We see people posting in rural internet and RV living forums and groups daily about slow and inconsistent speeds through their cellular-connected devices. Sometimes the complaints are around video streaming quality and others around simple webpage loading times. My first question to these users is always, "what's your signal strength?" Nine times out of ten, I have to walk people through finding the diagnostic pages in their modem/router, and typically, we find that signal strength is the culprit to their poor experiences!
Many devices like the Nighthawk, Cradlepoint, etc. allow for external antennas to be connected. I can't think of a situation where the use of an external antenna would ever be worse than using the weaker internal antennas. There are several different types of external antennas and connectors. An omnidirectional antenna will allow you to connect the antenna to your device and get a better signal without aiming the antenna. This usually helps improve signal and is suitable for an RV or other moving vehicle. If you want to improve your signal strength, you want to focus on directional Yagi antennas.
Directional antennas are reasonably simple to install but require some research to get them aimed correctly. Using a website or app like Cell Mapper, you can choose your carrier and location to find the closest cell sites. This will let you point the antennas in the right direction. There are also a bunch of websites that explain how to aim the antennas for optimal usage accurately. It's suggested that if your device supports it, you should use 2 Yagi antennas, as shown in the images below. Setting them at a 45-degree angle is essential. I typically refer people to this link when learning to aim antennas:
https://support.itel.com/hc/en-us/articles/115004728406-Location-and-Aiming-of-External-LTE-Antennas
As for my personal gear selection, I use a Cradlepoint CBA850 with 2 Wilson Yagi antennas. Take note! I also use lighting arrestors on my ethernet AND antenna cables. This will prevent damage to equipment inside my house in the event of a lightning strike! Your equipment might have different connectors for the antennas from my Cradlepoint, so be sure to do a bit of research when selecting the antenna cables for your specific device.
All that said, here's what I'm using!
1. Antennas (2 of these) - https://amzn.to/2DgiUzQ
2. Cables (you'll need two, and you want to keep these AS SHORT AS POSSIBLE to limit signal loss. Also, your connectors on the modem/router side might be different, so double check these are the right cables for your setup!) - https://amzn.to/3jO3qnI
3. Lightning Arrestors for antenna cables (you'll need 2 AND AGAIN, be sure these are the right connector for your setup!) - https://amzn.to/3f8WZIb
4. Lightning arrestors for CAT5/6 cables (you'll need one to protect any routers/switches/ethernet gear you have connected to your cellular modem/router/device.) - https://amzn.to/39BwHgA
5. Here's a link to the modem I am using from Cradlepoint. You can find these used (like I did) for much cheaper than new ones. - https://ebay.to/3f7QANz