I recently had cause to reconnect a wi-fi extender - the TL-WA850RE - to my Smart Hub. I plugged in the extender next to the router, pressed the WPS button, and made the connection. The extender webpage showed showed the signal received as 100% but the wireless rate to the router as 144.4Mbps. I was surprised at this low rate as the Smart Hub specification advertises a 290 Mbps max throughput.
As a comparison, I then tried the same test with a TP-Link VR900 V2 which should have the same throughput on 2.4ghz as the Smart Hub. When I connected the range extender to the VR900 V2, it's webpage showed a wireless rate of 300Mbps - which is what I would have expected in view of the router's specification. I expected the same for the Smart Hub.
All this suggests to me that my Smart Hub is operating nowhere near to its speed specification on 2.4ghz.
Has anyone else found this? Is my Smart Hub defective in this respect?
I think you will find that the max throughput is defined as the sum of transmit and receive. 145*2=290.
Also bear in mind that a range extender will reduce the throughput, as each packet of data has to be received, buffered, and then re-transmitted on the same channel.
Its much better to use a proper wireless access point cabled to the home hub, or use a broadband extender with a wireless hotspot, like this.
The BT Smart Hub test report states that the 290 Mbps data rate achieved on the Smart Hub (HH6) at 2.4 GHz with a 3x3 antenna uses 256-QAM (but only a 20 MHz wide channel, otherwise it would go up to 600 Mbps).
256-QAM (or Turbo-QAM) is used as standard on 5 GHz band with 802.11ac, hence the speed increase of 11ac over 11n, but there are very few client systems which support 256-QAM on 2.4 GHz band because this is not compliant with the 802.11n spec and is regarded as a proprietary extension (for now at least). AC is 5 MHz only. It is a bit misleading of BT not to emphasise this in their test report.
Although BT and a number of OEM wireless routers support 256-QAM on 2.4 GHz band, this is currently mostly a marketing gimmick as it allows them to advertise as capable of 600 or 900 Mbps for 2.4 GHz wireless-n. Unless you have a client adapter which also supports 256-QAM, the most you will get from the HH6 on 2.4 GHz will be 144.4 Mbps because the HH6 is restricted to using only a 20 MHz channel width. Other routers without 256-QAM can go up to 300 Mbps using a 40 MHz wide channel but this is often unachievable in practice due to interference from/with neighbouring wireless networks.
See this discussion for more details: HH6 and 2.4 GHz Wireless N speed issue
Thanks. That might explain the difference I found between the Smart Hub and TP-Link VR900 which have apparently similar specifications.