Speed Dropping to below 1Mbps

[#1]

This has been happening for quite a while now.
Sometimes I will test the speed and it will come up with 10-12Mbps. Perfect. But lately it will just drop down to anything as low as 0.1Mbps without warning, and suddenly rise back up and then back down again.

I don't really know what the problem is and it seems neither does Plusnet.
They sent someone from Open reach out to have a look at the Master Socket, which didn't help, the problem persisted.

I phoned again and they told me that the speeds from outside to my router are spot on and then told me to change WiFi channels, which does actually help when one drops to unusable speeds, but it's only a quick fix and within the next couple of days, it will only drop again and I will have to change WiFi channels again.

It is very irritating watching catchup TV for it to stop and buffer for minutes at a time before the speed rises again. (for it to then drop again).

Has anyone else had this problem? If so, what is actually wrong and is there a solution?

Thanks.

[#2]

Welcome to the forum.

I'm assuming that you are using a Plusnet Hub Zero. If your speed is OK with a wired Ethernet cable then it's most likely due to the known poor wireless performance of these routers. 

The best way to find the best wireless channel is to use a wifi sniffer app, I use Wifi Analyser on an Android phone. With this you can see all your neighbours competing transmissions. Check both where your router is situated and where you use your wireless devices. Note the quitest channel. Then log into your router and select the advanced wireless settings. Here you can manually select the best channel.

If you are prepared to set up a router yourself that has far superior wireless performance then go onto Ebay and get a BT Smarthub 6.  They are going very cheaply at the moment. You will find the setting instructions in this forum, plus of course there's help available here if you have problems.

[#3]

Thank you for the reply.

Yes, that's the one! I would never have guessed the problem would be with the router itself!?
We were debating switching to fibre to see if that would help but Plusnet said that the speed to the router is apparently okay. We also thought about switching providers, but didn't want to risk it if the problems still occurred with another provider then it would have been a waste of time.

I will definitely download the app you suggested and also have a look at the BT Smarthub too.
Thanks for your help and advice!