How can I monitor signal strength of an access point?

Question

Is there a way to monitor the signal strength of an access point? I'd like to monitor the strength of signals the AP is "hearing". I want to monitor from a workstation on the same LAN, connected (through a router) by wire to the AP.

I know how to monitor the RSSI of a wifi client hooked directly to a computer. (WiFi Analyzer on my Nexus works great.)

Ultimately what I want to do is monitor two APs (both on the same LAN with the workstation, each connected by wire to the router) to see if/when the APs are radio-visible to each other.

I'm more or less a network noobie. I've looked around, done lots of reading, but can't figure out if what I want to do is even possible. I know at least some APs communicate directly, since that's how (some?) repeaters work.

I'm comfortable doing some coding if that's necessary. But with all the tools for exploring wifi networks I feel like I'm missing something obvious.

Edit to add information: I have a region which looses wifi connectivity. The area has complicated, changing, environmental things going on - many of which could impact a wifi signal. I want to monitor wifi signal so I can (try to) correlate loss of good signal with other things going on. (For other reasons it is not appropriate to just add a strong AP in that region.)

My current thinking is to run a Kismet drone on an old WRT54G (placed in the region of interest). I haven't done that, but I am hopeful I can figure out how to do it. The Kismet drone will send info back to my workstation (running Kismet), I can get timestamped RSSI info, and go from there.

As I said, haven't done it, so still not sure if that's what I want, nor if I can do it, but that's the direction I'm headed at the moment. I am open to suggestions.

Answer 1

Typically you can't measure the signal strength between two APs in the way you are thinking (there are some enterprise grade products that have some ability but it is expensive kit!)

I presume you have some sort of issue with overlap between two APs, judging by the question? It may simpler just to check the channel spacing between the two. Typically on the 2.4GHz band channels 1, 6 and 11 are used as these are non-overlapping.

If that is not the issue, can you expand a little and tell me why you need to measure the signal between two APs, as there might be another solution.

Answer 2

I don't quite understand whether you want to see how good your computer's connection to the AP is or if you want to know what other networks the AP sees.

For your computer, it depends on the OS; for Windows you can try Network Stumbler, for Linux use the aircrack-ng suite which includes airodump-ng, an utility that can (among many other things) display all the networks including their signal strength in real time.

For your router it's a bit more difficult, if you have shell access to it then it's probably running some sort of Linux and you can compile a version of aircrack-ng for it, install it and use it just like on a computer (you'll need to stop the process that manages the AP while doing this, for Linux-based routers it's most likely hostapd).