Trying to do the same thing. Find out if the FP3 would work on US cell carriers. It’s a learning process and even if it does not work here in the US or I decide not to try the FP3 I have learned alot.
I found this website that describes each band that each of the carriers use.
If I understand correctly:
AT&T - would not work well as they use band 17 as the primary “backbone” of the network.
T-Mobile - Would work on bands 2 and 4.
Did not look at the other carriers yet. Any comments as to the accuracy or inaccuracy of the data?
Thanks,
Rich