Weak Wifi

[MotleyPete]

I have a router in the next room (for logistical reasons) and an iMac sitting in the next room that shows all four WiFi bars, all day, every day. However, my Mac Pro which is sitting right next to the iMac has gone from initially having three bars to more regularly getting only one or two bars. In fact it goes up & down throughout the day. The iMac is getting fast internet speed 24/7, the Mac pro has varying slow speeds and even stalls.

The suggested fixes I have tried are:
• "Turning it off and on again" ...obviously
• Checked with iStumbler to see if a neighbour is using the same channel & none are.
• Reset the PRAM.
• Made a new location in the Network Preferences, switched, switched back again and deleted it.
• Turned off IPv6

Does anyone else have any suggestions? I have no idea what else to try. I have only recently re-installed Snow Leopard, so it's a pretty fresh system.

 

[Hellhammer]

Has it been so since you got it or did it occur recently?

 

[MotleyPete]

Has it been so since you got it or did it occur recently?

Recently.

A few weeks ago I moved the thing into the next room because I had telephone wire strung out through the house. It was a very impractical and messy setup that had to be moved when I decorated. Initially after the move I got three bars which was liveable with and didn't bother me. Now it just seems to go up and down on a whim, but mainly down, whilst the iMac (sitting next to it) remains rock solid on all four bars. Even the Macbook downstairs has all four bars and no problems.