Arecibo has two large radar systems suitable for power beaming demonstrations. A third system can be used for ionospheric heating experiments but is not really suitable for power transmission. These radars were used to beam power into the upper atmosphere (but not through it) in 1977 during the Ionosphere / Microwave Beam Interaction Study. [8] The first of these radars, which transmits at 430 MHz, has a peak power of about 2 MW. a 6% duly cycle, and an antenna with 61.5 db of gain. The second radar, which may be of most interest for power beaming, transmits at a frequency of 2.38 GHz with a power level of 400 kW and a continuous duty cycle. It’s antenna has a gain of 71 db. The 2.38 GHz radar at Arecibo is probably the most powerful continuous wave system on Earth at the present time. [7] The facility itself centers around a dish 305 meters in diameter, the largest in the world. Due to its large size, and the fact that it takes up an entire small valley as shown in Figure 1, the dish itself cannot be moved. Pointing is achieved by moving the transmitting antenna which hangs over the dish suspended by a network of cables. This imposes two effective limitations on the use of the facility. The first of these is that it can point at most 20° from zenith. This is a fairly restrictive limit on the area of the sky which can be covered, but it should be noted that Arecibo itself lies at a latitude of 18.3°, and so some equatorial orbits could be covered, though not GEO as will be shown later. The major problem with the facility is that it cannot track quickly; it can follow planets but not satellites. The transmitters focus at infinity only, but this should not be a significant problem.
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