finding best location for T-Mobile home Internet gateway

As I recall when I remove the power to my Nokia router it will restart. Keep in mind if you remove the power and go to battery it will have to drop the WIFI radios & only operates the cellular radio. Once the router has a couple of minutes to complete the restart then the LED on top of the router should provide the bars and respond. 

My take is it is best to know where the tower is from the start. If you ask T-Mobile support where the tower(s) are in your location then you can focus on the windows which provide the best exposure to the signal. Once you get an initial idea of where it gets the best signal strength via the walkabout then I suggest to web into the 192.168.12.1 interface & see the actual signal strength for the primary & secondary cellular signals and also go the "Status" tab/page and find out the radio channels for both primary and secondary. If you post the signal parametric values to the conversation others can help you determine how it is functioning and how make suggestions that could help to improve the connections. Setting up a router via the cellular solution is a bit more demanding than just plugging in a cable modem so feel free to ask questions. The more you understand how it works the better you can get the solution to provide service you really want.