So I know Western Digital sells a range extender (Western Digital My Net Range Extender). I want to know if it actually just extends the range of my current routers WiFi coverage or does it use my routers WiFi to create another network? don't tell me I can just set up the SSID to switch automatically to the one with strongest connection because I know that and don't want that.
Also, do these routers (WD my net N600) or (WD my net N750) support wireless repeating? And if they do, will they create anothenetwork or just extend my WiFi coverage?
There is no such thing as a range extender in the form you describe. ALL create another wireless network no matter what they say. Now it may use the same IP subnets but the wireless signals do overlap and interfere with each other. They all have the problem of duplicate SSID and no control over which device your wireless actually connects to. Even when they work perfectly wireless repeaters lose 1/2 the bandwidth and many times much more.
They do make other devices that everyone used to call repeaters before all the cheap crap got on the market. These repeaters use 2 different radios, one to talk to the router and the second to talk to the clients. Since these act as 2 units you have much more control over the channels and can even use different SSID if you like. They tend to be expensive so you are better off building your own with 2 units. A device to act as a cleint bridge back to the router cabled to a second device acting as a AP to talk to the end clients.