I was wondering how the Avtex STH3000 compares with the Vision Plus Image 620 4G Digital Directional TV Aerial, any one have any previous experience on a comparison. i gather if you have the Avtex tv it powers there own brand aerial but how they compare i haven't a clue apart from the Avtex would just stick on your window but you would imagine rightly or wrongly that the Vision plus one on top of a pole clamped to your jockey wheel would be better but vastly bulkier for a tiny caravan?