I have one of these, but I disagree with John. I get better reception with the tiny included aerial than with the Status aerial on the caravan (useless junk). However I have found that for some reason the majority of caravan sites I have visited are in areas with no digital free view reception, so make sure you get one (which are more expensive) that pick up the old style analogue channels as well.
I give up on this and bought a 12V tv as while the laptop screen is fine for computing, only one person close up can watch it for tv due to the narrow viewing angles compared with a TV (eve LCD tvs).