The BARS PESA has a search range of 400 KM and a Lock on range of 280 KM
Where as the APG 66 V5 has a Search range of 265 Kms and a Maximum lock on range of close to 135- 140 Kms..
As per the official sources the f-16 with approx. Half the RCS of MKI with its AGP radar will lock on to an MKI at 50- 55 Nms Head on Mode..
By official sources, we can conclude that, the MKI will be able to pick up the f16 few seconds before the f16 can pick up, at such speeds..Because practically that is the time gap u can get to decide..
It will be an interesting contest one on one, only with range and radar detection, though lot of other factors such as payload and maneuovarability comes to play, I"m keeping all that as constant for both fighters for arguments sake..
you may prove me otherwise..