Q: I am new to wireless. A tech came to install it in our hotel the other day and he seems to be a knob (for various reasons - one of them being he seems to think we will get a signal through 4 feet of concrete). Anyway we have the access points set up and placed the wireless laptop close to the access point. Nearby we have another PC on a LAN. The wired PC has no problem. However, the wireless cannot enter various sites. It has difficulty accessing about 85 percent of the sites we try. When it does access a site the speed is good and we can flip through pages quickly. Is this a firmware problem with the access point, or does he just not know how to configure it properly?
- Niko Santorini, Greece
Access points, to a degree, are pretty much turn-it-on-and-they-work. Since the problem appears to be somewhat random, we will need to approach this through a process of elimination.
Check your firmware
The first thing to look at is make sure the access point(s) are on the latest revision of firmware. Just because they were just unpacked doesn't take into account how long they were sitting on the shelf after manufacturing.
If this doesn't address the problem you can try changing antennas. If the access points were installed using the antennas provided by the manufacturer, there is definitely room for change. This may take a little experimentation. There are omnidirectional antennas that can provide more gain or effective transmitter power than the stock rubber antennas provided with most access points. Depending on how the access points were deployed, you may need to use directional antennas so you can focus or direct the coverage of the access points to where you need the service available.
The next thing to look at is the channels in use by the access points. Depending on how the access points were deployed and the number of floors in your building, an adjustment in the channels used by a given access point may also help the problem. The wireless card you're using should have some type of site survey/monitor function. If it doesn't, try the open-source product called Netstumbler. There are also commercial packages available that can help with this task. You need to see what access points are "visible" in any particular area of your hotel. If all the access points are set to the same channel, this could be part or most of the problem.
Think of it like this, if you have more than one FM radio station on the same frequency, you will sometimes hear one or the other or neither because of what is known as the "capture" effect, in which the strongest transmitter is heard. If they are equal, you may hear neither.
In Greece, you should be able to use Channels 1 through 13 (some other countries only have 1 to 11). I would recommend using Channels 1, 7 and 13. Change the use of the channels so no two access points are visible in the same area of your hotel using the same channel. This may be easier said than done - but a goal worth trying for.
Look for other radio sources
Also check to see what other wireless devices are in use in the hotel. Wireless phones running in the 2.4Ghz range can make an access point invisible to a wireless client. There may be other sources of interference that could be causing some of the problem. This will take time and some trial and error troubleshooting to identify and isolate.
Fix one access point first
It is possible you may have one or more access points that could be having a problem and/or are defective. If you can get things working well with one access point, you can use this as a base to compare with other access points.
Make notes of what you tried
Take good notes as you're going through the troubleshooting process, so as you find the source of the problem (and there could be more than one), you will have some idea of what you did to fix it.
Only change one thing
Try not to make more than one change at a time between tests so you can more quickly identify what change fixed the problem you are having.