Not fast - Not reliable

If you have the mobile application on your phone get the cellular metrics from the gateway and post them to the conversation. Maybe there is a way to get a better signal but knowing the RSRP, RSRQ, and SINR values for the 4G and 5G NR signals can be helpful. The positioning with the LED and the bars does not tell you enough about both the 4G LTE and 5G NR signals. If you can improve the 5G NR signal strength and quality it might just hold. 

http://192.168.12.1/TMI/v1/gateway?get=all <-To also get cellular metrics from the GW.

You would also benefit from knowing where the tower is and how far from you it is. Getting the gateway so it can receive the signal better may be possible without and external antenna. If you do have a good path to the tower without too many trees, hills, buildings, etc… degrading the signal then an external antenna can be helpful. Use the cellmapper.net website to find the PCI, physical cell identifier for the 4G and 5G signals. The cellular metrics should provide the PCI value and with that you should be able to locate the tower. If you have an n71 signal a 2X2 MIMO antenna is sufficient and a vendor like Waveform.com can help you understand what could possibly work for you and provide information about setup. 

If the T-Mobile solution just does not reach where you are maybe Verizon or AT&T have service that could reach you but then contract and fees are a downside to that picture. If you post more information about the operation of your gateway and the cellular metrics users on the community can offer more suggestions. You might just get it stable and get what you want.

Well, metrics do help explain the behavior some. There appears to be some noise that influences the signal quality. The signal strength RSRP -96 on the 5G is in the "Medium" range and the RSRQ -14 is in the "Good" range but the SINR at -3 dB is very "Weak". Both signals need to be improved, if possible, but the noise might be an issue. It might just be other signals in the area or some other influence in the area that accounts for the noise. 

The 4G LTE signal is weak so uploads probably stink. Both signals suffer from noise so performance is probably an issue. You can try different locations in your home to see if the signal metrics improve. With cellular it takes a little more effort to get it working in some situations. Your location might be on the fringe of the cellular range. Locating the tower(s) for gateway placement and experimenting a bit is really what it takes. If the 5G signal is on the n71 band that 600 MHz can travel out roughly 10 miles but being on the outer limits or having a signal that is degraded by trees, hills, buildings, etc… will impact functionality. With the PCI, physical cell identifier, you can find the cell where the signals are sourced from. Cellmapper.net is NOT 100% as they data there comes from users that post up to the server so if no one has contributed information on a given 5G tower it may not be seen. You can filter by 4G and 5G with the panel on the left and that helps reduce clutter in the results especially when there are lots of towers in the area. Of course you have to select the carrier first and provide location info to begin. Using cellmapper.net and Google Earth measuring for the distance and looking at the terrain between you and the tower helps see what is possibly going on. 

If the distance to the tower is say 3-5 miles and the 5G signal is n71 with an external antenna the noise could probably be reduced some but the antenna used and placement would take a bit of work. Yes it is not inexpensive to add an external antenna. I considered it but my cellular metrics are actually really good even roughly 4-5 miles from the tower but I have actual line of sight given the elevation of the tower and that our home is up on a ridge. Every situation is different and some are more challenging than others. 

You can run speed testing with speedtest.net and fast.com to better profile the performance. If ping latency is higher and jitter is higher it would not surprise me given the cellular metrics. Locating the signal source(s), experimenting with the location of the gateway, improving the cellular metrics, verifying the operation with the speed testing "tools" are really what it takes to possibly get a better signal. If T-Mobile is still working on the equipment in the area that adds frustration to the efforts. We had two episodes here in 2021 where work was being done on the tower/equipment and for days the signal was flakey. Once they upgraded equipment and got the programming dialed in the signals improved and became stable. I joined during the BETA phase in January 2021 so I knew there would be possible disruptions. I had no other reasonable solution here. I don't consider Hughes Net a reasonable solution. The only cable solution here is very limited for delivery and much more expensive if it can be had but everyone on the street that has it knows it is slow and unreliable. For a cable solution that is pretty lame service. I believe the cable here is over subscribed and old gear. 

The T-Mobile home internet solution may not be the best for your location but without some experimentation you will not know what is possible. T-Mobile or any cellular vendor cannot control the external factors for every single location. If you start to research cellular as much as I have you will quickly begin to see there is a percentage of users that are difficult or impossible  to provide service to. Sorry for the long response but hopefully it helps you pick it apart. 

