I’m interested in maximum wi-fi speed at distance of 12 Km. We have limit at summary power of antenna and card - 1 W. Please, recommend some dish antennas with needed dBi. Wifi cards r52h have ability to regulate power in them, how much power we have to set them to avoid exceeding of summary power of 1 W. Frequency from 5,4 to 5,7.
P.S.
In our country, state structures of regulation radio frequency, count summary power of cards and amplification of antenna.For example, at frequency 5,4 we have maximum summary power of 1 W. Is this right by european standards or not?
I don’t know what speed do you want to reach, and wich signal sensitivity has your radio.
To be practical, with radio I use, I need to reach a -70 dB signal for good results.
(i’m not sure about use of dB, dBi, dBM but i’m sure to explain the concept well )
So you have to fight to reduce -128.653 dB attenuation to reach your target receiver sensitivity keeping in mind the 30 dBm EIRP ETSI power regulations (30 dBm equivalent to 1 Watt)
You could do it, by antenna gain or by TX radio power.
Anyway, on long distance point to point link is preferrable to use antenna gain.
An High gain antenna is strictly directional and less subject to noise and interference (but is harder to direct )
On power vs air loss balance you could calculate TX and RX antenna while you can count only on transmitting power.
Supposing to choose two 28 dB Antenna, you could set transmit power to 2dBm to be compliant to regulations.
(http://www.ubnt.com/support/mwtodbm.php)
link balance = free air loss + tx power + tx antenna gain + tx cable loss + rx antenna gain + rx cable loss
assuming cable loss to 0:
-128,653 + 2 + 28 - 0 + 28 -0 = -70,653 dB
We should expect a good link according to radio receiver sensitivity at desired speed.
Anyway… Antennas direction mistakes, radio interference, Water waves reflections, fresnell effect obstructions and finally “aliens factors” could produce a result different from expected.
Good Luck
p.s. a 30 dB Antenna is on limit of ETSI regulations.
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