Update - Wed 1-20-21
Speeds still holding with modem/router in it new most southern location, as advised by T Mobile Support last week.
Both signals going to the unit have been solid at 3 bars, one of them bounces up to 4 bars once in a while. I have learned 2 bars are not good.
Pretty much, I get 80 Mbps and higher all the time now and 30+ up which is way faster on the upload then my now canceled Spectrum internet!
If you are in a weaker area for cell signals from the tower, (like us) placement becomes critical, not so much to get service, you will always have ok service but to get the fastest speeds. Pervious postings up until last weekend have been up and down on the speeds, service always 100% reliable.
Now speeds are set, in stone it seems. Finger crossed, Im thrilled. Wife too, as she is into this stuff.
If you are in a weaker area, you need to find out where the cell towers are and move your modem around your home accordingly so you can literally "face" the direction to the cell tower. On T Mobiles advice we did so, they actually looked into it and told us where in our home to try, and wow, so far so good, wife and I had fun, we plugged the Modem;/router into a 100 Foot extension cord and literal moved the modem around the house watching the readings on the phone app and on my laptop for highest cell signal.
I have also read in TMobile forums that if you rotate the Nokia Modem and face the electric cord of the Router/Modem cord towards the location of the tower you will notice the signal readings on your computer or phone app go up! I tried it, amazing but true. It seems the internal modem antennas for the cell towers are slightly directional and you can actually optimize the cell signal by turning the Nokia Modem/Router a little bit at time while the back of the unit where the power cord is, is facing the tower. Once you have it positioned you can actually fine tune if watching the readings on your computer or phone app, just a little bit of a twist on the modem makes a difference on the signal strength, critical in a marginal area of cell coverage.
Which bring me to the next stage, I loved my set up in my central closet with my old Spectrum modem, Motorola router, power line adapters for wifes workstation, Ooma landline phone, back up power supply, ect.
However I could not get a reliable high speed cell tower signal in that closet, so had to move everything into a southern most area of my home, with is fine but that also places the built in router at the southern most area of my home, instead of central area.
I can say this, the built in router is very powerful, Im amazed at the signal I get throughout the house, literally no loss in speeds.
BUT one of my outdoor security cameras is at the most furthest possible part of the home from the router, outside the house, which is brick. Signal is not so good there, Im shocked I get any. All other cameras are fine. I have these cameras for fun more then security but ... I will some day think about a power line adapter for that one camera, OR wifi extender, OR maybe wire up my now unused Motorola router and put it back in the central part of the home, honestly, the TMobile router works so impressive, Im shocked, at the same time, if your a techie kind of person you will hate the basic GUI for changing settings, there is literally nothing you can change. This router/modem is for residential use, T-Mobile does not want it used commercially, its a violation of its terms of use and I am sure the limited GUI is for that reason.
One more thing, the phone app sucks and is very buggy. Keep in mind, we used our intensely for finding the proper location in our home and that worked great, but if you come to reply on it, on a daily basis, sooner or later the darn thing starts bugging out on you, no mater how much you removed and reinstall it. I do not think the typical person will have that issue, we for the reasons above of a weaker signal were constantly restarting/even defaulting the router ect and it gets confused. *L*
Part of the reason of defaulting the modem/router was we needed a sequence of powering up to get our Ooma landline working correctly with it. Otherwise we could only receive calls and not make calls. So we needed to powerup the Modem/router up from a powered down and defaulted state and then within seconds, power up the Ooma device. This sequence is not just with TMobile router, it happened with Spectrum too, its just the Tmobile router is a bit less refined and a few bugs left that makes it dicey until you get it right. Completely non issue of you don have Ooma.
Example of weak signal from center of home;
Following TMobile Support suggestion to try the southern most area of our home was correct, good signal and holding;