Well, if I look at my friends, or at least, people with whom I get along fine, 5 of them in total;
2 have an official Asperger's diagnosis, 1 is on the High functioning autism spectrum, 1 is so obvious, but he doesn't need a diagnosis because he's doing fine without it (in getting a degree and all) and another one, my girlfriend, is pretty much so obvious, but they're still sorting out what exactly her deal is. But diagnosis imminent so to say.
That's the motley crew I get in touch with when I'm not online. So... yeah, for me, I think I kinda have that radar, lol
The bigger problem I feel is; how much time I do want to spend with non-aspies (or at least people that are NOT on the autistic spectrum), that will not last, it never has. It's one of those cases, that if you can last long enough with me, chances are you're an aspie. In the past, the only stable "friendship" I have held besides ones I mentioned earlier, was a long-term relationship, and looking at myself and other people on the spectrum, I'm quite sure she'd qualify as an aspie as well... and to top if off, she's the sister of that one guy who doesn't need his diagnosis cause he's doing fine with whatever it is he does.
Me and NT people is a terrible match... the only NT people (and even take NT with a grain of salt) with whom I can get along "decently fine" are my parents, and even my mom took courses in child psychology to get along with me when I was younger (not neccesarily because she wanted to know what was wrong, but more in a way on how to handle me, my anger issues and my self-harm issues). And my dad suffered from major brain trauma about 10 years ago, so he's equally messed up (in a good way). I never got along well with him before.
So in that sense; yes... if people aren't put off by how I am, and to some degree can identify with me, we're going along fine... it's just identification goes only that far. Most of the time there's this point... a tipping point, and that's where people break off. If you can stay past that crucial point, better make an appointment at the local therapist.