What should be done before giving a long message?

Before giving a long message, it is essential to advise the pilot when they are ready to copy. This ensures that the pilot has the appropriate attention and resources to accurately receive and record the information being conveyed. Long messages can be complex and require focused listening; notifying the pilot ensures that they are prepared to receive the necessary details without any distractions or interruptions, minimizing the risk of miscommunication.

While notifying all parties involved, ensuring equipment functionality, and confirming the message length may be important in certain contexts, they do not specifically address the immediate need for the pilot's readiness to receive a long message, which is crucial for effective communication in a non-radar environment.