Airport/Wireless signal


We have 2 identical Macbook Pro's OSX 10.6.8. We share a router.

One laptop gets an excellent wireless signal and is stable.

The other laptop experiences a weaker signal, will sometimes disconnect and is generally unstable.

Can anyone suggest what might be causing this and/or a remedy??

Yes this sometimes can popup with OS X "upgraded" systems. So read the following articles:
a) Troubleshooting Wi-Fi issues in OS X Lion and Mac OS X v10.6
b)Addressing self-assigned IP addresses after installing OS X 10.6.8
c) Download and install the 10.6.8 "combo update (it will not over write you applications etc). This might help.
d) Read my wireless fixes post [HOWTO] Reset the wireless Airport Card settings in OS X (10.7.x + 10.8.x). Most of the tips will help you in 10.6.x.

Try all these tips in the affected machine. Plus download the free utility iStumbler 99 and make sure your wireless router is on a different channel than others around you, you might be having wireless "crosstalk".
Thanks and apologies for tardy reply. We have been away from home.
I have been working through your suggestions and have....
reset the router but I cannot find a facility to change the MTU settings??
downloaded and installed iStumbler99

I cannot find the 10.6.8 combo update??

Now and again I get a pop up saying "another device on the network is using your computers IP address. Is that significant??

Still got some other things to try but grateful of any further advice. Thanks. Peter
Is one of the machines running parallels?

My laptop is running Parallels and I'm getting occasional "There is another device on your network using your computer's IP address". The message went away when I upgraded and came back when I reinstalled Parallels. It doesn't happen often.

I have also noticed slow wireless activity. Again I put it down to Parallels. I have found it downloading updates in the background.

But it's not a continual problem. Just happens from time to time and seems to be when Parallels is running.
Thanks. I cannot find any reference to "Parallels" on either laptop. Is it an Application? What does it do??

Parallels is one of the apps that you can install, allowing you to run Windows (or a variety of other operating systems) in a virtual environment, while the host system (OS X in this case) continues to run.
Part of what that virtual machine does, is to provide network interfaces for use by that operating system. One result then, can be that the virtual network interface may create several connections to your network, or your router - and some kinds of software may report problems with the network connections, even though some may exist only as a virtual connection, and not a hardware network interface.
That all sounds confusing when I read it, so perhaps that can also cause odd system messages.
Those apps that can provide a virtual system can be Parallels, or VMWare Fusion, which are both commercial apps. Then there's VirtualBox, which is free software. There's a couple of other similar products, too.