Extremely slow upload speed (0.5 Mbps) and some T3 time-out error logs.
My home internet started to experience slowness when on videoconference or uploading pic/files about a week ago. The download speed is normal though. An agent from Xfinity came to my house and checked the signal. He ruled out the problems from cables, and said the upstream power is too low (< 45dBmV), and suggested me to upgrade my modem (Arris sb6183). I then got the new one (SB8200) and still got the same low upload speed issue. So I don't think the problem is the modem. I have spoken to at least 3 specialists and all of them have no idea what's going on. The only useful info I heard is all said they receive no or weak signals from my apartment.
Here are some upstream info.
Upstream Bonded Channels
|Channel||Channel ID||Lock Status||US Channel Type||Frequency||Width||Power|
|1||3||Locked||SC-QAM Upstream||30300000 Hz||6400000 Hz||43.0 dBmV|
|2||1||Locked||SC-QAM Upstream||17300000 Hz||6400000 Hz||43.0 dBmV|
|3||2||Locked||SC-QAM Upstream||23700000 Hz||6400000 Hz||43.0 dBmV|
|4||4||Locked||SC-QAM Upstream||36700000 Hz||6400000 Hz||43.0 dBmV|