rjanakan
03-17-2004, 10:02 PM
Hi,
I'd really appreciate if anyone let me know the details of range supported by 802.11 b/a/g if the AP is used in the top of the building in a city environment......May be like a Public WLAN.....
Would appreciate if anyone send me the link which talks abt installing AP in public places for WLAN under 802.11 b/a/g.....
Is it possible to connect external antenna to an AP to extend the coverage in all those 3 technologies...and if it is possible, wat is the max. diameter of the antenna that could be connected or wat is the maximum coverage that could be provided by that AP.....
Thx in advance....
Regds,
Janakan Rajendran
Welcome to the forum, will try to answer your questions. But it is somewhat dependent on each individual circumstance. First, it is not a good idea to try and offer multiple bands in one location, unless you use individual devices for each band. If this is an outdoor project, it is important to know that 11b delivers the most power. Where 11a and11g use a different modulation technique and it usually has about half of the output. That is why for right now, you see long distance links using 11b for the most part. You have another issue, if you place the node on top of a building, depending on the antenna vertical coverage angle, you may not get a link signal for many meters from the node location. This link will help you understand some of the calculations and numbers that go into determining if the link will work and what is required for power and what antenna gain will be needed. It also talks about the downtilt issue and what will be needed to cover a specific area when the antenna is at certain heights.
http://www.ydi.com/calculation/index.php
As for how to setup a public hotspot, here is one link.
http://www.wi-fiplanet.com/news/article.php/1184811
If you google, you will find quite a lot of information on the subject. That might be best as I am not sure what you are looking for in that regard. Also I am not sure where in NY you live, but there is a very active User Group in NYC and they have a good mailing list style forum.
http://www.nycwireless.net/
As for your last question, yes it is possible to add external antennas to most AP's. It will depend on the connector on the device. There are many available external antennas for 11b and 11g. But 11a is not really supposed to be a long distance band and in most cases it is used only where many AP's are in close proximity and you can use all the different channels available without causing interference.
Your question about diameter is confusing, maybe if you explain that differently. Also the coverage area is determined by many factors, and it would be hard to generalize any kind of statement about what is considered the maximum coverage. I feel the vendors that advertise that sort of number are doing a dis-service to the public as the numbers do not mean anything.