I bought the device in subject to extend the range of my WPA2/PSK-protected wifi network powered by a TP-Link TL-WR340G device (AP+router).

I configured it as follows:

• Operation mode: Universal Repeater
• MAC of AP: scanned my SSID and got it
• Channel width: 20MHz
• Security options: the same as the parent AP (WPA2/PSK with AES encryption)

After configuration inSSIDer shows me two APs beaconing the same SSID at different SNRs (because I was with my laptop close to the extender). After a few hours my tablet, far from the parent AP, stopped working. I found that the scan reported two networks with the same SSID: one WPA-protected and one free at all. This happened very frequently. Rebooting the extender by unplugging it worked but this doesn't last long.

Sometimes the extender stops transmitting at all, sometimes it beacons an open network to which nobody can connect (because there is no DHCP).

What's wrong with my configuration?