What are easy ways to get the harrier strike on modern warfare 2?

I want to get a nuke i got everything ready for it but the one problem is i can't get the harrier quick. I don't know how people do it but when I play domination or something like that about 2 minutes or less i hear "Friendly harriers inbound". I always think how the hell do they do that. I tend to go away from my team mates and I'm wondering if that's wrong. I also tend to sprint a lot but I'm not sure how your going to get lots of kills. I use the scar-h (I'm not changing that) while sprinting. Should I be more cautious but I'm not sure how to be really aware of my surroundings. I play a lot of hard core games and I'm also wondering how you should play that because everyone camps and if run two feet your dead. By the way I don't need tips on weapons, perks, attachments just the harrier stuff and hard core play.