@Tonting, answer this, where the backhaul is AP-1 & AP-2 1-Both connected by its POE, or using one POE, and POE passthrough to the second one 2-what's the separation between APs, minimum 3 meters...

You will only use those 3 chs for all your 72s Make sure you don't use the same to the one close to In this case the ones upstairs use the same 3 channels Your deploy is wrong, having three 72s apart...

20 mts. is that the distance you need or that's a test Distance is too close for 5210 Change value to indoor or change value to 0.22

and you think this is a Guessing Game DISTANCE of the link

handsome wrote The access points are configured to be on the same channel wrong, they have to be in dif. channels, use 1,6 & 11 the closest AP to another has to use a Dif channel you chose the wrong...

You have to decide, are you setting AP or Repeater Those are two very dif. setting, Repeater works wireless AP works cabled to main router Both provide, wireless connection to your IOS devices...