Portable sat systems

I wonder if you could help me. Dealers are reluctant around here to install roof-based sat systems on our caravan for fear of water ingression. So we are looking at the portable versions. Is it a real problem or quite simple to find a satellite and is the whole process complicated. we will go for a 75 cm version to cover the Benelux countries and Germany where we tend to base ourselves.

Thanks in anticipation.

Moderator Edit: 

This post appears to be of a similar nature to your other recent post so it's been closed in order to prevent duplication.