title_body: What is the difference between a patch and helical antenna? I have seen both patch and helical antenna when shopping for video receiver antennae. All I know is that they are both directional antennae. Do these types of antennae have any inherent performance differences? (I´m talking specifically about 6-turn helical antennae compared to patch antennae)
upvoted_answer: It is my understanding that in general a helical antenna will perform better than a patch antenna.  I should really find a source for that though.  However a patch antenna is flat or nearly flat and thus easier to pack and transport.  The bulkiness of the helical is probably the main drawback.
  
  RcModelReviews has some great instructions on building your own helical antenna.  Another nice thing about the helical is that the number of turns determines how directional they are, so it is easy to see exactly what you have, know that they are polarized and all that.  With a patch, it is not so easy to tell exactly what they are.