Sorry guys, first a gripe about my neighbor's WiFi access point (it is related): they totally hog the center nine 2.4 GHz channels (3-11), centered right at 7! I know the outer regions of the signal don't make as much of a difference, and technically they're running channels 5 & 9. Anyway, their signal is clearly interfering with mine, which is necessarily centered at 3 or 11 to evade their interference. I guess it's somewhat a case of access point envy: they happen to have both a stronger signal and a higher data rate, while occupying twice the band width that I do.
Getting to the point, I've noticed that they tend to sit nice and pretty centered at 7, but they definitely auto-select their channel, and I've noticed that the auto-selection algorithm tends to shift towards the higher channels; hence I decided to pick channel 3, and I don't get so many intermittent lag spikes any more.
Anyway, the thing that weirded me out was the reason they have to auto-select sometimes: unexplained, powerful (talking order of 0dB here), giant spikes of 2.4 GHz activity in consistent regions of the spectrum. I don't think it's just noise, since my wireless monitoring software is registering a MAC address, a manufacturer, and usually a fairly coherent ascii name… and it seems to be a fairly well-confined signal. But these signals are fairly common, and they do some weird stuff to my signal.
So my question is what are these signals? Where are they coming from? Where are they going? Why are they so ridiculously strong? Why don't they ever last very long?
Here's an inSSIDer screenshot I took, for your perusal. I am labeled with "me", my greedy neighbor labeled with "neighbor", and the 2 quasar signals are labeled with "WTF?".
Best Answer
I see the same 0dB spikes when running inSSIDer 2.1. Because they don't seem to cause a disconnect to APs on the same channel as the spike, it seems possible to me that they are not really 0 dB "spikes", but really signal drops.
That is, if some nearby APs are occasionally blasting out signal at orders of magnitude higher amplitude, then I would expect severe issues with my WAN. Because I don't see any issues associated with these "spikes", I think it possible that they are a bug in the way the inSSIDer software plots signal. If signal below some arbitrary lower limit, for example -100 dB, is rounded off to nothing, that "nothing" might be encoded as "0". Unfortunately "0" dB is a very high signal not a very low signal. So when plotted we see your "quasar" effect.