I'm not sure about gaydar improving from spending time with other gays. It's actually been the opposite for me, so I guess we're all different in this regard.
When I first came out my gay "mentor" told me about gaydar, a term I'd never heard before. I'd never had any routine contact with gay men.
"What's special about that?" I asked him. "Can't everybody do that? I've always been able to tell who's gay, that's obvious."
"DUH!" he replied. "No, not everybody can do it, and not most straights. But you can because you've always been gay, even before you knew you were. The same thing that made you gay from birth also gave you the ability to recognize other gays."
I don't know if his premise is correct, but I know I could always do it, and fairly accurately. It's only in recent years, living with a gay man and being in a mostly gay community, that I've lost a little of it. I presume from lack of practice, since I don't need it anymore, when almost everyone around me is gay.
Which suggests to me that it may function as a secondary survivor skill, where reliance upon it fosters development & improvement. Whereas little use brings atrophy of the skill, sort of a "use it or lose it" situation. But I dunno, just my idle speculation, to explain what I've experienced myself.