So what is the blue bubble around the Raven? Do you have to get within it to shoot it? I did. Missed getting the salvage though.

That is the ECM effect bubble, units that are inside it receive "ECM Charges" which look like little lightning bolts inside an eyeball icon, and any unit with an ECM charge cannot be targeted for direct or indirect fire ranged attacks. But if the attacker enters the bubble too, that attacker becomes able to target the ECM-protected units.

You can also remove a target's ECM charges by sensor locking it.