Terrible quality of the wi-fi at the second floor (low speed + packet loss)
I need your help and suggestions about my problem. I have a 60Mbps Download / 30Mbps Upload ADSL Connection, from Live Tim ISP, very well known here in Brazil. I used to use their wi-fi router, but the signal strenght was weak on the second floor, so I purchased the Archer C60 hoping it would increase signal distribution in the whole house.
I configured the first router in bridge mode, and after it, the C60. So on, it was perfect, and we could connect 10 devices without any problem, all of them working perfectly even in the second floor.
After some time, we had a problem with the ISP, and stayed 1 month without connection, and after the repair, the internet was back, but then the problem started. I had to configure everything from the beginning, just as I did the first time. But now, internet in the second floor is pretty bad, being almost impossible to use wifi to download something heavy, or to stream, have meetings at zoom, or play online in the PS4. Wi-fi in the first floor is perfect, and works flawlessly with the full contracted speed (60 Down / 30 Up) and with everybody connected, but at the second floor, I can only get around 20~25 Down and 20~30 Up (only with 1 person connected), but with an enormous packet loss. When I check Zoom's statistics, I see sometimes 30% of packet loss, getting at even 80% during some peaks. If 2 or more people are connected at the same time, looks that all the bandwidth goes away and even opening a page at google takes a long time. Using cables, all that I connect goes 60/30 without any problem, and 0 packet loss.
I would like to know what else can I do, as I already tried changing DNS settings, changing the wi-fi channel, using 40MHz bandwidth, changing wi-fi transmission level to High... and none seems to work well...
And if someone would ask... If take C60 out of the system, ISP's router works just as it should, just with the low signal strenght that I related in the beginning.
Thank you very much!