anoclon
join:2004-10-12
Guatemala
| reply to superdog
Re: Remember "3 town wisp setup" ?
That´s what I don´t understand!! Maybe you can explain me why if I have a good signal strength and a good signal quality, and with this I mean a good Link, why is it matter the kind of radio I use? What´s the important? What if a 100dBi grid antenna exist? wouldn´t be enough to point and face 2 of this 100dbi antennas against each other in a 4 mile link with a D-Link radio? what´s the difference with the smartbridges or any other brand radio? Why the throughput increases just because you change the radio?Please, I really wanna know why? could anybody of you of this forum tell me? |
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IntraLink
Premium,MVM
join:2002-08-14
Utah Valley
| Throughput is a factor of many things.
If you take any combination of these radios on the bench and test throughput you could get a good idea of what they do in the field IN AN IDEAL RF ENVIRONMENT.
In other words, you are right. If you take a good link at 5' and do the calculations to get the right antenna for the proper signal strenght you can effectively get the same link. Not taking into account the environment.
That is what fade margin is for. If you over-engineer the link a bit and get 10db of fade margin for a typical 802.11b link you should be good speed wise.
The more speed the greater the sensitivity needs and usually the more fade margin you want. That's why it's not a linear slope to get higher speeds. More like an exponential curve. |
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superdog
I Need A Drink
Premium,MVM
join:2001-07-13
Lebanon, PA
| reply to anoclon
said by anoclon  :That´s what I don´t understand!! Maybe you can explain me why if I have a good signal strength and a good signal quality, and with this I mean a good Link, why is it matter the kind of radio I use? What´s the important? What if a 100dBi grid antenna exist? wouldn´t be enough to point and face 2 of this 100dbi antennas against each other in a 4 mile link with a D-Link radio? Well, To start with, power is not always the answer, and I personally would rather have two 30Mw radios talking at 5 miles with 2 24dBi grids and a really high receive sensitivity(Which I have done without a problem-2Mb thruput in a high noise environment), than I would 2 radios at 200Mw and low gain antennas, as the amount of noise they will pick up is crazy at the higher power level. It really is all about engineering?. The only reason that a lot of OEM gear makers have come out with 500mW Ap's is because we will always have a mindset that bigger is better, and in the radio world, it is just not true!. It has been said here over and over again that antenna gain is preferred over radio gain any day of the week. When I read posts that say they can't get a link with a 15dBi omni and a 1 watt amp with a 200Mw client radio 3 miles away, I almost lose my mind!. I am not yelling at anyone, I am just trying to make a point, and the point is this:
Use the best radio that You can, with the lowest power possible for a stable link. If You can get away with a 30Mw radio and a 26dBi dish, then do it!. It will work 10 times better than a 200Mw radio with a poor receive sensitivity and a 19dBi grid any day of the week.:)
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