What is the antenna rule in volleyball?

Full Explanation

Per FIVB Rule 2.4, the antenna is a flexible rod, 1.80 m long and 10 mm in diameter, fastened at the outer edge of each side band of the net, with its top 80 cm extending above the net. The antennae are considered part of the net and laterally delimit the crossing space, so the ball must cross the net entirely between the two antennae and their imaginary extensions (FIVB Rule 10.1.1). Per FIVB Rules 8.4.3 and 8.4.4, the ball is out if it touches an antenna or crosses the net plane partly or totally outside the crossing space. One exception: a team's first hit that crosses outside the antenna toward the opponent's free zone may be played back under FIVB Rule 10.1.2. A player who touches the antenna during the action of playing the ball commits a fault (FIVB Rule 11.4.4). Either way, the penalty is a point awarded to the opponent. Line judges signal balls touching the antenna or crossing outside it (FIVB Rule 29.2.1), and the antennas help them judge whether a ball crossing the net is in or out. The same rule applies under USAV, NFHS, and NCAA rules.

Rulesets covered: FIVB/USAV/NFHS/NCAA  |  Rule Reference: FIVB Rule 2.4; FIVB Rule 8.4.3; FIVB Rule 8.4.4; FIVB Rule 10.1; FIVB Rule 11.4.4