Some time ago I mentioned that I was having problems with my wireless network dropping out at home, well I finally got sick of it enough to do something about it. It was getting to the point that it would connect for a few seconds and then drop out. One of the guys at work sent me a link to this:
http://www.metageek.net/products/inssider
Talk about a fantastic tool. It shows the signal level for any wireless networks that the receiver can pick up, even secured ones! I checked it on the PC and my channel (11) was about -72dBm. When we ran this at work, our network was about -60dBm. I also ran it on the laptop and was getting around -66dBm with another one at -85dBm also on 11. As I walked up the hall it got to around -50 or so in the room with the transmitter. When I walked into the front room, two more networks on 6 showed up at -80. There were only 4 networks in total, 2 on 11 and 2 on 6.
I then changed the channel on the modem from 1 to 13 and checked the signal level each time on the PC. The best reception seemed to be around 4-6 so I chose 5 to stay away from networks on 6. I also checked the reception with the Netgear receiver sitting flat and pointing up in the air (it is on a USB cable to get it up higher as our gym is between the transmitter and receiver...lots of metal). This picked up the receive level by about another 6 to 8 dB.
The result? Last night I updated to AVG 9 which required more than 100Mb of download...it never missed a beat!
So now I'm happy Jan 
If you want to check out your wireless reception, I recommend using this little tool.