Related Clues:

• Short whistle blower
• Ham, for one
• Sports official
• Donna Summer's 'On the --'
• Foul caller
• Field judge
• 'Huzzah!,' e.g.
• One calling the shots?
• One who might count you out
• Maker of many calls
• Dashboard device
• Communication device
• Herald
• Short official?
• Some waves