WIFI speeds after Ultrafast upgrade with BT Smart Hub 2

Started a seperate thread as although related to my last post, it's off topic.

On Monday we were fortunate enough to complete our upgrade to BT Ultrafast Fibre 1 with a swift visit from an Openreach engineer.

All good, we are just over 100m from the cabinet and the stats on the router are showing a healthy -

Maximum Data Rate - 74.448 Mbps / 288.800 Mbps (settled down from 305 Mbps initially)
Data Rate - 29.431 Mbps / 159.059 Mbps

My PC is connected via a LAN and when I do a speed test (tried a few different sites as well as this one) I'm getting 28/29 Mbps / 138/141 Mbps

The first 2 times I did a speed test using my Google Pixel 2XL phone (within minutes of the engineer leaving) I got 30 Mbps / 140 Mbps, but ever since I can only get download speeds varying in the range 85 - 110 max (and I'm in the same room as the hub)

Tried on an Android tablet and an iPad Pro and getting the same results.

Can any technicaly knowledgable folks shine a light in to ant possible causes?

I have a feeling that the Smarthub 2 might have installed itself a firmware update after my first two tests that returned results of 140 Mbps.

I presume that it is because of the mesh network support that this hub offers over our previous Smarthub 1, but it's a bit of a pain that I now can not separate out manually devices on to the two different 2.4 & 5.8 GHz networks.

Some of my devices that I previously had connected to 5.8 for faster transfer have connected to 2.4 GHz and I can't find any way of manually overiding this.

Any suggestions greatfully received - Thanks in advance

1. What download speed did BT say that your connection was good for when you signed up?

2. You should be able to get that speed using a gigabit wired connection. This websites speed test would be fast enough - IME.

3. Speed tests using wifi are quite possibly unreliable for the speed that you router connects at. You would be lucky to get a third of the wifi connection speed.

Thanks for your reply Michael,

I'm getting higher than the quoted range for both upload and download by a few Mbps on my LAN connected PC using several speedtest websites and have also downloaded and installed the Speedtest.net app onto my PC

The confusing part is I did get 140 Mbps twice over WIFI on my phone directly after the line was connected.

I beleive my phone has a 2x2 wifi module and when I look in the WIFI settings it is showing as a "Transmit link speed of 866 Mbps", so surely the 140 should be obtainable all the time with ease?

When it comes to Wifi, data transfer rates are more like a quarter or maybe a third of the connection speed and that is with no interference, particularly from other wifi networks.

Most likely devices are trying to use 2.4 GHz and the wider frequency bands which are great if no other wireless networks are in range, but once you get overlapping networks you very quickly lose throughput speeds.

In reply to a post by Michael_Chare:

When it comes to Wifi, data transfer rates are more like a quarter or maybe a third of the connection speed and that is with no interference, particularly from other wifi networks.

Not quite as simple as that. 2.4GHz with 20mhz wide channels is often constrained due to interference. However with 5GHz, and with 40mhz or 80mhz wide channels, I have friends with 200 Mbps easily from their Virgin Media service - over WiFi. (NB: they don't use the VM SuperHub for the WiFi)