Does a wireless extender slow down wifi speed?

My gut feeling it shouldn't but my real life experience is it does and I can't work out why.
Here's my situation. I recently changed ISP to a fttp service and was supplied with a Technicolor ac router. On my laptop and mobile I'm seeing speeds of around 375Mbps down from a different room to the router..Thinking I'd get better wifi coverage throughout the house I got a TP Link ax extender but to my dismay when I set it up my wifi speeds drop to around 250Mbps instead of the 375ish I had before, devices speed measured in the same position.The devices are using 5G channel not 2.4.
If I turn off the extender the speeds rise back to the previous level.
Anyone have any idea on what can be causing this?

In general, if the ap doesn't use its own backhaul channel or wired backhaul it will reduce wifi speed sometimes by up to 50%.

I assume you want better wifi coverage in your property?

better coverage yes.
I'm not using the device as a AP just a wireless extender.

Post deleted by ian72

You will have a much better experience purchasing a dedicated wireless access point and running a cable to it. The UniFi devices are very good, and can be managed via an app on your smartphone.

Wireless extenders are snake oil IMO, they either flat out don't work, massively cut your connection speed, introduce lag and general instability.

We have a TP powerline extender for the far end of our house, and it cuts our 70MB connection by more than half. The wifi connection to Sony TV is flaky so I use a short ethernet cable and it works fine for the past four years, unlike the Devolo gear. Soi my answer is yes, extenders do slow things down.

The Powerline committee has shut down. Powerline wasn't able to keep up with the speeds that WiFi could reach easily.

Most "extenders" work by receiving a WiFi signal, and then transmitting it on a different channel/frequency. If you pick up a 20 MHz wide 5 GHz signal and transmit on 20 MHz wide 2.4 GHz this MAY be close in performance. All other combinations will result in slower speeds.

A proper mesh system using hub/spoke topology over wired backhaul is best, but mesh systems that use WiFi as backhaul CAN work better than simple "extenders" and much easier to configure.

I use TP-Link EAP PoE AP's and they are very good. Easy to setup and manage via a browser or app on a phone. They do not interfere in any way with the Wifi speed.

I would second using a dedicated Unifi AP. They do also support wireless meshing but try to wire them over PoE for best performance.
There are some older models which are still perfectly usable (I'm using AP-pro) albeit maybe without the absolute fastest speeds but still able to work at 600mbit and are availble 2nd hand from £30 with a PoE injector. They are so simple to setup using the Unifi software too.

In reply to a post by jchamier:

The Powerline committee has shut down. Powerline wasn't able to keep up with the speeds that WiFi could reach easily.

Ahh i didn't realise that had been shut down. I have noticed a decline in new products.

In reply to a post by jchamier:

Most "extenders" work by receiving a WiFi signal, and then transmitting it on a different channel/frequency. If you pick up a 20 MHz wide 5 GHz signal and transmit on 20 MHz wide 2.4 GHz this MAY be close in performance. All other combinations will result in slower speeds.

Just gonna mention if the extender picks a congested channel to retransmit, you may find slow downs. Also, if the wireless extender only recieves say 5mbit/5mbit, then you will only have that speed regardless of the connection to the extender. I know you that you know this, just saying for the masses who may not.

In reply to a post by jchamier:

A proper mesh system using hub/spoke topology over wired backhaul is best, but mesh systems that use WiFi as backhaul CAN work better than simple "extenders" and much easier to configure.

even with a dedicated radio for wireless backhaul, you are facing the same issues that your wireless router faced. A combination of wired and wireless backhual would better but may only provide good thruput in ideal conditions - ie good wifi signal.

Yes, the 2.4GHz radio is not going to count for the purposes of the desired throughput.

If the extender only has one 5GHz radio then the speed is inherently worse than 50% due to spending at most half the airtime talking to the upstream router and half to the downstream client.

Taking the extender out, if you want more range on 5GHz you need to reduce the bandwidth of the radio to improve signal density.
Range or throughput (pick one).
Try 40MHz by default or 80MHz.

Far too many consumer devices default to 160MHz channel widths for my liking and 320MHz is just silly given the UK channel lists unless all of 6GHz gets opened up.

Currently OFCOM are consulting on policy for 6GHz for sharing with mobile operators and there have been a few notable submissions representing the case for Wi-Fi (as well as from Jodrell Bank for how not to mess up their radio astronomy).

In reply to a post by Taras:

Ahh i didn't realise that had been shut down. I have noticed a decline in new products.

The website has gone, so you have to read from the archive.org copy:
https://web.archive.org/web/20170107003919/http://ww...

Since nothing has appeared since that event in 2016, my assumption is that Homeplug as a concept was overtaken by WiFi.

There are some APs with three radios: one 5GHz for backhaul/mesh, plus 5GHz and 2.4GHz for clients.

However, you'll be better off anyway with wired connections to your APs, as has already been said.

Since AP coverage will overlap, make sure your APs are on non-overlapping channels (which in the 2.4GHz band means only using channels 1, 6 and 11)

There's a nice overview here, including the "honeycomb" pattern you can use as a starting point when covering large areas:
https://www.metageek.com/training/resources/design-d...

wackypedia(wikipedia) is suggesting that it is defunct as of 2022. Regardless of the date, homeplug is dead.

I see Metageek refers to using 4 channels in some parts of the world which makes it much easier wit an irregularr cell size and pattern. However, I am now seeing more and more UK WAPs with just 1, 6 & 11 as fixed channels

I once hada colleague who was an antenna propogation specialist who continued to do some worrk for his previous division on GSM sites. He would have a map on his desk and used 5p, 10p and 50p pieces to make his primary estimates of locations and power levels.

Edited by MHC (Tue 30-Jul-24 10:05:51)

In reply to a post by candlerb:

There are some APs with three radios: one 5GHz for backhaul/mesh, plus 5GHz and 2.4GHz for clients. However, you'll be better off anyway with wired connections to your APs, as has already been said.

Always better with separate radios, and if you have the ability to run cable then that always wins; but domestically not always an option.

There's a nice overview here, including the "honeycomb" pattern you can use as a starting point when covering large areas: https://www.metageek.com/training/resources/design-d...

Some higher end vendors have some good planning tools too. I saw some of the serious enterprise WiFi tools from Cisco from a customer years ago, but its not affordable for home users (many tens of thousands).

In reply to a post by jchamier:

In reply to a post by candlerb:

There are some APs with three radios: one 5GHz for backhaul/mesh, plus 5GHz and 2.4GHz for clients. However, you'll be better off anyway with wired connections to your APs, as has already been said.

Always better with separate radios, and if you have the ability to run cable then that always wins; but domestically not always an option.

my fibre run is currently delayed due to the heat, as i will be wearing a mask to lay the conduit because i will be kneel moving over loft insulation which is 30+ years old ... the awful powerline bridge can stay in situ for a bit longer.