btw its Q to spot on pc >_< and you can ask for medkits or ammo by pressing Q while you are looking at a medic or assault kit user :)
and at the UAV press F to descend and R to ascend

[youtube:3tk6pqs7]http://www.youtube.com/watch?v=zcZ3wXF3r14[/youtube:3tk6pqs7]

hope this helps you :)