Final answer:
The first step in troubleshooting a UHF LOS (Line-of-Sight) fault is to inspect the antenna.
Step-by-step explanation:
The first step in troubleshooting a UHF LOS (Line-of-Sight) fault is to inspect the antenna. When encountering a fault in the UHF LOS, it is important to check whether the antenna is properly connected, positioned correctly, and free from any physical damage or interference.
By inspecting the antenna, you can identify any visible issues or misalignments that may be causing the fault. If the antenna appears to be in good condition, you can then proceed to check other components such as the power supply, frequency, and modulation.