You can't have two coax WAN connections. If you try that the two routers will fight each other for the single WAN DHCP lease.
Use the »Verizon Online FiOS FAQ
»Can I get an ethernet connection in a room with only coax?
instructions that birdfeedr
linked earlier. They allow you to connect both Actiontecs to the coax, but will disable the WAN connection on the second router. The two Actiontecs will be connected LAN-to-LAN. The second Actiontec becomes a MOCA LAN bridge, a switch and a WAP.--
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