SH 2 atrocious WiFi speeds at close and long distances, Full Fibre 900

[TheWhitgiftCentre]

I recently had Full Fibre 900 installed in my house, which is a 1930s 3-bed semi-detached. The walls are made of brick, but are not massively thick, and we have wooden floors throughout. Our street is run-of-the-mill residential, and our immediate neighbours are with Virgin. 

Since installation, we've had pretty much consistently fast ethernet download and upload speeds (a test just now returned 801mbps dl/97 ul, with a ping of 9). This would, I assume, indicate that there is no problem with the line. However, the WiFi speeds we are receiving are truly shocking - at 3ft away from the router in the same room, I get 40mbps. In some parts of the house (which isn't massive), I get speeds in the single digits. What's weirder is that, upon resetting the router, or tweaking some of the settings, the WiFi speeds suddenly become lightening fast (600-700 mbps dl in the same room as the router, 300-400 dl downstairs) for 5-10 minutes, before plummeting again. I have tried using a different router (ASUS RT-AX56U), but found that this only made a slight difference in speeds.

I spoke to someone at BT on the phone, who was as puzzled as I was. She reset the router remotely, and asked that I report back in a week if things haven't changed. I don't think that's good enough, given that I'm now over a week into my contract and have not received anything close to normal WiFi speeds, let alone speeds I'd expect from the Full Fibre 900 package. 

Relevant details from the technical log:

Product code: Smart Hub 2

Firmware version:v0.24.04.11017-BT

Firmware updated: Tue Feb 9 12:51:48 2021

Board version:R01

GUI version:1.71 05_06_2020

DSL uptime:0 days,01 Hours17 Mins50 Secs

Data rate:1000 Mbps / 1000 Mbps

Upstream error control:Off

Downstream error control:Off

Data sent / received:395.1 MB Uploaded  / 10.1 GB Downloaded

Broadband username:bthomehub@btbroadband.com

BT Wi-fi:Activated

2.4 GHz wireless channel:Channel: 11

5 GHz wireless channel:Channel: 44

Wireless security:WPA2 (Recommended)

Wireless mode:Mode 1

Firewall:On

Software variant:-

Boot loader:0.1.7-BT (Thu Nov 30 09:45:22 2017)

[licquorice]

If a third party router made little difference, it is clearly not a BT problem but a problem with your home environment. No ISP guarantees wifi speed as there are too many variables. Have you tried changing channels?

[TheWhitgiftCentre]

Hi - yes, I've changed the channels, which provides a 5-10 minute bump in speeds before plummeting again.

Would my home environment be the issue if the speeds are slow even when I'm stood 3ft away from the router in the same room? I wouldn't be concerned if the speeds were in the 100-200mbps range (which is considered 'slow' by some). However, we're talking regular speeds of 40mbps, and as low as 7mbps, in the same room.

[licquorice]

I guess there could be some serious interference being generated from somewhere.

Is this with just one device or multiple devices?

[TheWhitgiftCentre]

Multiple devices - two smartphones (both Android), a PS5, smart TV, and a modern laptop. The SH is in the same room as a NAS, which is connected to the SH via ethernet.