I have a very weak connection through my Airport Express. By this I mean not a single Spotify song can play without being interrupted.
My computer is located 6m from the Airport Express in a straight line, with no walls or other obstacles in the way. No DECT phones and no microwave turned on.
Wireless speedtest: download of 0.52Mb/s and upload of 0.07Mb/s
Wired speedtest: download of 23.34Mb/s and upload of 1.80Mb/s with a ping of 43ms.
iStumbler 6m away tells me signal between 35% – 45% and noise around 20%.
iStumbler right next to the Airport Express tells me a signal of around 55% – 60%.
Up until last week things were better, in the sense that Spotify played uninterrupted unless I visit heavy webpages or download big files.
It seems my wired connection is good enough but wireless is awful. How can I fix / debug this further?
Speedtest when I set to channel 3: http://www.speedtest.net/my-result/3297169246
Best Answer
I'm a big fan of Apple's Wireless Diagnostic tool on recent OS releases (find it with Spotlight as it's not in /Applications).
You can use the Utilities window to view real-time performance and also perform a wireless scan to map all close-by transmitters and see if a suggested channel is better than your current channel for your base station.
The one piece of information missing from your post is how your internet speed test compares to the transmit rate your WiFi adapter is communicating to your base station.
If your signal to noise ratio is below 15 or your transmit rate matches the speed test - then you can work on finding a better antenna / channel or affect thins by improving the radio performance.
If the transmit rate is low - that would reinforce your difference between the WiFi speeds and the wired speeds.
Here are a couple of the better threads to help as well:
You can even see how this tool can be used in action in this answer - where I turned on a microwave to show that there was some interference from that device.
If you have an older OS, you can get similar information from the logs and wireless clients section of Airport Utility: (Image from the excellent Anand Tech article on Airport Extreme and Time Capsule - http://www.anandtech.com/show/4577/airport-extreme-5th-gen-and-time-capsule-4th-gen-review-faster-wifi-/8)