What term describes more than one radio user transmitting at the same time?

The term that accurately describes more than one radio user transmitting at the same time is "simultaneous transmission." This concept refers to instances where multiple users attempt to send their communications over the same frequency or channel concurrently. When simultaneous transmissions occur, it can lead to overlapping signals, causing confusion and interference, which can hinder effective communication.

Covering, technical interference, and multi-channel usage do not appropriately define the situation where multiple users are transmitting simultaneously. Covering typically refers to taking over communication duties or providing support. Technical interference concerns the disruption of signals due to electronic or physical barriers, rather than merely the act of multiple transmissions. Multi-channel usage involves utilizing more than one channel for communications, which may or may not include simultaneous transmissions.

Understanding the correct terminology helps in comprehending the challenges associated with radio communications and the importance of managing frequencies to prevent transmission conflicts.