Hoo-frickin'-rah! I finally beat the Spec Op (Homeland Security; Veteran; alone).
--I start out Wave 1 on top of the Burger Town with the sentry turret covering the roof access points, freeing me to snipe to my heart's content with the Intervention (I like the one-shot-one-kill!).
--Once done, I move the turret to the front corner of the Burger Town roof nearest the Taco Joint, surround it with claymores (8, at various locations), and haul ass over to the inside of the Taco Joint.
--In Wave 2 I try to draw the Predator early on, as between its hits, and the active sentry, I wipe out half the enemy in nothing flat; effective sniping and one or two more draws of the Predator gets me down to 5 left, which then converge on my location and are easy to nail
--A critical key to success in completing Wave 2 is ensuring the enemy AI doesn't kill the sentry turret
--For Wave 3, I hustle over to Nate's, get up to the roof, grab more claymores and the unused sentry, and get my butt back down; I plant the sentry in the area between the kitchen and the bar, and camp out in the brick "pantry" area adjacent to the door facing Burger Town;
--Judicious use of mines and effective weapons use (sniping with the Intervention, and close-quarters protection with the SCAR gets me down to the just the chopper
--Before killing the chopper, I draw the Predator, wait out its salvo, then haul ass over to the bank and grab the last sentry; drawing and waiting on the predator once more, I head out the back door of the bank, and back in the back door of Nate's; I place the sentry in the same place as before, and proceed to kill the chopper from behind the podium near the door facinng the bank
--Soon as the chopper goes down, I get up on the roof of Nate's, re-up my mines and my ammo at the ammo box, head back down to the brick pantry alcove, and essentially repeat Wave 3 for Wave 4
--Upon killing all the foot mobiles in Wave 4, I find an RPG, wait out the drone, get to the ammo box to load up the RPG, and take out the BTR with the RPG, usually from the front doors of Nate's
--Wave 5 is real similar to Waves 3 & 4, but remember - the turret on the Burger Town roof is still live, and seems most effective in this wave; once all the foot mobiles are down, I found killing the two choppers tough, since the pilots seem to fly "smarter" (higher - making it difficult to get the Intervetion's scope on them), but patience pays off and 12-15 rounds from the Intervention downs each chopper
--Oddly, the BTR in this wave is easier, at least if camped inside the front doors of Nate's, since he drives in closer to you; RPG takes him out nicely
Boom - you're done!