Robert,
Try the following:
Remove the TV from the van, take it indoors and plug it in next to your house TV. Assuming you have a roof top TV aerial, switch the TV aerial lead over and tune in the channels. Compare the image with your home TV picture.
If the TV doesn't provide images of similar picture quality - the TV is probably faulty.
If the picture quality is a similar quality, return the TV to the van.
Assuming your van is parked at home, now run the TV in the van and compare the image quality. It will be worse because the Status omni-directional trades signal strength against not having to set up a directional aerial.
If the signal quality is now so poor that you can't live with the image, change the Status omni-aerial for a Status directional aerial.
A directional aerial is best because: they receive a stronger signal, they reject interfering signals
An omni-direction aerial can be OK in a strong signal area, but only if competing signals are absent.
A booster (amplifier) system is not such a great solution because they amplify the signal and the noise by the same amount - so no net gain. If the noise is very low, then they can help.
Freeview boxes need a strong signal to work.
Robert