The SA-3 Story..
Awacs has lost the Radarkontact to MH17 at 14.52CEST. The Accident happend about 28 Minutes later. So the MH17 was at 14.52 ~450km away from the Accident Point in the Area Tscherkassy. Tscherkassy Distance to Poland/Romania is about 500km. And thats the Radar Range of the Awacs. So Awacs canīt detect Radar Signals at the Area of Donetsk.
dip21.bundestag.de/dip21/btd/18/025/1802521.pdf
MH17 - Malaysia Airlines - Flight history - Flightradar24