hi, i have a question about wireless networking since the manufacturers always talk about high gain antennas they never seem to mention about the distance it's gonna cover like if they say as an example if u have this router/ap and if u attach that antenna to it u can cover upto 5 km/miles .. like that(under normal circumstances) which will be very helpful for ppl like (i dont know anyone else exist like me or not..) anyway .. is that too much to ask... pls comment
------------------------------------------------------------------------ View this thread:
I'll resist the temptation to answer your question with one long sentence.
It's fairly easy to calculate the range of given system if you know the parameters. See example at:
However, let's make it even easier. Let's pretent you have a generic access point with the stock 2dBi rubber ducky antenna, and a generic laptop, with the stock 0dBi internal antenna. You take a walk with the laptop and find that you can surf the internet reliably to about
20 meters range.
You then think...... perhaps if I install an aftermarket antenna on the access point. How far will I get?
Well, that's really easy. Each 6dB of gain is double the range. 12dB is 4 times. 18dB is 8 times the range. 24dB is 16 times the range. So, a 24dBi dish antenna will yield identical speed and thruput of:
Range increase = 10^(dB/20) = 10^(19/20) = 10^0.95 = 8.9 times the range or 178 meters.
However, that might set you thinking that perhaps a bigger antenna might be useful on the laptop. The same logic applies. I'm lazy so I'll just attach another 24dBi dish antenna with the same lossy coax cable. However, instead of a 2dBi rubber ducky on the access point, we're blessed with a 0dBi ceramic antenna with a rather lossy piece of tiny coax. I'll be generous and give it 0dBi gain.
Range increase = 10^(dB/20) = 10^(21/20) = 10^1.05 = 11 times the range. So, your 178 meters range is now: 178 * 11 = 1,958 meters range. Is that far enough?
Unfortunately, this is for ideal conditions, with no interference, no Fresnel Zone issues, perfectly aligned antennas, and perfect line of sight. In the city, it's almost impossible to find a 2000 meter path with such conditions. Therefore, you may not be able to go that far.
Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.