Damn. I have no patient with slow Internet speed. It's killing me when the website is buffering. Too bad that CentryLink in my area can only offer up to 20MB download and 800K Upload. I also have the old Linksys WRT54G 2.4GHz wireless router.
Recently, I notice my evening Internet speed wend down from normal 16MB download to only 1MB or slower. It's killing me and I can't watch YouTube on my SmartTV. So troubleshooting begins. After many test and configuration changes, I think my 2.4GHz cordless phone isn't the main cause of the slow Internet.
If I wired my laptop with the router, I can truly get 16MB connection, while my wireless connection is still only 1-4MB. After searching on Google and made the following configuration. I can now getting 9MB-16MB wireless connection in most of the time. That's much better than before.
I also think my cellphone Nexus5 with wireless connection is interfere with my Laptop wireless connection.
Here is the screenshot of my wireless configuration on Linksys WRT54G router.