Player on the court yelling after every set. Whats the call?

[Homer]

Virginiaref has got it just about right. The conduct is fairly encompassed as unsportsmanlike conduct within 12-2-8c "questioning or trying to influence officials' decisions".

The situation is similar to 12.2.7 in the casebook where a team is shouting "touch" each time they hit the ball out of bounds. The casebook deems that conduct worthy of a warning and then a card for repetitions.

The casebook suggests a verbal no-card warning (reminder) to the captain and then a yellow card for a subsequent offense.

Going immediately to a red card after the verbal warning might be a bit more severe than I would be inclined to go but the official is certainly within his/her authority to administer an immediate red card - a intentional repeated offense after a clear warning could certainly be deemed a "serious offense" where the "situation warrants" issuing an immediate red card without first giving a yellow.

However, whistling the ball dead to administer the card is NOT correct. The rulebook clearly specifies that cards shall be administered "at the first dead ball". The play should continue and the penalty card administered after the rally is ended.