First some background information – you can skip this if you want.
internet) enters your house. If you’re lucky you will have a fibre-optic connection which would give you the fastest speed and performance but the fibre only runs from the Exchange to a Street cabinet. From the cabinet to your house the connection will be by copper. You can 
recognise whether you have fibre in your area by looking at the BT street cabinets. If they’re like the one on the left – you have. If they’re smaller like the one on the right of this picture and don’t have vents in them (necessary for cooling) – then you won’t … yet! Inside the cabinet it is still likely that there will be a tidy arrangement 
of cables and patch leads – not at all like the old telephone street cabinets which usually are rather untidy. So the picture to the left is a couple of rather proud BT engineers looking at a new fibre cabinet. So whether you have copper or fibre to the cabinet, the connection to the broadband in your house will be by copper. This is the same for the cable operators like Virgin Media as well.Your broadband provider (your Internet Service Provider, or ISP) will have given you a device that presents the internet into your house. This could be done in a number of ways, but for this discussion I will call the device a hub. The hub incorporates two components – a modem which pulls the signal from the street cabinet and pushes a signal back, which in turn is connected to a router which handles the distribution of the signal to your various devices in the house. Sometimes these are two separate devices, in the case we’re considering they are one and the same. Your router will probably itself have two components – an aerial for sending and receiving a WiFi signal and a number of ethernet ports to allow you to directly connect a device by an ethernet cable to the router.
[This is always faster and more reliable than using a WiFi connection – but more about that later.] In the diagram to the right the WiFi is being delivered from a separate Wireless Access Point. This is not the normal way of providing Home WiFi nowadays, but before the introduction of “the hub” – it was.
Every device connected to the internet has an IP address, some are Public, some are Private. Almost certainly all the IP addresses in your house, behind the router will have Private IP addresses. Your ISP will dynamically allocate an IP Address to your router when it sees it’s switched-on, ready for connection. This will be from a store of addresses it has and will look something like this – 86.10.6.1 – this is effectively the equivalent of the telephone number for your house. As the number of Public IP addresses is limited, your router will then allocate an IP address to each device from a Private range and these will look something like this – 10.0.1.2. It is the job of the router to map the devices from the Private range of IP addresses to the Public IP address space of the Internet.
So you can see I hope that the Router is a really important piece of equipment as it handles all the transfers of information to and from the internet using IP addresses. If you’re using wired ethernet connections that’s really all you need to know (there’s loads more but not for this post) and as long as your hub is working and has the correct lights shining all should be well. However we have the wireless network to consider, don’t we? So now we come to “flaky WiFi”. At last, I hear you say!!
Your wireless router (or hub) broadcasts signals to devices on different channels (like TV channels). Usually when you switch it on it will configure itself to use the best available one. However, if another network nearby (say next door) is using the same channel there will be interference between the two causing the signal to be interrupted, the information to be resent, the performance to drop. This is the most common reason why you will get “flaky WiFi”. Other reasons may be that you are too far away from the wireless router to get a good signal, you’re moving about, the walls are too thick, the router is not located in the best position to cover the whole house, the wireless card in your computer is damaged in some way (or is just too old to get good performance), or your software is not configured correctly.
I can’t deal with all of these but here are a few links that you may wish to follow up these …
For the Mac user – Lost WiFi: How to fix WiFi connection problems.
… for now I’ll just go through a couple of situations.
1) If the signal as shown on your device gets stronger the nearer you get to the router, your problem is likely to be the siting of the router. You need to move it closer to where you wish to use the device, or consider a wired connection instead. This might sound daunting, running cables and the like, but you can buy a pair of Powerline plugs and connect the router to the device using your internal mains electric circuit. Alternatively, you could extend your network, again using Powerline technology to provide a Wireless Access Point near to where you want use your laptop, phone or tablet. [Note: There are other manufacturers and suppliers of this technology other than Trendnet and Amazon, this is just the kit I use. Furthermore {Feb 2021} the use of Mesh systems has become more common.]
2) If the WiFi is definitely “flaky”, it’s intermittent, or undependable, you’re most likely to need to change the channel. You may be able to do this yourself using the management software provided for your hub, but you may also find it better to contact your ISP, explain your problem, say that you believe you may need to change the channel and they’ll talk you through doing just that. [They may indeed be able to change it remotely.]
That’s it. I knew about channels before writing this, but not the term “flaky WiFi”. I’ve learnt something new!
PS If you want to know just how well your device, and/or network is performing why not use Speedtest, it’s available for mobile devices like phones and tablets as well from the App Store or Android Store. Here’s a screenshot of a test I just did on a wired connection in my house using Virgin Media as my ISP. It’s quite addictive.