I've read the exact same symptoms to my problem on this thread on the MacBook Pro Forum https://discussions.apple.com/thread/1352518 but my problem is with my Mac Pro. I cant find any information on that thread that works for me. I'll briefly describe the problem below if you cant be bothered reading "ffredburger"s post.
I have my house set up with the wireless modem/router in the kitchen and use wireless to my Mac Pro upstairs.
I have a PC laptop which also uses the wireless and has never had a problem.
My Mac Pro loses access to the net every few minutes or so. I usually follow a sequence of "Turn AirPort Off" / "Turn Airport On" to cycle the connection, and this works but only for a temporary solution until it drops out a few minutes later.
also link to pic here.. http://i.imgur.com/k1oTi.png
It always shows full bars even though in the activity monitor it just flatlines or flutters near 0kB/sec.
Like many others, my connection drops although the wireless signal icon remains full.
I've noticed that as long as my system doesn't idle (ie - if I'm downloading something, or on a webpage which is always sending or recieving data) the wireless connection seems alright. But if I am on a webpage (for instance, this Apple website which is idle and not sending or recieving data) for a few minutes or am away from the computer for 5 minutes, the connectivity dies and I cant access the net. I then follow a sequence of "Turn AirPort Off" / "Turn Airport On" to cycle the connection, and this works but only for a temporary solution until it drops out a few minutes later.
My PC Laptop has never had any issues.
My wireless modem/router has been checked and troubleshooted but no solution.
My ISP have came and checked my phone line but no solution.
I recently upgraded to Leopard, hoping that would fix this issue but no solution.
Tried all the updates but no solution.
If anyone can help me it would be much appreciated as I cant find anything to work.
Also, can I ask that NO ONE suggest that I hook my computer up via the ethernet cable as there is no access points upstairs and I'm not going to pay a tonne of money to get one installed when I paid a tonne of money for my "AirPort Extreme" so I didnt have to (which was just over 2 years ago).
Its been a constant problem for the last 12 months and the short-fix of "Turn AirPort Off" / "Turn Airport On" to cycle the connection has driven me to madness (especially when I write a lot of information into a site for example this, and after 15 minutes I click the next button or send and dont realise the net is no longer connected and I LOOSE EVERYTHING I'VE JUST TYPED. It's happened 1000's of times. Also because I used to work from home and I was getting paid by how many questions/solutions I did in an hour and my pay was half of what everyone else was getting due to all the drop outs and loosing data I'd spent 5 minutes typing)
ps - here's my system info below
also link to pic here... http://i.imgur.com/QOVBB.png
Also here's some info about my wifi in my "System Information"
CoreWLAN: 2.1.2 (212.1)
CoreWLANKit: 1.0.2 (102.2)
Menu Extra: 7.0.2 (702.1)
configd plug-in: 7.1.2 (712.1)
System Profiler: 7.0 (700.3)
IO80211 Family: 4.1.2 (412.2)
WiFi Diagnostics: 1.0.1 (101.1)
AirPort Utility: 6.0 (600.92)
Card Type: AirPort Extreme (0x14E4, 0x88)
Firmware Version: Broadcom BCM43xx 1.0 (18.104.22.168.11)
MAC Address: 00:1d:4f:fe:c7:f6
Country Code: US
Supported PHY Modes: 802.11 a/b/g/n
Supported Channels: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 36, 40, 44, 48, 52, 56, 60, 64, 149, 153, 157, 161, 165
Current Network Information:
PHY Mode: 802.11n
Country Code: US
Network Type: Infrastructure
Security: WPA2 Personal
Signal / Noise: -87 dBm / -87 dBm
Transmit Rate: 52
MCS Index: 5
Message was edited by: quinndagit PLEASE HELP!