Why were early World War I radios used mainly as backup systems?

During World War I, early radio technology was primarily relegated to a backup or auxiliary role due to several significant technical and operational limitations:

• Unreliability: Early wireless systems were inherently unreliable for consistent tactical communication.12
• Ease of Interception: Because radio signals were broadcast, they were highly susceptible to enemy interception, necessitating the use of complex cryptography or encoding, which slowed down communication.1
• Equipment Constraints: Initial radio sets were too heavy and bulky for trench warfare and required large, highly visible aerials that made them impractical for frontline use.1
• Preference for Wire: Belligerents relied heavily on an extensive grid of buried telephone and telegraph lines, which were considered the primary means of communication. Radio was reserved for emergency use specifically when these wire lines were severed by intense artillery fire.12

While radio technology improved throughout the war, it remained secondary to wire systems until further developments between the world wars enabled the portable, reliable equipment that eventually revolutionized command in World War II.13