Onmi's are generaly for saturating an area, if your looking at distance, look at Flatpannel of grid antenna, you will get between 1-10 km with them, however, the following play a huge role.
1. Dbi - the stronger this is the more clear your signal will be. It does not increase distance.
2. Milliwatt - now this is where you get your distance from. normal AP's are 100mw as per SA regulation however you can buy 200mw at the same price from some manafactures as well as ampliphers whcih will go up to 1000 mw.
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