If the satellite TV and radio need a dish or an antenna, why do not need GPS devices?
Just wondering why I do not need a GPS antenna. Simply connect the 12V power task and are looking for a group of satellites in space have not been necessary for an external antenna? Can anyone explain? THX!
There are two factors at play. The first is the type of satellite used, or more precisely the type of orbit. The GPS uses a orbiting satellite that allows satellites orbiting the earth. Satellite TV uses satellites, whose orbit is such that appear in a relatively static over Ecuador. The second is the frequency. GPS uses 1.2, 1.5 GHz, which allows the penetration of some buildings and windshields. Satellite TV with the use of microwaves for shortwave that require precise aim of the flat type antenna. In addition, a number of different satellites using the same frequencies, by so there is no way to distinguish between signals from different satellites, without a reflector dish to add more "profit" which is more easy to get a strong signal with an SNR lower. GPS uses Spread Spectrum frequencies.allotted to use to it, without interference between satellites, SS is not possible with satellite television because of the different services they carry. I'll tell you, like XM or Sirius satellite radio are not necessary a dish, but an outdoor antenna. XM uses geostationary satellites, such as television and Sirius a polar orbit. Both use frequencies around 2 GHz, and often require an external antenna, although usually not directional patch antenna type.
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