Ill tell you what.....
A few yrs ago... I was literally halfway into Mexico.
In a rural area. Mountains. Handheld cell phones dont work- unless you reach the higher peaks.
When I got back home.... In my Inbox- was the Onstar monthly email.
With the emails datestamp, the OLM %, reported mileage, the vehicle 'phoned home'. I know exactly where I was on the day it sent the notice.
The vehicles 'stronger' antenna (output) was definitely able to contact distant cell towers.
So yeah- the vehicles cell antenna is higher output.... and yeah the phone was able to get on the Mexican cell towers and call home to send its info.
2010 FWD LT1-Gold Mist Metallic- seats 8.
Build Date- July 31, 2009-2nd day of Spring Hill 2010 production.
2013 Equinox 3.6L - 83,000
2010 Traverse 3.6L- 148,000
2003 Trailblazer 4.2L- 181,500