My home internet gateway locks to B12 despite a good 5G signal which works sometimes.

  • 10 June 2021
  • 7 replies


Looks like I wont be able to stay with TMobile even though it works so well most of the time. It seems like the gateway will just get stuck on B12 with no secondary even though N41 and B2 are strong and nearby.


Locking to B12 causes my speeds to go from 600MBPS to 17MBPS. I am positive its not a congestion issue as it will happen in the middle of the night. 


Restarting the gateway when its connected to B2 and N71 will reproduce the problem. This is not a tower issue. This is clearly the gateway getting stuck and is reproducible.


What a bummer.


7 replies

I have the exact same issue with the same bands. I have had my service for 2 days with drop of secondary  N41) and shift to B12. It has happened to me in the evening on both days. I don’t believe it is a gateway issue however. The first time it happened I did a soft reset, power off, factory reset, and pulled the sim card. Came back to B12 every time. In my opinion T-mobile is load balancing the towers because of lack of 5G capacity. I challenged customer service and they pretty much said this was the case and they are working on tower upgrades. By the way I am ½ mile from the tower and have full bar service. I have 1G fiber service so I don’t need to keep this. I wanted to try it because I was so close to the tower. Shame because it works well when connected to 5G...

I have the exact same problem and I’m about 100 yards from their cell tower. When I first got the gateway tower I could get the secondary signal n41 and got fantastic speeds of over 500Mbps downloads. After it was lost I moved the tower to different windows facing the tower and got it a few more times but now I have not gotten the 5G secondary signal for over 10 days. Very frustrating. Personally, since I can get over 700Mbps on my T-Mobile iPhone 12 consistently, I believe they have a firmware design flaw in the gateway tower since the B12 band is so strong it overlooks the nearly as strong n41 5G band. They need to change their algorithm to accept the n41 band even if it is a little weaker in signal strength. 

Had the same problem here and I live a block away from the tower.  Once I was able to get my 5G secondary signal back, I rotated the front of the can counter-clockwise about 120 degrees from the antenna to get the primary signal down while increasing the secondary signal.  Hopefully it doesn’t lock back to only B12 without the secondary signal again.  My secondary signal RSRP is usually around -60 dBm but today is cloudy with light rain but luckily hasn’t switched back to B12.  I also have the can sitting on a usb fan to keep it cool.  I’m on s/w version 178 and hopefully they will fix this problem on the next update.


Speed Test

Strange how today is still cloudy but now getting RSRP -62 dBm instead about -80 dBm on my secondary signal.   Guess it’s not the weather affecting the RSRP.  Still have the northwest end of the can pointing towards antenna tower.  Did not rotate it and have B2/n71.



Bands B12 (4g lte)  - B2/N41 - tower 0.5 mi away

These are my stats when I have good results. I try to move/rotate the can to keep the Primary SNR down to an indication of 4 bars and between 0-5 db. The secondary is then much stronger with 4 bars but SNR of between 25-35 db. That said the longest duration of maintaining lock on B2/41 is about 3 days. Average about 400 down and 45 up and do a lot of 1080/4k streaming with no issues. I  also have a fan underneath the can and all wifi off except one 2.4 band. I run an ASUS AX-58U wifi 6 router with one AiMesh node to handle the wifi duties. I have 12 various wifi devices connected and use the two hard wired LAN ports out of T-Mobile can out to my ASUS Router and Sony TV. 


The best I have been able to figure to this point is it is either a firmware issue or 5G network load balancing that is causing the 5G secondary signal drops. Even though I have taken the So called (over heating issue) with the fan and turning off most of the wifi I am far from convinced that is the main issue.

I have had the service for a month and I can say that other than dropping the 5G band and locking to B12 until I force it back I am quite happy with the results for the cost. I came from AT&T 1G service which was lighting fast and very dependable. As I was so close to a good tower I wanted to give T-Mobile a go and try to support their far I am ok with it.

Hopefully the next update allows us to choose which bands to lock on instead automatically.  It’s great not having to deal with a cable line so no cable guy to come for repairs.

i just found this thread. same issue.

also the wifi was glitch out to. ie turn off. yet still showing.