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**Unformatted text preview: **transmitting antennas eective area is equal to its physical area. Then the on-axis (max) gain can be written in terms of its radius as: G 1 max = 4 A 1 eff 2 = 4 2 R 2 1 2 Now collecting the terms and solving for the radius of the transmitting antenna: R 1 = . 7 r 2 2 A 2 eff 1 / 2 = . 7 (1000 10 3 ) 2 (0 . 01) 2 7 . 07 1 / 2 = 1 . 78 10 3 m 2 So is this a practical antenna size? This is almost 12 times the size of the main reector at the Arecibo Observatory, which is the biggest in the world (305 m in diameter)! So, requiring that 70% of the power transmitted be received is not practical! (Not even close!) A requirement of 1% would still need a dish bigger than Arecibos. 2. Items to review? 3. Ask for questions. CORNELL UNIVERSITY c WES SWARTZ (09/11/7) 141...

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