Long time since I did it as a matter of interest, following guidance given in CableForum and then scribbled down onto my paper notes - but my recollection goes as follows:
1/ Connect your spare SH by Ethernet to a PC/Laptop. Best not to be online to the other SH when doing this. In the background, the spare SH will be crying out via the arrow light for its DOCSIS connection. Ignore that.
2/ Go into the spare SH GUI settings (192.168.0.1) and turn off all Firewall functions.
3/ In the GUI, set up your wireless SSIDs and behaviours as you would want them to be. Consider keeping a common WiFi password across the wireless estate.
4/ In the GUI, turn DHCP OFF. Set the LAN IP address of the spare SH to be 192.168.0.254. IIRC, there is a quirk whereby you need to set the ending IP address as well to something silly like 192.168.0.253. Comeback to us if there is a difficulty when you do this. Apply the changes. While the spare SH is faffing with the changes, your connection to it will be disrupted and the spare SH will still be frantically looking for DOCSIS! When that settles down, switch the spare SH off and disconnect from it.
5/ Now connect your laptop/pc into the main SH (which is still connected to the Internet) and set the ending IP address to 192.168.0.253 (if not already so). Apply the setting.
6/ Connect a LAN port on the spare SH to a LAN port on the main SH. You can do this by direct Ethernet cable or Powerline if the AP is going into another room.
7/ Switch the spare SH on and it should work straight away. It will be GUI accessible via 192.168.0.254.
You turn DHCP off in the spare SH so as to avoid double NATting.
Me, I would use a different SSID so that I knew where I stood. Others may disagree and would say that using the same SSID allows you to pass from one node to the other. You could only check this by seeing if the "basrs" stay high.
Thanks for all the help guys, circumstances at home have stopped me progressing to date. but will follow this asap and let you know :-) I currently have a Dlink connected to my original Super Hub and used as an access point on a different ssid. it works but acts as if it is a separate router. I did have this on the same ssid and channel as the original super hub, this acted as a single system and aided roaming around the house. the Dlink access point is lost as a visible router I guess it becomes a splitter of sorts.
The detailed instructions worked without any problems for me so thanks very much.
I know have the superhub 3 (which seems to provide better wifi than SH 2ac) located in the middle of my large detached property and the SH 2 has been set up as an Access Point and located in my lounge where most of us sit and and receiving very good signal/speed - 70-100mbps on 2.4mhz/5mhz.
Thanks for the advice here. I've been directed to this thread to ask for help.
I'm having trouble getting this to work. I seem to be having an issue when changing the IP of each Super Hub. I'm finding that when I change the IP address I can no longer access either Super Hub GUI through the new IP address and I lose internet through the main router.
Hard resetting the router main router back to default settings restores the internet but I can't set up the access point.
Apologies, I misunderstood point 4. It's all working now!
Just in case anyone else makes the same point, for clarity on point 4 this is what you need to do:
"On the router you are usinsg as the access point, set the lan IP address to 192.168.0.254, set the ending IP address to 192.168.0.253 and set DHCP Server to No. You need to set the ending IP address as well or it will complain, even though DHCP is switched off."