Routers / Switches :: Put A Wireless Computing Behind Another One?

I am trying to put a wireless router behind another router. I have DHCP on the wireless router disabled and connected wireless router LAN port to wired router LAN port. The wired ports on the wireless router work fine. The wireless signal strength is good and shows a good connection. But wireless connectivity to the internet is poor. Ping to the main router shows most packets are lost. I have assigned the wireless router an address outside the DHCP range but in the same group. Main router is 192.168.15.1, wireless is 192.168.15.2, DHCP range is 192.168.15.100 to 192.168.15.130. I though the router might be bad as it is an older one so I got a new one - same issue.Update - found the problem. The wireless on the old router was still connected and running. Had some trouble getting wireless turned off for it. First speedtest.net run on new wireless showed low download speed (0.35 Mbps) but later showed same as wired (1.3Mbps). Not sure why the first test was so low as I have tested several times and now get the higher number. The old router (DI-524) even seems to display its web interface slowly although the wired ports still seem to work ok at least LAN to LAN.