Cell signal boosters can work under the right circumstances. The specific device you linked at Amazon, as I understand it, requires a T-Mobile account (not merely a T-Mobile network SIM) and is 4G LTE only (no 5G), which would explain the relatively inexpensive price.
Is there something you are trying to solve? Though it works differently from RW’s now defunct WiFi-first technology (with the right phone) would provide WiFi calling and, in some cases, text messaging over WiFi.
I posted this originally in that Google Pixel 6A wifi calling thread: https://forums.rwusers.com/discussion/41/new-pixel-6a-phone-no-wi-fi-calls/
I thought it might help get them a little better T-mobile coverage inside their home.
In my house, one bedroom upstairs gets a much better signal than the rest of the house.
I thought about placing one of these up there and using it to direct some of that coverage to the rest of the house. The price is almost low enough to try it, then dispose of it, if it does no good.
We still have a Pixel 4a/5g on the old My choice plan that cannot do MMS over Wifi.
If you read through some comments on this booster, they say it does not require you to plug it into ethernet.
Please accept my apologies for missing the connection.
In any event T-Mobile’s CellSpot is a microcell device. Microcells create a tiny cellular tower inside a building. @jben correctly points outs, they rely on one’s WiFi network to do so. Microcells are not cellular signal repeaters nor do they amplify weak cellular signals already existing in a given area. Theoretically, there wouldn’t need to be any cellular signal in a given area to deploy a microcell.
As I understand it, T-Mobile’s CellSpot devices must be activated on a T-Mobile account. To the best of my knowledge, they cannot be activated as standalone devices without T-Mobile service for use with MVNOs such as RW.
A stable albeit weak cell signal must reach your home. There are apps that can tell you the signal strength inside and outside of your home.
The unit you purchase must work with the available signal. Signal strength apps can help identify the frequency band your signal is in.
Best locations for the receiving antenna are, in best to worse order, roof, attic, indoor where decent signal is found.
Transmitting antenna (often in the unit itself) needs to be located where a reasonably good signal is available throughout your home.
My son-in-law has a machine shop inside a steel building in an area with a weak Verizon signal. He mounted the receiving antenna on the roof and the transmitting antenna on the 2 1/2 story high ceiling. He gets a solid, reliable signal everywhere in his shop and finds himself coming into the shop to make calls because the signal is so much better inside than outside.