# Solved: WIFI speed fluctuation



## pcfeer (May 1, 2007)

Hi, my laptops wifi speed drops from 54Mbps down to 1Mbps which is often causing me to disconnect from web application etc I am currently using a usb wifi dongle and the speed does not drop from 54Mbps which has made me believe the problem lies with the laptops internal wifi settings, after re installing my internal wifi's driver to a more recent version the problem is still the same, I am using a lenovo t61 laptop and my wirless router is a D-LINK DSL-240R, please help with any suggestions on how to fix my internal wifi so that its speed is a constant 54Mbps as my 2 other laptops and notebooks are all at 54Mbps, because of this I believe this is an isolated problem. Many thanks


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## etaf (Oct 2, 2003)

you mention USB wifi dongle and internal wifi - most laptops have an internal wifi - why do you have the additional USB adapter 
there maybe conflict in the utilities managing those wireless adapters

can we see a xirrus screen shot and also a device manager screen shot 
*------------------------------------------------------------------------*
* Run Xirrus Wi-Fi Inspector  
Download and install*
If you cannot access the internet with this PC, then you will need to copy the program across to the faulty PC
Save the file to a USB flash drive or other removable media. Plug it into the working computer with internet access and copy the file and install the program. 
You will now need to take a screen shot and copy that back to the working PC and attach the screen shot in a reply on the forum here.

http://www.xirrus.com/Products/Wi-Fi-Inspector.aspx
Direct link to the program is here http://info.xirrus.com/Wi-FiInspectorConfirmation.html

_{If the above link does not work heres another link http://www.pcworld.com/downloads/file_download/fid,77196-order,4/download.html}_

Then run and install the program - on a wireless enabled PC/Laptop
if you get an error - You need will need to have NET Framework installed for the WiFi Inspector to function.

Run the program

A user guide is available here http://www.xirrus.com/cdn/pdf/Xirrus-Wi-Fi-inspectorguide-1-2-1-RevB-6.aspx

post a screen shot of the program running.
if there are a lot of networks showing can you click on *"networks"* top lefthand area - so we can see all the network information.

post which *SSID* name is yours, its located in the list, under_ network "Adapter Name" _(1st column) 

To post a screen shot of the active window.
1) hold the Alt key and press the PrtScn key. Open the Windows PAINT application (Start> All Programs> Accessories> Paint) and Paste the screen shot. You can then use PAINT to trim to suit, and save it as a JPG format file. 
OR
2) if you are using Vista/Windows 7 you can use the "snipping tool" which is found in Start> All programs> Accessories> Snipping Tool

To upload the screen shot to the forum, open the full reply window ("Go Advanced" button) and use the Manage Attachments button to upload it here.
Full details are available here http://library.techguy.org/wiki/TSG_Posting_a_Screenshot

Note:
For a reliable (or robust as the Xirrus user guide says) wireless connection you need a signal of about -70 dBm or better. "A desirable signal level for a robust Wi-Fi connection will be green".
note: the signal level is a negative number, so for example -88 is worst and -40 is better

If you are using the Mac OS then use http://www.istumbler.net/ or
if you want to optimise base station position and signal strength / dead spots use
http://www.chimoosoft.com/products/apgrapher/ which has a graph function to monitor signal
*------------------------------------------------------------------------*

*------------------------------------------------------------------------*
* Device Manager *
Post back the results in device manager
You will now need to take a screen shot and copy that back to the working PC.
Save the file to a USB flash drive or other removable media. Plug it into the working computer with internet access and copy the screen shot and attach the screen shot in a reply on the forum here.

how to access device manager for different windows versions
http://www.computerhope.com/issues/ch000833.htm

Hold the *Windows* key and press *Pause* key, should open to allow device manager to be seen

on a laptop you may need to use Hold the *Windows* key and press *FN* key + the *pause* key

if this does not work then -

Windows 7 or Vista
Click on the Start Orb
In the Start Search box type
*device manager* and then press enter

-------------------

Start > control Panel {Vista set to classic view}> system > {Vista, device manager on left hand side} {XP hardware Tab, device manager button} > 
windows 7
start > control panel> System and Security> Device Manager

*network adaptors, click on the + * > post back the devices listed there

post a screen shot of the device manager - network adapters

To post a screen shot of the active window.
1) hold the Alt key and press the PrtScn key. Open the Windows PAINT application and Paste the screen shot. You can then use PAINT to trim to suit, and save it as a JPG format file. 
OR
2) if you are using Vista/Windows 7 you can use the "snipping tool" which is found in Start> All programs> Accessories> Snipping Tool

To upload the screen shot to the forum, open the full reply window ("Go Advanced" button) and use the Manage Attachments button to upload it here.
----
Full details are available here http://library.techguy.org/wiki/TSG_Posting_a_Screenshot

-----
http://www.techsupportforum.com/forums/f136/how-to-use-windows-device-manager-655905.html

*------------------------------------------------------------------------*


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## TerryNet (Mar 23, 2005)

Make sure you have the latest wireless driver from Lenovo's web site.


