TV With WiFi Cutting Out

I have panoramic WiFi modem "Technicolor" and two 'sandwich-sized" receivers. One receiver is next to the modem and the second in living room perhaps 25 feet away. Having recent troubles with both TV's experiencing "cut-out" where the video and/or audio stops for 2-10 seconds, then resumes. This occurs - too often -  with both recorded and live shows. In addition, the fast forward on the living room TV can be VERY slow engage and also. inaccurate: freezes instead of fast forwarding, then either stops early or late. At times, have to go to FF-3 to get it started. Icon shows 2 out of 3 'arches' for signal strength, but has shown that since I received the system over one year ago. The cut-outs began perhaps one month ago. I have sent a signal thru both the receiver and modem - from my computer - with no joy. Any ideas? Thanks.