I have a Seiki as one of our 5 tvs in our coach, and it's never been a problem picking up normal cable tv thru the campground, whether digital or not. But, I also realize that some of the different 'lines' of Seiki tvs, as well as others, may not all be built the same.
You may actually NOT have a problem with the TV, but one of the connection between the cable outlet at the campground, and your TV - otherwise, all the cables, connections in between, and how you have 'programmed' your TV to 'find' these channels, or the signal.
It can get a little confusing when you have to remember to turn 'off' the antenna booster, change your TV's 'input' to 'cable', and also RESCAN your channels... and that's IF the cable outlet for the park is actually providing the signal, and you have connected the external coax cable to the 'correct' input for your RV. Crazy!
as for Satellite, you can easily start with a simple KingTailgater or DishPlaymaker or similar 'portable' antenna, along with one of the receiver types of your choice - they many times sell them in a 'package' deal, as you might even find on the DISH website when you sign up for SERVICE - choosing the 'package' of CHannels that suits you.
The antenna - $300-$400
The receiver - $100, or higher, or a monthly rental of $10 or so
The Programming - $50 to $150 monthly, or with Dish, a 'pay as you go' monthly where you can cut off billing when you are not 'camping'.
(with these types of 'portable' antennas, the power to the antenna comes from the coax cable connecting it with the receiver - so no need for any type of 'power' for wherever you choose to place the antenna for where you are camping... and running a coax directly from the antenna to the receiver is the best way to start, at least until you've familiarized yourself with how it all works - don't try to use any 'satellite' connection on your receive since they can be problematic, and even if they work may only provide a thru-put signal to the living room tv, not the bedroom or any others.)
'14 Palazzo 33.3 bunkhouse 34' diesel
KingTailgater2 Dish HD, 100w/5a SOLAR, BlueOx
100,000+mi since '14 - US, Alaska, Canada.... formerly Georgia, then NorthCarolina, now Alabama : )