To call the radio operator forward, what hand signal is used?

The correct choice is raising one hand to the ear, as this hand signal is widely recognized as a way to indicate the need for communication or to signal someone to come forward, particularly in tactical situations. This gesture effectively conveys the message to the radio operator that there is a need to engage in communication, without creating unnecessary noise or distraction that could compromise security or draw attention.

Using other signals or shouting may not be appropriate in a tactical environment, where maintaining stealth and silence is crucial to ensure safety and operational effectiveness. The hand signal to the ear is both discreet and universally understood among communications personnel, making it the most effective way to call the radio operator forward in the context of fire team operations.