I live full time in an RV so I'm always connecting to 'free' hotspots in campgrounds. It's very common for parks to have a free connection (hotspot) running inside a pay for service wireless network. In these situations the hotspsot is typically a router with a crummy antenna (if any). I use a pepwave surf mini connected to a linksys router for connecting to my access point. I put this antenna on the pepwave and mounted it on a pole outside my motorhome, about 3' above the roof. It boosted my signal about 9 db and took me from no bars on the pepwave to a solid signal that never goes away.
I highly recommend this setup. Pepwave by itself is awesome in most situations, connecting when others can't even see the access point. With the addition of this antenna I don't think I'll ever be without hotspot access.