Wireless network - unstable

I am running a wireless network of 8 Desktop computers in 5 adjacent offices at the same building on the same floor. The network is very unstable. Some coputers show low signal strenght. How can I boost the signal strength to all the pc's

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Have you tried re-positioning the Wireless Access point/Router???
A lot of things can effect the performance of wireless networks and you may find that moving the box around a trying different places may increase performance.

Another thing would be to try a different aerial,


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One big issue is wather. 'Cause the resonance freqency of wather is 2,4GHz wich is the same freq. on witch wifi works. So any time you palse a AP you have to be shure there are no watherlines, showers, or the Dolphin in the way.
Unstable signal by wifi means something comes sometimes in the way, so always check the physical layer! (once we had the problem too 'cause they plant a crane to the way, and it worked only if the cran was in one possition :) )

Sam PanwarSr. Server AdministratorCommented:
That's going to depend on the actual bit-rate that the your wireless network adapters have negotiated with the access point.  If they've already managed to negotiate an 11 megabit/second link speed, and if the
transfers are working reliably, then an increase in signal strength might not result in any increase in throughput.  Your adapters may already be handling the data as fast as the airwaves allow.

It couldn't hurt to try, of course, but since the wireless connections are already being listed at a very-good-to-excellent quality I suspect that you may not see a real increase.

There's another, less-conventional approach you might consider trying if you're up for some significant fiddling around.  You could try switching the wireless systems over to use "point to point" or "ad hoc"
networking mode, rather than "infrastructure" mode - I think the setup and drivers may support this.

Background:  in its most common (infrastructure) mode, all of the RF traffic travels between client systems (e.g. wireless connection machines or laptop PCs) and an access point.  Traffic does not go directly between clients, even if both are located quite close to another and can "see" each other better than they "see" the access point.  This means that when you do a Home Media Option transfer, every bit of the video data is going over the airwaves twice - once from the sending wireless router to the access point, and a second time from the access point to the receiving wireless router.  This cuts your theoretical-maximum transfer rate in half, compared to what a point-to-point transfer would allow, and it's one of the reasons that wireless HMO transfers are usually slower than wired-Ethernet transfers.

An alternative is to use "ad hoc" networking mode, in which all of the clients operate as peers and "speak" together directly.  This cuts the number of packets sent over the air in half (since each is sent once,
rather than twice) and can increase your bandwidth.  It's doesn't come for free, though, since it's not as easy to hook up to the Internet (most commercial access points operate _only_ in infrastructure-mode
and cannot be configure to operate in ad-hoc mode), and your bandwidth may actually drop if the two wifi systems are far enough away from one another that they can't negotiate an 11-megabit connection.

A third approach is to switch to a wired network.  You can probably increase transfer performance by some amount even if you put only one of the wifi systems on the wired network (e.g. whichever is closest to
a hub or switch) and leave the other on the wireless, as this will eliminate one of the two over-the-air hops for each packet.

A fourth approach is to install a second access point, operating on a different channel, and make sure that the two wifi systems are talking to different access points.  This should allow for some amount of
overlap in the packet traffic, since one TiVo will be able to send a packet to its access point while the other access point is relaying the previous packet to the other TiVo.
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According to your situation, it seems that you only have one Access point which you are using for all the system accress your offices across walls or cabins.

Signal Range Parameters described by manufacturer are for some specific standard and you won't get described bandwidth and Signal Range under our surroundings.

These type of obstacles low down the signal Amplitude and hence it's not available to some machines all the time.

Clients connected via wireless are connected on a continual basis, similar to a standard ethernet connection.

However, the wireless signal is much more likely to be interupted due to noise or poor signal strength than an ethernet cable is likely to be temporarily disconnected from the back of a PC.

As such if your application doesn't handle a disconnect/reconnect situation gracefully (most don't) then unless your signal strength at the client is very good you should expect the connection to get dropped occasionally.

My personal experience from a 24x7 production environment is that even with excellent signal strength, occasional signal interferance means you should expect the connection to be dropped anywhere from once per day to once per week. I have not yet personally  seen a wireless connection be maintained without a disconnect/reconnect for longer than a week.

