Verizon FiOS → Wireless Signal from Actiontech Having Weird Problems

Strange happenings with my Actiontech router (Rev. I) starting yesterday and I'm unable to find a solution. Yesterday afternoon, the wireless signal became very sluggish. I'm talking down to about 10-12 from it's usual 50-54. I have an Airport Extreme in "bridge mode" connected to the Actiontech and it was making the strangest noise during this issue. When I disconnected it from the Actiontech, the noise stopped. Came downstairs and noticed the wireless signal icon on the Actiontech was blinking crazily.

So I rebooted the ONT, routers, computers hoping it would clear up, but no dice. Started disconnecting ethernet cables from both routers, still wasn't fixing anything. Last gasp attempt I went into the Actiontech settings and disabled wireless - and that was the trick. The Airport Extreme went back to normal speeds. Enabled wireless on the Actiontech again and the same problem occurred. (FYI - speeds were completely normal when hard-wired to the Actiontech, even as this was happening.)

So, anybody have any thoughts what that's all about? I need to have the wireless signal active from the Actiontech, as it serves our basement wi-fi needs. Wanted to check here before - GULP - giving Verizon a call to see if they'll send me a new router, if that's indeed what the problem is. Thanks in advance.

Try setting the actiontec to use a specific channel. Use inSSIDer to find a channel that is not congested. Maybe you are getting interference from a cordless phone or someone else's router.

What's the reason you "bridge" the airport extreme instead of using it as an AP?

Maybe things have changed since I originally set this up a few years back, but that was the only way the AE would work properly in my setup - hardwired to the Actiontech and put in "bridge mode." (I need the Actiontech at the front because I have FiOS TV also.)

Will give that a shot marc. Thanks. Though don't know why that would suddenly happen after over two years of no interference.

Yes, if AE's signal is strong enough for the whole house just turnoff AT's wireless you will have zero interference between the two radios. From my understanding, bridge mode will cut your speed in half anyway. Your TV's will be fine as long as you leave the Actiontec doing the DHCP/routing. You need to disable the DHCP server/firewall/NAT in the AE manually to use it for AP only or the AE's web management might have "access Point mode" just enable it and it'll do the rest for you. Then you are ready to connect the AE's LAN port to AT's LAN port through an ethernet cable.
Your interferences might have caused by neighbors that just started to use channels overlapping yours.