[TriLUG] WiFi quality monitoring

[Joseph Mack NA3T]

On Thu, 14 Aug 2014, Igor Partola wrote:

> So my laptop is overloading the router's Wi-Fi module by transmitting to
> it?

No. The amount of power from a wifi card, 50mW, isn't going to cause intermod, 
even on a device sitting next to it.

> Or an external non-Wi-Fi signal is overloading the router's Wi-Fi
> module?

Yes. You'll need 1W from a device sitting next to it, 1kW from a device 100yrds 
away or 1MW from something on a tower a mile away.

> Or do I have that backwards? And the 10 mV of received signal is
> going to put the router into overload? What's a typical voltage when
> receiving the signal?

1-100uV.

> Should I try putting the original antennas back on to see if the problem goes 
> away?

yes. If that doesn't make any different, try an opened paper clip instead. Sure 
you wont't have much range (maybe 10ft), but it will show if the problem is 
external rf.

> As for hams in the area, I honestly don't know if there are any. This
> neighborhood could certainly contain some. There is also a rock quarry and
> a few construction trucks in the area doing work on people's houses so I
> wouldn't be surprised if they used walkie-talkies or CB radios.

A CB radio on a truck isn't going to do it.

> I am pretty high up on a hill as well so I could be catching some other type 
> of RF signal.

You would need to be in sight of something firing right at you, even if it were 
through trees.

> In my ideal world I'd love to grab a spectrum analyzer and see
> what's going on over time, but unfortunately that would be an expensive
> attempt.

yes I couldn't find one when I had my problem either. Only a well equipped 
electronic shop would have one.

> Don't see any yagi's around, but the area is pretty wooded so I cannot see
> much at all.

It's a long shot. For the ham to do anything, his antenna would have to be above 
the trees too. If you can't see them, he isn't there.

> The house was built 16 years ago and has wood siding. I cannot
> say what kind of insulation it has under the siding. The router sits in a
> corner where both walls are outside walls.

what's the difference in signal on your laptop on the inside of the wall, 
compared to the outside of the wall 1 foot further away?

John M suggested turning down the power on your wifi box. You have it at quite 
high power and it will be generating a lot of hash (it won't be linear anymore). 
This will mess up other equipment around. Possibly it could affect your wifi 
cards in your laptops or other wifi listeners, but if it wasn't happening in 
your old place, then it isn't a problem.

Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!