Electronic – How to build a cheap device to determine where Wi-Fi interference is coming from


In this post, the ServerFault guys use a fancy tool to map out the WiFi spectrum under normal conditions, with a microwave running, and with a baby monitor on. The baby monitor and microwave cause a surprising amount of interference.

Having had to deal with Wifi interference in the past, a tool like that could be very useful. However, its price – $200 to $1000+ – is way outside my price-range.

I'd like to build something to serve a similar purpose, but my experience with building analog devices is, shall we say, non-existent.

  1. What's the cheapest way to determine where Wi-Fi interference is coming from? My idea was rig up an old radio to somehow receive around the 2.4Ghz frequency, but I have no idea how to do that.
  2. How can I tell which channel has the least interference?

Please let me know if this is off-topic. Thanks!

Best Answer

The WiSpy is based on a Chipcon (now TI) CC2500 chip, which is a general-purpose 2.4GHz digital radio. By scanning through the channels, it can be turned into a spectrum analyzer. http://tim.cexx.org/?p=646

So you need a board with a CC2500 radio. Search ebay for "CC2500" and you can find them for http://www.ebay.com/itm//260900652131

Here is a similar project with a Chipcon chip at a different frequency: http://ossmann.blogspot.com/2010/03/16-pocket-spectrum-analyzer.html