Using this wonderful thread I helped get my parents setup with 2 Actiontec's to provide internet access to their living room for their new Roku box. I actually had the boxes shipped to me where I made the setting changes and forwarded the routers to them as they are in a different state.
They got it setup (as shown in the attached diagram) and everything seemed to work fine. Lately though they have complained that the internet speeds on their computers (both wired via Ethernet directly to their Dell router and via wireless) have slowed to a crawl - but that the Roku box which is connected to the secondary Actiontec is operating fine.
I read through the thread and see that my problem has occurred for others before but there didn't seem to be a common solution.
As a test I had my father remove the coaxial line connecting the Actiontec at the cable modem/Dell router to the coaxial splitter. When this was disconnected their internet speeds went right back up to normal, so obviously something is happening with the Actiontec.
All splitters are rated 5-2400 mhz, I don't not believe there are any coaxial amps involved (though if there is that might explain the problem).
As I am trying to instruction/guide from afar I am tying to come up with different possibilities for my father to check.
What I am thinking so far:
1) Check and make sure the Actiontec's aren't serving their own DNS values out (I am pretty sure I disabled this in the settings).
All of the routers/computers, etc share 192.168.1.x ip addresses, so there hopefully shouldn't be any issues there and I don't believe there are any ip conflicts going on.
2) Verify the internet connection from the Actiontec in the living room with a laptop (to make sure it's actually working, which they claim it is with the Roku box).
3) Take the secondary Actiontec to the first Actiontec and connect them using a short coaxial cable and then verify that the Actiontec's are sending an internet signal over the short coax and also verify that the rest of the house which is hard wired via cat5e (or 6), unsure which, is working properly while the two are connected.
If #3 works for the entire house then we can surmise that there is an issue created when the ethernet signal is sent into the coaxial line by the Actiontec.
Any other thoughts or insight would be greatly appreciated.