to the majority of targets being non-C, is close to useless.
"Close to useless"? a bit of an extreme view IMHO. I'd rather be told there was traffic in my vicinity even if in reality there is no factor due to it's altitude. I usually fly in a glider and military 'rich' environment, types which climb and descend very quickly and I would imagine that ATC would have a very hard time informing us of the exact situation at a moment in time. To be informed there is traffic in my area with a half decent range accuracy is good enough for me.
Why is this "Close to useless"?
'any plane not fitted with Mode C from day 1 would be useless for all except the most local bimbles'? Define a 'most Local Bimble'?