Cell signal at home was excellent, now terrible

It sounds like you have a "real" booster that takes the real cell tower signal and amplifies it and rebroadcasts it. Those I've found are really flaky because of all the regulations on how much the unit can re-broadcast. I used one for a while and found I basically had to be within a few feet of the indoor antenna. I don't believe AT&T sells one of those they may re-sell someone else's.

This sub-forum is about the AT&T Cell booster which isn't really a booster it's a fem2cell, which basically broadcasts a real cell signal locally and needs connected to the internet on the backend and sends all your calls and txt's back through the internet. YOu need only a few mbps up and down for it to function. Fibre is great, but not required.

If you have newer devices wifi calling is the preferred solution, simply turn it on in your phones settings and no additional devices or hardware or connections needed.  When your cell tower signal is low and you have reliable wifi your phone will automatically switch to wifi-c and your calls and txt's will be routed through your wifi signal.

If your not amenable to wifi-calling then the at&t booster is the next best solution. Your cellbooster I would consider as a last resort.

Read my Cellular Booster Tech Guide, the link is in my sig line. It is a little dated now but the basic information is still solid. It could be that whatever cellular booster you purchased from Amazon doesn't cover all of the AT&T bands/frequencies in your area. A professional installer will have the equipment to determine what frequencies/bands are available in your area for AT&T, recommend the cellular booster, and install/adjust it. Some cellular boosters are designed for use with multiple providers.

AT&T doesn't sell a cellular booster. What they do offer is the Cell Booster, which is a misnomer because it is actually a femtocell and not a actual cellular booster. What it does is use your internet connection to reach the AT&T Mobility Servers by broadcasting an LTE signal in your house that your phone connects to.

WiFi-C (WiFi Callling) is the preferred method for improving poor in-home coverage if your phone is capable and you have a good WiFi connection. It's similar to the femtocell in that is uses your internet connection to reach AT&T but it does this thru your WiFi connection and does not broadcast a signal for your phone to detect.

About the booster not being the correct frequency, why did it work for a week or so?  I doubt at&t just decided to change the frequencies they work on in the last few weeks?  It doesn't make sense because it did work.  Super frustrating.

@dorlow  You are correct. AT&T can't just change frequencies or bands without FCC approval so it wasn't on the AT&T side. Without knowing which cellular booster you purchase it's hard to say why it worked briefly and now it doesn't. There is a possibility that AT&T is doing tower maintenance and has to use a temporary band but even that I'm not sure is a reason.

Read my Cellular Booster Technical Guide. There may be something in there that helps you. WeBoost is one of the more popular and reliable brands of cellular boosters but there are a couple of others listed in the Guide.

The guide appears to reference a cell booster that just basically uses internet to get the phone service to the house and then it works as a cell tower in my house using the internet.  The cell booster I bought has nothing to do with the internet.  It's picking up the cellular connection on the outside antenna and then boosting it and then repeating it inside the house.  Anything that requires a good broadband connection in the house won't work because I don't have broadband available to my house.

Below is the booster I bought.

https://www.amazon.com/gp/product/B08GXDCK9S/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

My home internet is at&t cellular hotspot that I have an antenna about 30 feet in the air to get a decent signal.  It's on the same pole as the repeater.  The 4G antenna works great.  Repeater... not so much.

found out today that fiber won't be installed probably before November... so I have to make this work until then.

So, I just looked again at the band selector and it looks like the band number doesn't match the antenna's band.  So, I just ordered another booster that does.  Weird that it did work though for a while.

@dorlow  I have two Guides linked in my sig line. One is for AT&T's Cell Booster, which is not a cellular booster but a femtocell that uses your internet connection to reach AT&T. AT&T unfortunately named their Nokia femtocell the Cell Booster, which is misleading.

The other Guide, is my Cellular Booster Guide and it goes into detail on how cellular boosters work, the various types, how signal strength/bands/frequencies are determined and which bands AT&T uses. My Cell Booster Guide actually has more current information, post 3G shutdown, on which bands and frequencies that AT&T is currently using. They do change from service area to service area so that's why you need to determine what is being broadcast to your location and purchase the appropriate cellular booster. You also need a phone that meets AT&T's post-3G shutdown requirements to see if it's still compatible with AT&T.

The cellular booster you linked to is ok, but it is not up to the caliber of the ones that are listed in my Cellular Booster Guide (not to be confused with my AT&T Cell Booster Technical Guide).

I have had similar problems... several times over the last 10 years or so.  Unfortunately I haven't the resources for working up a proof of what I think the problem s like these are do to. 

To be brief, it seems likely that the companies (your choice of hardware manufacturers or service providers), engineer the phones to have great performance, but for a short time. That way you'll go buy another phone about a year after the last one... 😱