Competent networking n00b needs help troubleshooting bad internet connection

[BlackJack10]

Title says it all. First, hardware specs:

Comcast TC8305C Cable Modem
Dlink DIR-605L Wireless Router
Dlink DWA-130 Wireless USB Adapter

Everything is over good quality Coax and Cat5e cable. Distance between the router and adapter is about 35ft. Adapter is 20ft above the Router, if that makes any difference.

For the last 4 months we've had the system, my connection has been just fine. 10-20ms ping, about 10-15/4 mbps. For about the past week now I've been having some issues. Online games are dropping and disconnecting rather frequently, and if it doesnt disconnect the gameplay itself is absolutely horrid. Web browsing is slower, downloads are taking longer, etc. Ran speedtest again, still says I have a good connection. I've noticed that when I've been playing games my total usage has been somewhere in the area of 10-30/500+ kbps. I can upload things just fine, but my download is absolute crap.

Where should I start as far as troubleshooting? Any ideas as to what is going wrong? As always, thanks in advance.

 

[Psyko07]

I would try resetting everything first, unplug your modem and router wait a few minutes (3-5) then power the modem up let it establish a connection before you power on your router. You haven't added a cable splitter or changed your coaxial in any way?

 

[BlackJack10]

Tried resetting it, that's always the first step. Network hasn't been changed in months, so I highly doubt that's the problem. There is a splitter that splits the coax to the modem and to the TV box itself, but that's been there ever since we got the modem.

 

[Psyko07]

Open up a web browser and got to 192.168.100.1 that should be your cable modems config page find the signal strengths for your downstream and upstream channels post the findings.

 

[BlackJack10]

Sorry, but my dad is being an *** and won't let me in. He thinks that my computer should automatically work just fine and that overclocking and modding and such is ruining my computer, so he won't let me mess with the modem. I'm 15 and his "computer buddies" have told him that I know what I'm doing and to just let me do it, yet he still restricts me. -sigh- [/rant]

I still have access to the router, if that's of any use. Also, my connection is kinda sorta back, but I want to make sure it doesn't happen again. Anything I can do about it now?

 

[Psyko07]

Just got to that IP address on your computer it will not let you change anything just view the signal strengths for your downstream and upstream channels. This will let you see if there is a problem with the cable line which your cable company would most likely have to fix.

You may want to look at your cable splitter most splitters will put the signal loss on the outputs make sure your modem is connected to the lower of the two your cable box is not near as sensitive poor signal strength.

 

[BlackJack10]

The IP you gave me wouldn't work, so I went and found the one for Comcast Modems. I have to log in to view anything. Unless there's something I'm missing?

I'll take a look at the splitter itself later, see if switching anything around would help.

 

[Psyko07]

If you have to log in they must have it locked down you could call them and ask them to check the signal strength on the modem for you and see how that goes.

Edit: That modem looks like a router modem combo... I bet you username: admin password: password will let you in

 

[BlackJack10]

It is. Admin login/pass is exactly what I don't have, sadly. I'll try calling them, hopefully it'll go well.