Every Tuesday and Friday morning in a dining area tucked behind Dunkin’ Donuts in the Pentagon’s main food court, a gay coffee group meets to talk, do a little business and tell a few jokes. Started quietly by a handful of Air Force officers in 2005, the gathering has grown to as many as 40 people since the repeal of the “don’t ask, don’t tell” policy last September. The crowd is a testament to the openness in the military now that gay, lesbian and bisexual service members no longer have to keep their sexual orientation secret or face discharge — and also to how such gatherings are still needed. “Honestly, it’s a support group,” said Sean M. Hackbarth, the Air Force lieutenant colonel, now retired, who started the gatherings of uniformed military and civilian defense workers and who still drops by for coffee when he’s at the Pentagon. “It’s a way of making people less afraid. Even with repeal, there’s still that trepidation of being out in the military.” It has been exactly a year since “Don’t Ask, Don’t Tell” was repealed, and by most measures the change has been a success. Gay service members say they feel relief they no longer have to live secret lives. Pentagon officials say that recruiting, retention and overall morale have not been affected. None of the dire predictions of opponents, including warnings of a mass exodus of active duty troops, have occurred.