Hi Kathi,
The challenge is that you probably need 2 devices that work together, or a combination unit. You can get a WiFi Signal Booster with high performance antenna,
like this. That'll give you a significant improvement. BUT, it has to plug into something compatible. I used to use the Rosewill Booster plugged into a
Pepwave Surf on the Go Router (in place of the stock antenna on the Pepwave).
The Pepwave had 3 weak points. 1) It was difficult to configure - very hard for a someone without a lot of experience. 2) It only handles 2.4 GHz signals. While that's the majority of campgrounds today, the move to 5.0 GHz is underway, providing many improvements. 3) The internal transfer of data is a bit slow for anything other than casual web browsing. It'll work for streaming video, for example, but just barely.
The Pepwave has other redeeming features, like support for connecting to a cell data network (AT&T, Verizon, etc), if you have a Jetpack that is compatible.
Last year I switched to an
Edimax WISP Router that is very reasonably priced. I think it's easier to set up and configure than the Pepwave, but it's still not what I would call easy. It has very good reception, supports both 2.4 GHz and 5.0 GHz, and is very fast. I use it in WISP mode. In WISP mode, all of your devices connect via the router. You make one connection to the campground WiFi. And if at a campground that has Tengo Internet, the coupon code gets the router authenticated on Tengo, so you only need 1 coupon code.
None of this stuff is very easy. And if the campground WiFi isn't very good, or the campground is crowded, you may find that nothing helps very much. But if you're willing to experiment, you should be able to get better service than what you currently have.