{http://www.wireless.org.au/~jhecker/helix/a2.jpg helical}



Helical [Antenna] are directional, but not as much as ParabolicAntenna.



They are almost always HomeBrew.



They are usually about 18dbi gain.



When using one, make sure the other end of your link also uses one, or you will lose 3dbi of gain. Also make sure theirs is wound the same direction as yours, or you will lose all signal.