On Wed, 18 Dec 2013 09:19:56 -0800, Jeff Liebermann wrote:

http://farm8.staticflickr.com/7299/1...48f3922e_o.jpg

Looks like you have interference from someone nearby using Ch 9.

I'm still amazed that you saw that, lurking inside the graphs!

You must have eyes like an eagle, because I had not seen it
(until you pointed it out).

Although, for the life of me, I can't determine the *source*
of that channel 9 interference since nothing inside the house
or nearby seems to have a strong enough signal to register as
channel 9 WiFi...

For example, here is a scan on my laptop for access points:
http://farm8.staticflickr.com/7364/1...a0cdf3b1_o.gif

Nothing is on channel 9.

Here is a scan of the access points from my radio:
http://farm6.staticflickr.com/5484/1...32590c4f_o.png

So, I do agree with you that there is a good amount of channel
9 interference; but I must conclude the source of that noise
is distant (but clearly in the path of the radio).