When using the AN/UPM-145 Radar Test Set, what step should you take if connecting to a radar with a max power over +50 decibel milliwatts (dBm)?

When connecting to a radar with a maximum power exceeding +50 decibel milliwatts (dBm) using the AN/UPM-145 Radar Test Set, the appropriate action is to use attenuators to reduce the overall input power. This is necessary because the test set can be damaged or provide inaccurate readings if it receives signals that are too strong.

Attenuators function by lowering the amplitude of the incoming signal to a safe level, ensuring that the radar test set operates within its optimal input range. This helps maintain the integrity of both the radar test set and the radar system being tested, allowing for accurate measurements without the risk of overloading the equipment.

In contrast, employing an amplifier would merely increase the power and risk further complications. Adjusting the RANGE selector would not address the fundamental issue of excessive input power. Therefore, the best practice in this situation is indeed to utilize attenuators.