Currently 3 bars, RSRP= -107, RSRQ = -13, SINR = 2 on the LTE side.  5G side = RSRQ -14, RSRP -96, SINR -3.  Gate on south side of house.  I used the location map and it points to south side.  Window in front of it, window to the west of it.  2nd story.   I'll check cellmapper and see if it aligns with TMobile location function in app.   Thanks.  Already have a primary network that runs my office and house.  Lots of connections.  TMobile was too good a deal so figured I'd try.  But reliability is paramount and from what I am reading I'm not alone in being let down.  Gonna be interesting to see what cellmapper says.   Gracias

Thank you for this extremely helpful info.  I did look at cell mapper and compared to what TMobile location finder was telling me.  They align.  TMobile says "extended range" and I do have trees that may be an issue.  Closest tower shows 3 mile range.  I am in a bedroom community (suburbs with predominant housing).  Most people in the area have networks with home automation.  Networks are mainly Xfinity and Dish.  Many people work from home.  I doubt any adult/teen in the area is without at least a cell phone.  Figure I have 15 days to find the best place for gateway.  So far I am on 4th spot without improvement.  Currently sitting at 3 bars.  Stats are roughly the same as last night.

Again, thanks for the detail.  It is very much appreciated

Would you be able to help me as well? I'm sort of in the same boat. Have had T-Mobile internet for about 9 months and usually only have 2 bars but only recently have had lots of trouble. Signal in and out frequently this week. Not sure why now. 
5G numbers. RSRP -105, RSRQ -12, SINR 8. LTE -99, -13, 13. I appreciate any insight!

Re: 5G numbers. RSRP -105, RSRQ -12, SINR 8. LTE -99, -13, 13.

Sure would be happy to try to help you out. With the table for the cellular metrics values I can see right off the 5G signal the GW is reporting is very weak. The RSRP is the signal receive power, the RSRQ is a reflection of the quality of the signal, and the SINR reflects noise level for the signal. The 4G LTE is in the medium range for strength and the RSRQ and SINR are in the good range so though the 4G signal is not good or excellent range at least the quality of that signal is not terrible. With the 5G values I can understand how you would have, "lots of trouble”. It could be the distance to the tower and/or a combination of external factors that degrade the signal. 

If you can find out where the tower is that delivers the 5G signal it could really help to improve the positioning of the gateway to try to get a better reception of the signals. There are so many different factors that can reduce the signal. If you have metal screens, a stucco house, i.e. with the wire reinforcement for the stucco, large trees or structures between your home and the signal source, and well a number of other things that lead to signal disruption. Every location has a unique set of factors. 

Do you have the Nokia GW or the Arcadyan GW? The Nokia is the cylinder shaped router and the Arcadyan is more of a square design with rounded corners and an LED screen on the front vs the small LED screen on the top. The LED reporting is a very generic display so knowing and understanding the cellular metrics helps to improve the signal. The software interface for the Nokia via a web browser is more informative than the Arcadyan GW so how much information is available and the ease of access depends upon the model of the gateway you have.

If your GW is the Nokia then using the web interface via the 192.168.12.1 gateway address is a friendly way to get more info. With the web interface you can obtain the PCI, physical cell identifiers, for the 4G and 5G cells and use cellmapper.net to find the tower. With a combination of the database info from cellmapper.net and google earth maps looking at the terrain between the home and tower can help some to understand what external factors may be involved. If you have trees and hills and the tower location is beyond them that is a condition to consider. The distance to the tower also is very helpful to know as it helps set expectations for the signal delivery. If you are on the edge of the cell delivery then the values your gateway report could be explained, in part, due to distance to the tower. If you need pointers as to how to use cellmapper.net just ask questions. Cell Mapper is roughly 80% complete information. It relies upon user content delivered to the server to get confirmed tower information into the database. Many people have contributed data to the servers but it is not 100%. Many 4G LTE towers will easily be found via the PCI cell values but in some cases with more recent 5G deployments the data to show where that tower is that delivers that cell signal may not yet be recorded. Using cellmapper.net via the browser is not hard. Using the filters for 4G LTE or 5G NR towers/signals rather than no filter really helps get a cleaner reporting on the map to reduce clutter and find what you want. 

If you cant get the information from say cellmapper.net then T-Mobile support engineers "should" be able to provide more information about tower location. Getting your gateway situated with the best exposure to the source signals is very important. It can be a bit confusing at times as the signal can be direct or reflected. In some cases placement in a room in front of the window may not yield the best reception. You want to avoid putting the GW direct in a window where it would get too much heat from the sun through the glass. Taking the GW on a walk about reviewing the LED values as a starting point and then also reviewing the metrics to see detail should help. If you cant improve over 2 bars on the LED then it might be possible to use an external antenna solution but depending upon your ability to understand the process or lack of assistance from someone who does can make that a challenge. There is good information about external antennas but first see if you can just improve the reception by testing different locations for the gateway placement. Maybe things have changed since you placed the gateway when you got it and another location in the home is better.  I can't say much more without having a better understanding of the situation.