ARRL Technician Practice Exam 2026 – 400 Free Practice Questions to Pass the Exam

The term used to describe an amateur station that is transmitting and receiving on the same frequency is simplex communication. In this mode, both parties communicate using the same frequency, meaning that communication can only occur in one direction at a time. When one station is transmitting, the other must wait for a pause to respond, thus ensuring that only one signal is present on the frequency at any given moment.

In contrast, duplex communication involves the use of two different frequencies for simultaneous transmission and reception, allowing both parties to communicate at the same time without waiting for the other to finish. Half-duplex communication allows for sending and receiving on the same frequency, but not simultaneously—similarly to simplex, but the term typically refers to systems where switching is involved. Full-duplex communication refers to systems that can transmit and receive simultaneously without the need to switch frequencies.

Understanding these terms is crucial for effectively utilizing amateur radio operations, particularly in designing communication strategies for various situations and ensuring clear communication between stations.