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## pcfeer (May 1, 2007)

Hi, I am using a wifi dongle so that I can use the laptop with the internal wifi problem at 54Mbps there is no conflcit between the 2 devices as I have never used the dongle until now, the fluctuation in the wifi speed is only on the internal wifi and although in my screenshot it shows 54Mbps it often decreases and increase like this 54 - 34 - 28 -18... all the way down to 1Mbps and then will just go up and down to 48, 54 etc etc as stated I have 2 other laptops working fine over wireless and like the wifi dongle all keep to a constant 54Mbps yet this laptop does not my SSID in the xirrus screenshot is the DSL12345 which I renamed but is actually a D-LINK DSl-240R. please note that if in these screenshots all appears to be fine with the 54Mbps I am not mistaken and this fluctuation does occur on the status page it just happens to be at the time of taking the screenshots that it was stable. Many thanks for your help.


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## etaf (Oct 2, 2003)

you have another signal on channel 1 so i would log into the router and change the wireless signal to use channel 6 or 11

also as pointed out by TerryNet - make sure you have the latest drivers for the adapters


> Hi, I am using a wifi dongle so that I can use the laptop with the internal wifi problem at 54Mbps


 dont understand 
also on the device manager only 1 wireless device is showing 


> the fluctuation in the wifi speed is only on the internal wifi and although in my screenshot it shows 54Mbps


 which I guess you removed the USB as the internal device is the issue


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## pcfeer (May 1, 2007)

I have changed to channel 6 but the problem still occurs and also I am using a wifi dongle so I can use the laptop that has the internal problem normally


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## etaf (Oct 2, 2003)

have you updated the driver ?


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## pcfeer (May 1, 2007)

yes the driver is the most recent available


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## etaf (Oct 2, 2003)

can we see another xirrus screen shot


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## pcfeer (May 1, 2007)

I managed to take the shot during the fluctuation which you can see in the image name xirrus wifi2 if this helps


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## etaf (Oct 2, 2003)

they look ok

try a tcp/ip reset and if that does not help - then reinstall the adapter

*Uninstall and allow windows to re-install the adapter and Driver*
I would goto device manager and right click on the adapter and uninstall/remove and then restart the PC and let windows re-detect the hardware and reinstall the driver

*------------------------------------------------------------------------*

*TCP/IP stack repair options for use with Vista/Windows 7*

Start> Programs> Accessories> and *right click on Command Prompt, select "Run as Administrator" * to open a command prompt box
(A new dialogue box - black with white font, will appear on the screen ):

In the command prompt window that opens, type the following commands:

_Note: Type only the text in *bold* and *red* for the following commands._

Reset WINSOCK entries to installation defaults: *netsh winsock reset catalog* and press _enter_

Reset IPv4 TCP/IP stack to installation defaults. *netsh int ipv4 reset reset.log* and press _enter_

Reset IPv6 TCP/IP stack to installation defaults. *netsh int ipv6 reset reset.log* and press _enter_

ReStart (reboot) the machine.

If you receive the message 
*The requested operation requires elevation.*
Then please open the command prompt as administrator - as requested above 
Start> Programs> Accessories> and *right click on Command Prompt, select "Run as Administrator" * to open a command prompt box
(A new dialogue box - black with white font, will appear on screen ):

Please note and post back - if you receive the following message :-
*Access is Denied*

please post back the results in a reply here - its important we know that these commands have worked correctly and not produced any errors
right click in the command prompt box
select all
enter
control key + C key - to copy
then reply here and 
control key + V to paste

Details also here
http://support.microsoft.com/kb/299357

*------------------------------------------------------------------------*

*TCP/IP stack repair options for use with Windows XP with SP2/SP3*

*S*tart, *R*un, *CMD* to open a command prompt box
(A new dialogue box - black with white font, will appear on the screen ):

In the command prompt window that opens, type the following commands:

_Note: Type only the text in *bold* and *red* for the following commands._

Reset TCP/IP stack to installation defaults, type: *netsh int ip reset reset.log* and press _enter_

Reset WINSOCK entries to installation defaults, type: *netsh winsock reset catalog* and press _enter_

ReStart (reboot) the machine.

