How can I force a Samsung Galaxy S8+ on Verizon to use 3g, not 4g?

[Android Central Question]

I'm trying out a cell phone booster for camping trips to remote areas. It does a great job of improving 3g signal, but by phone keeps wanting to switch to much weaker 4g.

Verizon had me do this:
1. Settings / Connections / Mobile Networks / Network Mode: Change from "Global" to "LTE/CDMA."
2. Settings / Connections / Advanced Calling: Switch off

It didn't work. It still tries to switch to 4g. Then Verizon said it doesn't really work but was worth a try. They've got nothing else. Anyone?

 

[Rukbat]

No, the phone will use 4G as long as there's any 4G signal available, even if you have solid 3G and useless 4G. It's one of the big problems with the entire communications protocol in the cellphone industry. When you get to a place with no 4G at all, but weak 3G, the booster may help. (Although such spots are so rare that they probably have a list of all of them on a Post-It note.) Most of the time, since 4G was built over 3G areas, you'll lose 3G long before you lose 4G. The solution for remote camping trips is a carrier that covers area, not population, so wherever you go, there's coverage. (For really remote areas, there's always satellite phone, if you have machines counting your money.)