20:33 Jul 31, 2006 |
English to Portuguese translations [PRO] Tech/Engineering - Telecom(munications) / Satellite phone | |||||
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| Selected response from: Carlos Almeida Local time: 15:00 | ||||
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Summary of answers provided | ||||
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5 +1 | Antena Direccional tipo "patch" |
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1 | antena amplificadora direccional |
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antena amplificadora direccional Explanation: Normalmente, uma antena cujo poder de amplificação é ganho à custa da sua capacidade direccional. Este tipo de antena é muito usado actualmente no sistema GPS. |
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Antena Direccional tipo "patch" Explanation: olhei 180 paginas em Português e nenhuma tinha tradução para "Patch Antenna" The Patch Antenna Patch Antenna This is the antenna I made once. A patch antenna consists mainly of a square conductor mounted over a groundplane. The dimensions of the square are roughly 1/2 wavelength. The insulating space between the two planes may be air. The operating frequency of the GPS satellites is 1575 MHz. So half a wavelength is about 300000/1575/2 = 95 mm. Such an antenna 'looks' up, and is not very sensitive to the satellites on the horizon. But we are mainly interested in satellites above us. Some additional gain can be obtained by making the antenna not square, but shortening one side, and making the other side somewhat longer. In this way the antenna matches the circular polarisation of the satellites. Also the position of the feedpoint is important. It should present a 50 Ohm impedance. The exact calculations are much more complicated then those of a dipole. I found a sketch of such an antenna in an amateur radio magazine called QST (October 1995). http://home.iae.nl/users/plundahl/antenne/patchant.htm D-Link Portugal - Directional Indoor/Outdoor Patch Antenna. ANT24-1200 Antena Interior Direccional. ANT70-1000 Antena de banda dupla para interior/exterior de 8 dBi/10 dBi ... www.dlink.pt/?go=jN7uAYLx/oIJaWVUDb4aU93ygJVYKuJXStvhLPG3yV... |
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