Which of the following may transmit encrypted messages?
The correct answer is B: Telecommand signals from a space telecommand station. Which of the following may transmit encrypted messages is telecommand signals from a space telecommand station. Only space telecommand signals may be encrypted; other amateur communications cannot be encrypted. For amateur radio operators, this is important for satellite operation. Understanding this helps ensure legal operation.
Exam Tip
Encrypted messages allowed = telecommand signals from space telecommand station. Think 'E'ncryption = 'E'xclusively for 'S'pace 'T'elecommand. Only space telecommand signals may be encrypted; other amateur communications cannot be encrypted. Not terrestrial telecommand, not repeater audio, not mesh network - just space telecommand.
Memory Aid
"Encrypted messages allowed = telecommand signals from space telecommand station. Think 'E'ncryption = 'E'xclusively for 'S'pace. Only space telecommand signals may be encrypted; other amateur communications cannot be encrypted. Important for satellite operation."
Real-World Application
Encrypted messages: Only telecommand signals from a space telecommand station may be encrypted. For example, commands sent to a satellite may be encrypted to prevent unauthorized control. All other amateur communications (repeater audio, mesh networks, terrestrial telecommand) cannot be encrypted. This is the only exception - space telecommand signals may be encrypted.
FCC Part 97.113Key Concepts
Why Other Options Are Wrong
Option A: Incorrect. Telecommand signals to terrestrial repeaters cannot be encrypted - only space telecommand signals may be encrypted. Terrestrial telecommand isn't allowed.
Option C: Incorrect. Auxiliary relay links carrying repeater audio cannot be encrypted - amateur communications cannot be encrypted except space telecommand. Repeater audio isn't allowed.
Option D: Incorrect. Mesh network backbone nodes cannot be encrypted - amateur communications cannot be encrypted except space telecommand. Mesh network isn't allowed.
题目解析
The correct answer is B: Telecommand signals from a space telecommand station. Which of the following may transmit encrypted messages is telecommand signals from a space telecommand station. Only space telecommand signals may be encrypted; other amateur communications cannot be encrypted. For amateur radio operators, this is important for satellite operation. Understanding this helps ensure legal operation.
考试技巧
Encrypted messages allowed = telecommand signals from space telecommand station. Think 'E'ncryption = 'E'xclusively for 'S'pace 'T'elecommand. Only space telecommand signals may be encrypted; other amateur communications cannot be encrypted. Not terrestrial telecommand, not repeater audio, not mesh network - just space telecommand.
记忆口诀
Encrypted messages allowed = telecommand signals from space telecommand station. Think 'E'ncryption = 'E'xclusively for 'S'pace. Only space telecommand signals may be encrypted; other amateur communications cannot be encrypted. Important for satellite operation.
实际应用示例
Encrypted messages: Only telecommand signals from a space telecommand station may be encrypted. For example, commands sent to a satellite may be encrypted to prevent unauthorized control. All other amateur communications (repeater audio, mesh networks, terrestrial telecommand) cannot be encrypted. This is the only exception - space telecommand signals may be encrypted.
错误选项分析
Option A: Incorrect. Telecommand signals to terrestrial repeaters cannot be encrypted - only space telecommand signals may be encrypted. Terrestrial telecommand isn't allowed. Option C: Incorrect. Auxiliary relay links carrying repeater audio cannot be encrypted - amateur communications cannot be encrypted except space telecommand. Repeater audio isn't allowed. Option D: Incorrect. Mesh network backbone nodes cannot be encrypted - amateur communications cannot be encrypted except space telecommand. Mesh network isn't allowed.
知识点
Encrypted messages, Telecommand signals, Space telecommand station, Encryption
Verified Content
Question from official FCC Extra Class question pool. Explanation reviewed by licensed amateur radio operators.