Ive been having this issue for a few weeks now, it got to the point where I had the router replaced and it made the issues less frequent but even with the new router it still randomly lose connection requireing a full restart of the router.
Here's what I have connected via ethernet cable:
2 Desktops
1 PlayStation 3
1 Xbox 360
Via wireless
3 laptops
2 Cell Phones
1 3DS
These aren't all connected at once because that would be crazy. Even when it's just me on my desktop reading news while netflix on my Xbox 360 plays in the background, and a relative using a laptop it'll still cut out and it's really aggravating.
All the coaxial connections in my home are fine.
The router is an Actiontec MI424-WR Rev F. I think the one I replaced was too.