Light Bringer solution is probably useful here too..
First, activate the three linked Absorption Units required for whichever beacon you're going to start with. Once all three AU's are activated, you should see the three lasers from the AU's intersect in the sky above the drop-point for the beacon. If one of the lasers is missing, then it's obstructed and you'll need to go and blow up the obstruction (a billboard probably) before you can call in the chopper to drop the beacon...
Run to the beacon's drop point - shown on the map, or just underneath the intersection of the three AU lasers in the sky - and call for the beacon to be dropped off... A few seconds later, the beacon will drop, and the timer will begin... You need to defend the beacon from inbound freaks for a couple of minutes. Target the freaks with the yellow 'splat' symbol above their heads as they're the ones who will do the most damage to the beacond (they're shown on your radar too!) Don't worry about using explosive ordinance, you won't damage the beacon...
After a couple of minutes, you will be told the beacon is charged, a small cutscene will follow showing the beacon toasting any nearby freaks, and pop goes the chievo!