Wispy 2.4x signal observation help
Submitted by jeffmeden on Thu, 12/20/2007 - 10:18.
I am brand new to the Wi-spy world, having recently acquired a unit to perform wifi debugging at a nonprofit org I help out on occasion. In doing tests at home and at work, with 3 different computers, I have noticed a very distinct signal pattern emerging. There is a peak at 2413 mhz, and an array of smaller peaks at 2425, 2437, 2449, 2461, 2473, 2495. The test at home suggested a local interference source, since the 2413 peak could grow VERY big depending on what part of the house I was in. I assume it to be a neighbor with some sort of 2.4ghz a/v device. However, at work I see similar (albeit smaller) peaks in the exact same pattern. Is there a chance this is a quirk of the Wi-spy device? The peaks are very minimal and don't stack up to even a distant 802.11b signal, so they aren't much of a nuisance. However, it would be nice to know exactly what I'm dealing with so I can be more effective with this.
Also, while I'm at it, is there any advantage to USB 2.0 for the wi-spy 2.4x? It seems to work well enough on my laptop with only usb 1.0 ports, but does it pick up more information with a usb 2.0 connection?
This is an image of the interface, I can upload the capture file too if that would be of more assistance. As you can see, the peaks are spaced at exactly 12 MHz intervals. I am somewhat novice to the world of RF, so any advice on what might be causing it would be appreciated!
Jeff, thanks for sending in the screenshots! those peaks that are evenly displaced look like USB noise, and the unknown device at 2413 looks like a cordless phone.