Solutions Instruments sending sound up in urgent message has 4 entries with similar clues

• 5-letter words
• ravenBird used for sending messages on "House of the Dragon"
• 7-letter words
• tweeterPerson sending a message of fewer than 140 characters
• 9-letter words
• postcardsThey are the cheapest way of sending messages through P&T
• cablegramUrgent message