I think my Gaydar is broken.

If you are someone other than a straight female living in Sydney, you may require a translation. Gaydar: the technical term used to describe the way in which heterosexual women discern whether a man is homosexual. Also known by its more colloquial name: Queen Meter.
—Mia Freedman, "Sydney unzipped," Sun Herald (Sydney), August 18, 2002

The pick-up area is confined to the west part of the heath, a clearly defined dell cut off from the rest by a main road. Within it, formal, if perfunctory, courtship rituals were being performed among the bare trees. Men meandered with studied slowness along the paths, waiting for eye contact from passers-by. When their ''gaydar'' told them that an assignation was on, they went up short, well-trodden tracks, strewn with foil condom wrappers, which led straight into the undergrowth.
—Nick Cohen, "Out in the undergrowth," The Independent (London), March 15, 1992