I'm using Netgear N300 WiFi Range Extender and it is connected with CAT6 LAN cable to the main router. Even after using CAT6 LAN cable between router and extender, the speed on extender reduces to half. LAN cable is about 50 meters long. Extender is using 2.4 GHz frequency and channel 6.
Edit: The speed on extender reduces to half compared to main WiFi router.
Edit: The speed on extender reduces to half compared to main WiFi router.