changing channels on wi-fi

I am confused, I know it don't take much, but that is not the point.
I am using at the moment a Plusnet sagem router, I decided a couple of days ago to change the channels from auto to 6 as according to Wi-fi analyser on my phone it was the best channel. It worked fine for a hour and then both my phone and my tablet lost connection and would not connect again, so I changed the router back to Auto and all was well.
So why on earth would changing the channel to 6 make a difference?

Maybe when using the fixed channel some interference comes and goes causing intermittent problems

My Dell laptop has a Dell utility which shows the strength of all the visible wifi networks. It would quite probably be useful for helping to solve the OPs problem. There are comparable Android apps.

Same goes for MacBook Pro laptops. The 'Wireless Diagnostics' app allows you to scan all wireless networks in range and see what channel they're on and what the signal strengths are. Having said that, allowing automatic channel selection seems to work for me.

I've got the free Technicolour router that came with the fibre modem. I'm on the 76Mb service from Plusnet. I can almost get that max speed by using an ethernet cable. But as I've posted before, the wifi speeds go up and down a lot. Does anyone know if the automatic channel selection picks the best channel once or does it regularly change the channel depending on the conditions?

I find that the automatic channel starts off fine and then the speed drops a lot and I have to use manual channel selection to get a good speed. This afternoon I was getting 40+Mb on the wifi, then it just dropped to about 2Mb and I manually changed channel to get it back up to about 30Mb. This happens a lot.

In reply to a post by MrSaffron:

Maybe when using the fixed channel some interference comes and goes causing intermittent problems

I thought that, I may try another channel, but even nmow my phone still says that channel 6 is the best one.

The one my router chooses which is channel one seems to be the most congested.

In reply to a post by greenwich:

I've got the free Technicolour router that came with the fibre modem. I'm on the 76Mb service from Plusnet. I can almost get that max speed by using an ethernet cable. But as I've posted before, the wifi speeds go up and down a lot. Does anyone know if the automatic channel selection picks the best channel once or does it regularly change the channel depending on the conditions?

I find that the automatic channel starts off fine and then the speed drops a lot and I have to use manual channel selection to get a good speed. This afternoon I was getting 40+Mb on the wifi, then it just dropped to about 2Mb and I manually changed channel to get it back up to about 30Mb. This happens a lot.

Most routers i have looked at seems to stick on Channel one, it is as if that is the only channel available.

I am still looking at a new router, but then the cost of it puts me off.

Congestion occurs, when numerous Wi-Fi routers in the vicinity are using the same or adjacent channels. Automatic channel selection is supposed to avoid this problem but sometimes, the problem is unavoidable, if there are too many active WiFi connections in the area.

If are using a Windows computer, you could install Xirrus Wi-Fi Inspector, which providse details of all WiFi networks within range, together with the channel numbers.

Also the various apps only usually show what wifi channels are in use - they don't show what other interference there may be within that frequency. So, there may be no wireless networks on channel 6 but there could be other noise sources within that frequency band that are killing wifi (could also be why no-one appears to be using channel 6 because it has interference).