I have the old Speedboost by Wilson. For portability, we mounted it to a little plank and carry it and the magnetic antenna in a little leather bag.
Sometimes when traveling we put the bag in the truck to make calls while driving. At night, we move it all to the camper.
Once we checked into a State Park in Arkansas and were told there was no phone service because we were in a valley on the lake. We'd have to drive out of the park 1/4 mile to the top of a hill to use our phones.
We moved the antenna all over, including all over the roof of the camper to no avail. Then, by chance, I discovered a spot on the truck hood that gave us 1 or 2 bars. We set a folding chair next to the truck to make calls and we called it 'the phone booth'. They DO work if there's any chance of having some signal to boost. 
