In article 2017021619553985684-savageduck1@REMOVESPAMmecom,
Savageduck wrote:

I can only tell you that while Verizon has good coverage with at least
two towers where I live, T-Mobile is mediocre and shows no towers, and
both AT&T and Sprint are poor to non-existant, also showing no local
towers. This leads me to believe that T-Mobile, At&T, and Sprint are
actually roaming in my location, using the Verizon towers.

sprint probably is, but att/tmo aren't.