In the Primary Surveillance Radar (PSR), if one transmitter amplifier module fails or is in standby, the remaining seven amplifier modules will provide a minimum of 14kW peak power. This is enough power to cover how many nautical miles (nm)?

In the Primary Surveillance Radar (PSR), if one transmitter amplifier module fails or is in standby, the remaining seven amplifier modules will provide a minimum of 14kW peak power. This is enough power to cover how many nautical miles (nm)?

• A. 60 nm
• B. 50 nm
• C. 70 nm
• D. 40 nm

Answer: (B)

The amount of coverage a primary surveillance radar can provide is set by the transmitted peak power and the sensitivity of the receiver, with the radar range governed by the radar range equation. In simple terms, increasing transmit power lets the radar detect weaker echoes at greater distances, but the relationship is not linear—the detectable range grows with the power to the one-fourth power, so more power yields diminishing returns. In this scenario, even with one transmitter amplifier module failed or in standby, the seven remaining modules still supply at least 14 kW of peak power. That amount meets the system’s fault-condition specification for minimum coverage. The PSR is designed to maintain a defined surveillance range under these fault conditions, and that defined range corresponds to about 50 nautical miles. Distances like 60 or 70 nm would require more power than 14 kW to achieve, while 40 nm would be below the specified minimum under this fault state. So the correct coverage is 50 nautical miles.

The amount of coverage a primary surveillance radar can provide is set by the transmitted peak power and the sensitivity of the receiver, with the radar range governed by the radar range equation. In simple terms, increasing transmit power lets the radar detect weaker echoes at greater distances, but the relationship is not linear—the detectable range grows with the power to the one-fourth power, so more power yields diminishing returns.

In this scenario, even with one transmitter amplifier module failed or in standby, the seven remaining modules still supply at least 14 kW of peak power. That amount meets the system’s fault-condition specification for minimum coverage. The PSR is designed to maintain a defined surveillance range under these fault conditions, and that defined range corresponds to about 50 nautical miles. Distances like 60 or 70 nm would require more power than 14 kW to achieve, while 40 nm would be below the specified minimum under this fault state. So the correct coverage is 50 nautical miles.