GracieAllen

Eventually, T-Mobile got whatever was needed with the local towers done.  It STILL fluctuates wildly, but it USUALLY stays at a speed that makes things usable.  At good times it runs quite well.  It's better than the DSL we had. and cheaper.
 
Unfortunately, I guess that makes the best answer is to keep calling T-Mobile when it sucks, go through umpteen "support" people,  generally be a pain in the *ss, and have graphs like the above that show how inconsistent their service is.
 
With a little luck, after 4 - 5 months, hopefully they'll get things to the point where the service doesn't drop to zero, and will mostly work most of the time!  If you're lucky, it'll work well enough you rarely get buffering on the 480p tv, and downloads will be reasonably fast.

Eventually, T-Mobile got whatever was needed with the local towers done.  It STILL fluctuates wildly, but it USUALLY stays at a speed that makes things usable.  At good times it runs quite well.  It's better than the DSL we had. and cheaper.
 
Unfortunately, I guess that makes the best answer is to keep calling T-Mobile when it sucks, go through umpteen "support" people,  generally be a pain in the *ss, and have graphs like the above that show how inconsistent their service is.
 
With a little luck, after 4 - 5 months, hopefully they'll get things to the point where the service doesn't drop to zero, and will mostly work most of the time!  If you're lucky, it'll work well enough you rarely get buffering on the 480p tv, and downloads will be reasonably fast.

Thanks for the reply...
 
I'm not particularly bothered by the wild fluctuations, as long as the lowest speeds are high enough that everything keeps working.  Today, OUR load has been minimal - one computer doing little if anything with Internet data, and one TV at 720p - so basically 1 TV.
 
Attached (maybe) is the graph from 5 a.m. this morning to 10 pm this evening (not sure where it'll show up, but I uploaded it)...
 
All night it bounces around like crazy, and at 5 a.m. it jumps from 31 Mbps to 130, then back down to 80.  And starts a gradual decline until around 11:00 the lows are below 10 Mbps.  And gets worse.  Then shortly after noon it goes back up and stays at around 30 Mbps for a while, and around 2 pm, it falls on it's face with a whole BUNCH of values well below 1 Mbps and barely getting into the teens Mbps all the way through 10 pm...  So, at LEAST 8 HOURS of miserable performance on a Sunday night.  And it looked very much the same most evenings last week.  Generally it didn't deteriorate QUITE this early, but once it hit "kids coming home from school" time, it pretty much tanks every day.
 
We've got three towers the Home Internet uses (according to T-Mobile support).  One "has problems" and T-Mobile excluded our gateway from that one (I have no idea HOW they did this, but I was TOLD they did).  The tower it's USING (again, according to T-Mobile) is straight South about 2 blocks and I can see it from where the box is.  The third one is East and less than 1/4 mile, and again, I can look out the window at it.
 
Both cell phones act the same way when in 5G.  If I turn OFF 5G on the cell phones I get about 180 Mbps at WORST, and generally around 260.  This is all using speedtest.net.  Unfortunately, the HI box doesn't have the ability to exclude 5G and use LTE.  I presume it was the cheapest, simplest device they could come up with to provide at no additional charge.  Very little configurability and apparently not smart enough to pick the band/service/whatever that appears to have the most available capacity...
 
I can live with the wide fluctuations as long as they stay HIGH enough at the worst so the service doesn't get down to the point where it's unusable...  I'll try talking to T-Mobile Support again tomorrow, but if this service is going to be this crummy for an extended period, the Home Internet box is going back as we're within the 15-day window through this week.