Airport - DONT use "interference robustness"

I'm using an Airport extreme base station with an airport extreme laptop.
I've been suffering bad signal for the last two weeks (with Tiger)..
I've discovered that it was caused by switching on "interference robustness" in the client -its a tickable option in Internet Connect.

With the feature ticked I get noise of -40dbm.
Unticked noise reduces hugely to about -80dbm.
Since my signal is about -60dbm, the tick switches me between almost unusable performance, where it struggles to communicate at 700kb/s-1Mb/s, and full performance at a totally reliable 5.4Mb/s.

I don't know how this can happen. Just keep that feature unticked - should be called "communication suicide".

Don't know how it got ticked, maybe I tried it just after Tiger upgrade, or maybe it just happened, and needs checking.

To check signal and noise, get "Airport Client Monitor" from the Apple support site (airport). I think it comes in free download "Airport Management Tools" or something like that.

By it's nature, interference robustness is going to kill your connection performance. It attempts to filter as much noise as possible out; you'll probably drop to about 15Mbps max throughput (as opposed to 802.11g's theoretical 54Mbps max).

Your best bet is to make sure neither you, nor any of your neighbors (if possible) are running any 2.4 ghz cordless phones (unfortunately, 2.4 ghz is the most popular now), as these will cause unavoidable interference and degrade your connection, causing alot of packet loss, disconnects etc.

Additionally, other base stations in the area will cause problems - make sure you set your base station channel to one that isn't in use by other nearby bases.

You can also in advanced setings in the AEBS admin utility, adjust transmitter power on the base station.

Past that, the closest you are to the base, the better; if you sprung for the higher end airport extreme base station, you can hookup an external antenna which can make a big differencde as well.

Thats what I expected too, Ritalan. I was using a 2.4GHz cordless phone right next to the computer regularly. I suspected it might be the culprit. I did extensive tests, before and after I discovered the "interference robustness" thing, and using different airport channels.

To my absolute amazement, and contrary to everything I read, I could detect absolutely no deterioration in airport bitrate, even with the six phones in the house all on, nearby, and a call being made. The phone "base station" is right next to the airport one.

I did similar tests with bluetooth. Couldn't get any deterioration at all. Shouldn't be so, but thats what I found. So now I use phones and bluetooth without worry.

I have no explanation.

My Airport Extreme base station crashes frequently when it passes corrupted packets if Interference Robustness is not enabled.

If you use Interference Robustness, your maximum network throughput will actually become 11 Mbps, the same as 802.11b. This is quite sufficient for Second Life.