Wireless Joint

I receive home internet from AT&T through a Netgear 1100. When I reboot the 1100 signal strength goes to 3-4 bars then after a few it drops to 1-2 bars. Why doesn’t it stay at the strongest signal? 1100 is mounted on a window. I have moved it to every location within the house and there is no st...

I use a Netgear 1100 for home WiFi. Using AT&T. On reboot the signal strength is three to four bars then after a minute it falls to one or two bars. Why does this happen? Thanks for your input.