Bob,
We want to outfit a van with a 4' dish for Balloon Tracking live downlink video and not have it blow off the roof at 70 MPH.
I'm considering changing over many of our student projects to high altitude "cubesats" that can be completed in one semester and actually LAUNCHED (by
Please be careful - even a wire dish generates an enormous drag at 70MPH.
Do you intend to actually use the antenna while driving, or only while parked? In either case, you would need a stabilized antenna with a radome (see the Swe-Dish SOTM), or a folding roof antenna like the Swe-Dish DA150 series (see http://www.rockwellcollins.com/sitecore/content/Data/Products/Communications... ). I don't work for Rockwell Collins / Swe-Dish or have any relationship with them.
Commercial folding antennas are just expensive, while commercial stabilized antennas are terribly expensive. But they may be worth the cost if you are saving sat launches - and besides, I am sure anyone on this list would find good uses for them :)
Miguel, EA1ICZ