Please note and post back - if you receive the following message :-
*Access is Denied*

please post back the results in a reply here - its important we know that these commands have worked correctly and not produced any errors
right click in the command prompt box
select all
enter
control key + C key - to copy
then reply here and 
control key + V to paste

Details also here
http://support.microsoft.com/kb/299357

*------------------------------------------------------------------------*


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## pcfeer (May 1, 2007)

Hi I tried those commands and reinstalling the wifi driver but the fluctuation still occurs, I am using a DSL-2640R which often disconnects from the internet but I believed this was a separate event but now would like to include the router as a possible cause if this can have an effect on speed fluctuations?


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## TerryNet (Mar 23, 2005)

TerryNet said:


> Make sure you have the latest wireless driver from Lenovo's web site.


You have not yet confirmed that you have done this. Many things can cause your speed fluctuations. The most common cause, especially with an Intel adapter I think, is incorrect driver.


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## pcfeer (May 1, 2007)

Hi, sorry for being unclear but I did download and install a wifi driver from lenovos website however there are 2 available for windows 7, firstly "Intel Wireless LAN (bg, abg, abgn) for Windows 7 (32-bit, 64-bit), Vista (32-bit, 64-bit), XP - ThinkPad" and second "Intel Wireless LAN (11bgn) for Windows 7 (32-bit, 64-bit) - ThinkPad", I had downloaded and installed the first named driver however I may be mistaken but it seemed that during installation their may have been some kind of intervention by a windows update which seemed to install an intel driver however I am unsure of this but when checking on the device manager properties for the driver and all licences and names are either intel or microsoft which does suggest I have an intel one installed but I am not sure if this is what lenovo was offering?


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## TerryNet (Mar 23, 2005)

Seems like one of those drivers should have included "4965AGN.," so the one you downloaded seems right. Wouldn't hurt to install again just to make sure.


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## pcfeer (May 1, 2007)

Hi I re download and installed it but still no change and this is the 5th time now so Im fairly sure its not the driver.


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## TerryNet (Mar 23, 2005)

Probably a defective adapter. If you can access it through a cover on the laptop's bottom remove and carefully and firmly replace it several times. This will fix any possible corrosion or looseness. Make sure the antenna leads are secure.


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## pcfeer (May 1, 2007)

Hi, the lenovo t61's adapter I belive is at the very top of the screen section of the laptop making it hard to access however before I even attempt this I am going to test the laptop at a friends house to see weather the fluctuations occur while I am connected to his router and if they do not occur then I can assume it is my already defective DSL-2460R and hopefully get a free replacement from my isp. thank you very much for you assistance.


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## TerryNet (Mar 23, 2005)

Good idea. The router is not totally bad, as you have other adapter's working OK with it. However, there are instances of a particular adapter and router not playing nice together.

I would not mess with the screen area of a laptop; too much chance of damage from people like me who are not skilled in that kind of work.


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## pcfeer (May 1, 2007)

well I personally belive the problem with the router is signal strength, it is already running at maximum transmit power and the adapter that is working fine is no more than 50cm away from the router and runs at a constant 54Mbps whereas my laptop and the other one which has a fluctuation are in other rooms or are downstairs, though I must admit my routers location goes against most set guides, it is not connected to the master socket and it is low down and next to a wall so perhaps I should test it in a more open location perhaps from the master socket and see if this has any effects also?


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## TerryNet (Mar 23, 2005)

You've showed the signal varying from -51 dBm down to -58 dBm. That is plenty strong enough, but the variance is a bit worrisome if it really caused by the router rather than the adapter.


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## pcfeer (May 1, 2007)

Hi, just to update I tested my laptop out at college and the signal was a constant 54 Mbps so I am now certain that either my router is faulty or there is some interference, I decided to google "wifi issues with t61" as my laptop is a lenovo t61 and I came across another forum where someone was having similar problems with another product made by D link so I am going to attempt to contact AOL and see if they can send a new hopefully different type of router and this should hopefully solve the problem though I thought I would post here and get your expert opinions, many thanks


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## TerryNet (Mar 23, 2005)

Possibility of interference from another device, such as a 2.4 GHz cordless phone or baby monitor, but my top suspect is a faulty router. The brand and model of router probably doesn't matter.


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## pcfeer (May 1, 2007)

Hi, I decided to use a longer adsl lead and take my router onto the landing and my speed has increased to the 54Mbps mark and is constantly there, I then however suffered the same drop with my downstairs laptop which is stationary in 1 room so to make up for it I moved this laptop in the other room nearer to the landing and it now also has a much higher speed than before so it turned out that the problem was the routers lack of range and the low gain antenna that the model comes with. Thank you very much for all your assistance


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## TerryNet (Mar 23, 2005)

You're welcome.  Glad you tracked down the real cause of the problem.


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