Newbie question (might be stupid…)

Hi there,

I have an Airport Time Capsule which I use on the 2.4Ghz band, all settings standard. It automatically chooses the channel (6 in my case), WPA-2 and it uses Mode n. I use a Macbook Pro Retina as a client, all pretty new stuff.

If I look at the SNR bar in NetSpot I mostly have orange bars with a signal of -60 or so. Even if I walk to the Time Capsule and try directly next to the machine it takes a while for the bar to go to green, but the Signal remains negative, substantially better at -5 to -10 or so. But still not what you would expect.

The strange thing then is that when I walk back to my work space, which is around 10 meters away, same floor, no massive concrete walls in the direct line between the Time Capsule and the Mac, it somehow seems to “remember” the connection and then suddenly is green for a few minutes. Then it drops again to orange with very low Signal. Again strangely enough I start working on the Mac and every now and then it picks up the full green bar again.

Mainly three questions:
-what is the definition of the Signal? It clearly is not the difference between measured signal and background noice I think?, so the optimal value is nil? Or do I misunderstand this?
-is it normal for the Signal to vary that much with a Mac that is not being moved?
-what is now actually a Signal value that is normal a) when you have the Mac next to the Time Capsule, and b) if you are about 10 meters away with no real obstacles in a straight line?

BTW, the reason I am asking is that I bought additional Airport Extreme devices to beef up the wifi network in the rest of the house based on the headmap provided by NetSpot, but I first want to learn what is normal, ie what to aim for.

Any feedback much appreciated!

thx

Arnoud (NL)