Signal Dropping w/Comcast Modem as Bridge and Netgear R7000?

I have an ARRIS / Motorola SURFboard SBG6580.  I also have a Netgear R7000 Nighthawk with DD-WRT firmware installed.  What I want to do is have the modem act as a simple bridge and use the wireless signal from the router, ignoring the wireless signal given off by the modem.  However, when I try to connect to either the 2.4 GHz or 5 GHz signals the router provides, it drops about every 20 minutes.  Anyone know how to remedy this or what might be going wrong?

Also of note, the router's signal never dropped before I replaced the modem a month ago.

#d6bad0;">

Maybe your router and your ComCrap box are using the same channel? Try setting the channel to manual on both and setting them differently.