T-mobile Home Internet Wifi Hub loses internet frequently, not reliable.

So keep an eye upon it and watch the PCI for before and after a disconnect. Does it disconnect and reconnect to the same cell or another cell? The PCI, physical cell identifier, will tell you if it is making a transition to another tower or not. Keeping a record of the cellular metrics is also a clue. If the RSRP, signal receive power, RSRQ, signal receive quality, and SINR, signal to noise ratio, all change a fair amount from before and after again that would be good to know. It could be when the tower is more loaded there is the usual QoS but the signal could become weaker and then the source lock would more likely transition over to another source. I don't know what threshold needs to be met for a horizontal handoff but there are multiple factors that could come into play to cause the gateway to have a handoff to a stronger source. It is cellular delivery where mobile handhelds are going to be migrating from one tower to the next and they probably get priority over the home internet gateways when the cell delivery is busy. The traffic and loading is probably much more problematic in urban areas vs rural locations. There are more mobile handsets making handoffs from location to location so the routing has to keep up and the QoS controls have to be dealing with the ever changing environment. There is probably a great deal of work that needs to be done for the cellular home internet solution to be fully mature.  Connection loss is a very frustrating problem. No argument here on that topic. If you decide to hang onto the T-Mobile solution looking carefully at the cellular metrics and discussing what you have learned with engineers at waveform.com might be helpful. Sure, Waveform is in the business of selling antenna solutions but they know how the cellular is supposed to work and how their antenna solutions can help improve signal reception. If you are serious about staying with the T-Mobile solution, or have no other options where you are, then an external antenna might make a big difference. Here I have only T-Mobile or possibly Verizon and HughesNet. My neighbor has the Verizon solution as no more room on the T-Mobile tower, and he said it was working great for them.