quote:Originally posted by John Davis: Regarding Gain antennas.
An antenna with higher gain can transmit farther
All other factors being equal it can also RECEIVE farther. The gain is "Bi-directional"
One other factor worth mentioning, is that with increased gain also comes narrower vertical beamwidth. A high gain antenna may increase distance, but it may also jump right over someone close in. A 2db antenna will have a vertical beamwidth of 35-40deg, while a 15db antenna will only have about 10-12deg of vertical beamwidth. Therefore someone close in will not be in the optimum path. Antenna height also is a factor. The optimum height for a wifi network is 20-25 feet. If directional antennas are used, they should have about 1-2 degrees of down tilt.
OK... so if you assume an omnidirectional antenna truly broadcasts in all directions (i.e. a sphere), which I assume it doesn't REALLY do, but humor me... then a higher-gain antenna broadcasts out in a "flattened" sphere? More like a donut shape?
-------------------- - John '05 Newmar Mountain Aire DP 4304 F1/D2 v3.7.6/DW7000SM/89w/1170V/Apple Airport Extreme N/Secure Wireless Apple 17" MacBook Pro & Dual Quad Core Mac Pro (OS X 10.7.x) Posts: 146 | Registered: Mar 2005
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quote:Originally posted by John Davis: Regarding Gain antennas.
An antenna with higher gain can transmit farther
All other factors being equal it can also RECEIVE farther. The gain is "Bi-directional"
One other factor worth mentioning, is that with increased gain also comes narrower vertical beamwidth. A high gain antenna may increase distance, but it may also jump right over someone close in. A 2db antenna will have a vertical beamwidth of 35-40deg, while a 15db antenna will only have about 10-12deg of vertical beamwidth. Therefore someone close in will not be in the optimum path. Antenna height also is a factor. The optimum height for a wifi network is 20-25 feet. If directional antennas are used, they should have about 1-2 degrees of down tilt.
OK... so if you assume an omnidirectional antenna truly broadcasts in all directions (i.e. a sphere), which I assume it doesn't REALLY do, but humor me... then a higher-gain antenna broadcasts out in a "flattened" sphere? More like a donut shape?
It would be more like a flattened horizontal figure eight. The higher the gain, the flatter it is.
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