Why does signal strength vary on my Westell 327W?

[#1]

My wife uses her laptop about 40 feet away from our router, in our house (conventional wood construction, no wireless devices or wireless phones in use in the house, in the suburbs). 

Her signal strength varies during the day from low to very good--sometimes going from 1 to the other in one minute.  I'm in the 'burbs, and there are not a lot of houses near mine.  Can someone tell me why her signal strength should vary so much, and what I can do about it?

[#2]

#1 Do have any cell phones or wireless phones?

#2 Does this happen when someone is using a microwave?

#3 Do you have any big screen TVs? For example, points to another thread..

URL: http://forums.verizon.com/vrzn/board/message?board.id=High_Speed_Internet&thread.id=2230

Title: Wireless doesn't work near big-screen TV?

^^

[#3]

DSJR>   #1 Do have any cell phones or wireless phones?

No.

DSJR>   #2 Does this happen when someone is using a microwave?

No.

DSJR>  

#3 Do you have any big screen TVs?

NO.

I've seen signal strength fluctuate while I'm looking  at the screen--with nothing else going on in the vicinity.

[#4]

No, hmm...

#1

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@MrCurious2 wrote:
with nothing else going on in the vicinity.

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Not even other radios (Like police officers, fire fighters, medial personal) in the area in use?

#2 What Firmware is it running?

If you have no idea of what I mean, take a screen shot of least the first screen that you see in the router - and post it.

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For Windows, this means:

Pressing the "Print Screen" key on your keyboard, going to paint (Start--->All Programs--->Accesories--->Paint), pressing CTRL and P at the same time, saving the file as a JPEG (use "save as type" as need be), uploading it some where (I use tinypic.com - unless a message board allows uploading the image directly), and giving out the URL of the image..

^^

[#5]

1.  I often have stereo operating in my office, about 5 feet from the router.  My wife has a portable radio in her office.  No other radios of any kind in the house are turned on.  And certainly no "advanced" electronic devices beyond our computers.  I've been standing in front of her computer while the signal strength changed.

2.  I went to 192.168.1.1.  That page shows 3 panels:  My Gateway, my network, and Action Zone.

The My Gateway panel shows the following (excerpt):

    Internet Status:  Connected

DSL link: 

Connected Speed (Down/Up): 

     861 Kbits/sec by 156 Kbits/sec

Connection Type:  PPP

Username:  newdsl

[#6]

Ok.

What is the top?

For example, left to right on the top...

a) Wireless Setup, Network Connections, Security, Parental Controls, Quality of Service, Advanced, System Monitoring?

Which looks something like the screen shot at http://www.portforward.com/english/routers/port_forwarding/Actiontec/MI-424-WR/1st_SMTP_Server.htm

OR

b) Main, Wireless Settings, My Network, Firewall Settings, Parental Controls Advanced, System Monitoring?

Which looks something like the screen shot at http://www.portforward.com/english/routers/port_forwarding/Actiontec/MI-424-WRv2/1st_SMTP_Server.htm

?