Helix antennas are directional antennas for circular polarisation mainly developed for satellite communications but just as well usable for terrestrial operations.Due to physics based reasons the circular polarisation shows significant advantages when the received signal may consist of a mix of all kinds of polarisations due to heavy reflections. As an example: If the phase of a received signal is perpendicular to the antenna plane the resulting signal level can be up to 18 dB (3 S-levels) down compared to a normal yagi! The right-hand circular polarisation originates from a helix - the antenna radiates into the direction of the helix. The reflector directs the electromagnetic energy forward; to decrease the antenna's wind load the reflector is perforated (many small holes). All antennas except the type Helix 70-2 are designed for fore-mast installation. By means of power splitters the helix antennas can be combined to form antenna groups of 2 or 4. The antennas have a standard N-connector and are made of non-corrosive aluminum material with all nuts and bolts made of stainless steel. The mast clamp is hot dipped galvanized.Frequency range 1250-1300 Gain (right hand circular) 13Turns 20SWR 1.5Max. power load 500wConnector N F/MLength 1.3mScreen diameter 22cmWeight 1.4kg