Multiple access points, poor WiFi

[2Btoo]

I'm having a problem with home WiFi. The set-up is thus;

- House is a Victorian affair on three floors (Basement, Ground and First) with solid internal walls
- Telephone line comes to my office (back of the house, first floor)
- Router (TP-Link) connects to telephone line in my office and to main computer (with networked drives holding films, music etc). This router has WiFi on and a DHCP server running, on Channel 9 (one of the quiet ones locally)
- Hardwired ethernet cable connects from router to a second router in the middle of the house (old Netgear DG934g). This is in the middle of the ground floor, in the centre of the house. This router has DHCP turned off, is only plugged into the ethernet cable, has WiFi turned on with the same SSID and password as the TP-Link router but is on channel 4 (another quiet one).

This seems to me like a logical arrangement that should give good WiFi coverage to the whole house - the TP-Link router can't reach the front of the house from my study which is why I put the second device in. Having the same SSID and password on the two routers should give devices the ability to move from one router (or 'WiFi access point') to the other seamlessly. However it doesn't seem to work like this; devices sometimes seem to hang on to the further router if you walk around the house with them and if you walk from one end of the house to the other they can show a weak signal when stood next to a router.

It is a particular problem with a Chromecast Audio we have just purchased; while playing to this device my mobile will apparently 'lose sight' of it, meaning that the playback stops at the end of a song until the 'phone is given a prod to re-connect. This is annoying. (For reference, the 'phone is an old Moto G, but other devices seem to have similar problems. 'Other Devices' include my wife's Moto E, a Nexus tablet and three or four laptops all running Linux distros.)

As an experiment, I have just turned off the WiFi on the TP-Link router upstairs so there is only one WiFi point in the centre of the house.
And this seems to have improved things; the devices all show the sort of level of signal you'd expect given where they are located and the Chromecast will carry on from song to song even when you walk around the house with the 'phone in your hand (or pocket). The downside is that I now have very weak WiFi signal at the ends of the house - particularly in my study and down at the front of the basement.

I am assuming the problem is that devices won't move from a WiFi point to another. Is this a fair assumption? If so, how do I make them more keen to move over, and will this cure the Chromecast problem?

All help welcomed - thanks. Do ask if any part of the explanation isn't clear!

[2Btoo]

Thanks for your help. I've done some googling and it seems that consumer-grade kit simply doesn't work that well in this sort of set-up and the solution is, as you say, better kit with a central controller.

Davepoth, yes, the Netgear thing is old (but was supposed to be good in it's day!) The TP-Link is a TD-W8960N, which isn't new either but isn't as old as the Netgear device.

I guess I am probably just expecting too much from the kit I have.

Yes, a better device in the centre of the house would be a good idea but the telephone line is at the top and back of the house. I guess I could put in a telephone extension but it would be a faff!

Thanks again for your help.

[2Btoo]

Thanks for your answers. The reason I chose the channels I did was that they are by far the least congested ones 'round here. I could have chosen ones with greater separation but then they would have been sharing with a number of other WiFi networks.

As it is, I think the simplest solution is to carry on with the single access point in the centre of the house on and the WiFi on one in my study off (i.e. use it just as a Modem and router, not as a WiFi access point as well). It's been like this for a few days now and, while the price to pay is weaker signal at the ends of the house it does mean that the Chromecast works as it should. It seems that in this instance I can't have my cake and eat it (or at least, not without buying one of the ubiquiti solutions). Shame, but there we are ...

An alternative configuration would be to put the better router (the TP-Link one) in the centre of the house and use the older Netgear item in my study. However this would mean that I'd be using the Netgear as the modem, and may lose some speed. Perhaps I should experiment with that a little!

Thanks for your help.