A blind-mate connector (10, 20, 100) has a barrel (11, 21, 105), a base (12, 22, 110) at the back end of the barrel, an insulator (17, 27) mounted in the base, and a center conductor (15, 25) extending from near the front end of the barrel, through the insulator, and extending beyond the back end of the base, with the center conductor being held by the insulator. One type has sidewalls (13, 23) extending rearwardly from the back end of the base, and alignment notches (14, 24) on the sidewalls, the alignment notches extending only partially from the back ends of the sidewalls toward the base. Another type has alignment tabs (125) extending rearwardly from the back end, and sidewalls (130) extending rearwardly from the back end of the base, the first tab being above the first sidewall.