@c1111 it would be very rare to get 900Mb/s over wifi apart from the room the hub is in. Wifi signals lose power when passing through walls the denser the wall the greater the loss 60Mb/s is quite likely in a room where the signal has passed through several walls. However 60Mb/s is roughly double the bandwidth required tostream UHD TV so the issue is probably the signal being affected by interference.
Poor WiFi coverage is probably the most common question we get in the forum. In many homes a single Sky hub cannot provide a usable wifi signal in every room due to the layout and type of construction of the property especially in older homes. Assuming the hub is in the best possible position which is out in the open on a surfsce then the only answer is additional wifi sources.
Your choice.is to either buy Sky's add-on WiFi Max bundle which can supply up to 3 extenders see https://www.sky.com/help/articles/sky-wifi-max or buy your own wifi system and use that instead of the Sky hub's WiFi.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
