Wireless gain and distance info

[JohanHammy]

I have been looking into 802.11a and 802.11b equipment. Are there any resources out there where I can find out what relationship watts output, gain, and distance have with each other. Obviously more watts\gain, more distance, but what kind of equations are there to figure out range based on wattage and gain information?

 

[Rilescat]

I don't have the answers, but I would also like to know!

 

[Shalmanese]

Well, for a uniform, non-directional transmitter, it should follow an inverse cube law. ie, you need 8 times the power to get twice as far.

 

[thornc]

Check the Calculations Page at YDI, they are a business company...
but they seem to know they're stuff, also check they FAQs....

Now say thanks...

 

[weepul]

lol! shalmanese's response reminds me so much of physics during the elctromagnetism chapters and even sound waves (decibels)

 

[Mark R]

Forgive me, but it's been a while since I did any physics - but why is it not an inverse square law?

For an isotropic emitter, surely the intensity of the field is inbevesely proportional to the surface area of the sphere around it (i.e. r^-2)

 

[Evadman]

My insane aerial.

That is the aerial I built for my truck. That post has a link to the site I got the idea from. Check it out. I think the aerial I built has a 18+ DB gain, but I have never tested it. If you go link surfing, someone built and tested a 802.11b link with 2 directional antennas ( like a dish ) that were able to connect to each other over a 28 mile ( that # is stuck in my head, but it has been a while, I may very well be wrong ) distance using only the outputed stock power from a linksys 802.11b gateway and card.

Be sure to turn on encription for any long hauls, or even short ones for that matter.

That link posted above is saying that I need a total of 63db to get 9 miles? That must be for full speed. I drop to 9k @ about 9 miles ( per mapquest ) so to get full throughput at 11 MBps I would need a 63DB gain?

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Oh, I see. those are for non-directional antennas. nevermind.
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