Solution :-

To overcome the problem you should do these steps.

  1. Relocate your Access Points at Different Place.
  2. Increase the no of Access Points. (Place Two / Three Access Points at different locations in the office)
  3. Search for any electronic equipment that runs on the same frequency of your NIC. (Try Switching-OFF unwanted equipments for a while).

Wireless NIC Details :- http://www.ciscopress.com/articles/article.asp?p=344242&rl=1

Improving Wireless Range: Overview

Everyone can improve wireless range and throughput by:

    * Choosing the Best Locations
    * Tuning Your Equipment
    * Choosing the Right Equipment to Upgrade
    * Testing your improvements. Testing Wireless Range explains the options.

Better equipment — such as RangeMax — can provide a quick fix. But the best approach is to work on all four items. For information specific to RangeMax equipment, see Improving Range with RangeMax

Wireless and Antenna Terms

Wireless routers, access points, and adapters send and receive radio wave signals through antennas. The antenna is hidden inside adapters, but on routers and access points there's a visible antenna. Radio waves can be focussed like a lightbulb. And like a light, some materials reduce or stop radio waves. While light focused from several lights is brighter and makes it easier to see, several antennas in the same area cause interference — the radio signals will be muddy and confused.

Your goals in optimizing power are:

    * Avoid obstacles.
    * Avoid interference.
    * Increase signal strength. Power affects how far an antenna radiates.
    * Use the equipment in places it's most powerful and most sensitive.

Antennas don't radiate equally in every direction. Just as the base of a lightbulb blocks light, and just as a light can be focussed by a reflector, so an antenna signal may be blocked and focused. Since people cannot see radio waves, you'll rely on testing and trial-and-error to get an idea of where antennas "shine" most brightly. An adapter's antenna is important, but the most powerful and sensitive antennas are on routers, access points, and detachable external antennas.

The focus of an antenna is either omni-directional antenna or directional. "Omnis" are used in most home products, they radiate horizontally all around, but are weaker upward or downward. When visible, these antennas are usually a rod a few inches long. A directional antenna radiates strongly in a limited direction. It is a flat panel or a dish. These are used for point-to-point transmissions (where two antennas are focused directly at each another). These need a line of sight between them, and preferably a large open space around the main beam.

When you are near antennas you'll still get a signal, even if you are out of the direction of its strongest signals. But when further away, you have to be in the direction the beam is the most powerful and unobstructed to receive it.

One final concept before you go to the above links is interference. Interference is a signal — one you don't want — at the same frequency as the one you're using. Interference comes from devices such as microwave ovens, cell phones, 2.4 GHz cordless phones, and copy machines. Interference is also caused when your own wireless signals are bounced off reflecting objects. Objects may partly or completely absorb signals, reflect them, bend them, or let them pass right through. Metal and water (including the water in people!) absorb or reflect signals. Air, wood, and glass tend to let signals pass with weakening. And when outdoors, plants and the weather may cause interference.

Wireless Network Troubleshooting in Detail  :- http://kbserver.netgear.com/kb_web_files/n101179.asp
First thing I would do is verify all the computers are using the same wireless cards.  There can be issues with some wireless cards not picking up as well as others, etc.  
obliv2k3Business and IT Systems EngineerCommented:
Check all computers are using Windows XP SP2 (If your using Windows) as this fixes some issues with the way windows handles wireless traffic.
Second, If you have a large distance between the AP and firthest client invest in a more porweful AP, 3 arials on the AP will enhance performance.
Third, ensure all wireless network cards are rated to the same standard and that they can all connect at the same speed, IE if your router is 125mb* and all bar one client can connect at the same speed then the router will speed match with the slowest client. IE using one 802.11b device in a 802.11g dominated network.

Check for alternate networks running close to your channel, try switching to something clear from others ie if your using channel 8 and another is using 7 then move to channel 3.

Check for other wireless traffic that can inferfeer such as Radios and TVs.

*Denotes an enhanced standard with therotical speed
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