I've yet to have a camper that had adequate coax fittings. I worked for cable TV once upon a time and know how to put together a proper fitting. When the "Stinger" isn't long enough, or if the braiding is not done right, or if the fitting isn't installed upon the plastic center shielding right, or, or, or - you get bad signal. I've redone them on both of my campers, my house, and my mom's house as well.
There's a very good guide for the DIY fittings you can buy here (although I don't think the first photo of a crimped fitting makes the grade):
I have all of the proper tools to use the crimped fittings, so I prefer to use them. They last much longer.
I would also recommend purchasing a coax cutter like the one below. They make the job VERY easy.
Also, one of the biggest problems with service calls was the fact that splitters can go bad over time. If you're having problems with your cable that worked well to begin with, that should be your first thing to look at.
Hope this helps...