Thanks this worked for me. Now i am facing other Problem. On 2,4ghz the speed is very slow, it is set to Auto channel. My router is high placed and not near/behind the TV . On 5ghz i got my Isp speed on 2,4ghz it is cut , just 50% of what i should have to got.
It tried it, there is no difference on 20hz, again slow on 2,4ghz. Why is it better to stay on 20hz? Could you explain a little bit and do you got another solution for me?