Airport Extreme, 5Ghz connectivity problems and poor media streaming

Question

Hi,
I purchased an extreme from the apple store a little over a week ago, and before I send the device back I would like to solicit recommendations from this forum.
Some information about the setup:
- Single airport extreme (supplying wifi services for my non-wifi DSL router and a connected USB disk)
- Airport Extreme Firmware: 7.4.2
- iTunes: 9.0
- OS: Snow Leopard (10.6.1), Leopard (10.5.8), Window Vista.
- Harddrive: 2TB lacie, USB2.0 connection only
- 2.4 and 5 Ghz broadcasting mode
- The device is broadcasting on all supported protocols.
- Multiple clients (various: apple, microsoft, fujitsu)
- Small space, no major concrete/brick/stone walls, signal strength is 5 bars of goodness
- Country: Spain (I know there were 5Ghz restrictions here a while ago, but the device broadcasts on 5Ghz and is therefore not crippled).
If anything else could be of use, let me know and I'll update this list.
And now the problems:
1) 5Ghz connections fail
When connecting over the 5Ghz freq my connectivity to the extreme and the services it is offering (internet, disk sharing) is intermittent, at best. Basically, it has not worked reliably since I took it out of the box. This is equal for both of my macbooks and a fujitsu laptop (all with n support).
I've tried switching channels to avoid congestion - I don't live in a wifi-heavy area, and there are no other likely sources of interference (e.g. microwaves, cordless phones).
My connections to mounted disks come and go, I have to re-authenticate, and so on.
A general scan of the environment with KisMac does not show any major interference from other wifi networks (only 2 others in range, one is wimax).
I've tried to do some wifi analysis to see if I can spot any frame/packet related issues. Some rudimentary analysis indicates that when the connection stops working on the 5Ghz channel my laptop continually sends request-to-send packets to the extreme, but does not receive a clear-to-send. This occurs after a-few-seconds to a-couple-of-minutes of connectivity - the connection initially 'works' (i.e. wifi packets are sent/received correctly and I can access the internet).
2) Data access and media streaming from the connected USB drive is very poor
I've mostly had problems with itunes. I thought this might be related to the size of my library, but this shouldn't effect single track playing. Even enabling large buffering in itunes results in intermittent pauses and long track loading.
Note: this occurs over b/g connections; as stated already, n connections don't work. iTunes simply goes into a coma for while and then eventually fails. See above. Also, if I just stream from my macbook (i.e. HD connected via USB), it works flawlessly.
The extreme was running 7.4.2 - updated on first connection. It's now running 7.4.1, as I read on the forums that there were some perceived problems with 7.4.2 (although these perceptions may not be accurate.
Concl(f)usion:
I believe I've ruled out the following:
- Distance
- Interference
- Laptop related issues (the same problem occurs with 2 macbooks and a fujitsu laptop).
- Latest firmware
- Software (apps, OS, etc)
Which leaves me to ponder two possibilities:
a) The extreme is damaged.
b) The extreme is not a good product (surely this can't be so?!)
There is, of course, a c-possibility ... that the collective experience of the online community might be able to offer me an alternative path?
I would be very grateful if anyone could offer any suggestions, tips, tricks, spells or simply a hug before I contact apple to begin the process of explaining the issues and seeking some care.
Many thanks in advance,
Dave.

Answer 1

I have had the same problem. Really frusrtating, expecially since the reason I bought the airport was because of all the wireless congestion in my neigborhood with only 11 channels on the 2.4 GHz spectrum.
Bought my airport dual band about a week ago. It had the firware 7.4.2. After extensive searching, I found other with similar issues. Apparently the last stable firmware may be 7.3.8. I am on 7.4.0 and not having any issues any longer (only testing one day now).
This may solve your issue. Login to your airport and choose manual setup. on the summary page, find 'Version' 7.x" and click on the word 'version'. This will allow you to rollback your firmware. I went with 7.4. Depending on what options you need with airdisk, Time Capsule, rolling back may remove those options, so experiment. You can always go back to 7.4.1 or 7.4.2 from within the interface.
Hope this helps.