What is the EIRP listed for the Arecibo transmitter?

What is the EIRP listed for the Arecibo transmitter?

• A. 5 trillion watts
• B. 50 trillion watts
• C. 20 trillion watts
• D. 200 trillion watts

Answer: (C)

EIRP is the effective radiated power in the direction the antenna is pointing, calculated by multiplying the transmitter power by the antenna’s gain in that direction. For Arecibo, the transmitter delivers about one megawatt (roughly 10^6 W) of RF power into a massive 305-meter dish. The dish provides a very high gain at its operating frequency—on the order of tens of millions (about 2 × 10^7). Multiplying these together gives roughly 2 × 10^13 watts, i.e., about 20 trillion watts. So the EIRP listed for the Arecibo transmitter is around 20 trillion watts. The exact figure can vary slightly with frequency and efficiency, but this is the typical value that matches the system’s power and aperture.

EIRP is the effective radiated power in the direction the antenna is pointing, calculated by multiplying the transmitter power by the antenna’s gain in that direction. For Arecibo, the transmitter delivers about one megawatt (roughly 10^6 W) of RF power into a massive 305-meter dish. The dish provides a very high gain at its operating frequency—on the order of tens of millions (about 2 × 10^7). Multiplying these together gives roughly 2 × 10^13 watts, i.e., about 20 trillion watts. So the EIRP listed for the Arecibo transmitter is around 20 trillion watts. The exact figure can vary slightly with frequency and efficiency, but this is the typical value that matches the system’s power and aperture.