SVP Aerospace´s quad-helix omni (AC-204 / AC-504) design brings the advantages of the characteristic quad-helix antenna radiation pattern to mobile ENG uplink/downlink applications.

The AC-204 / AC-504 antennas provide a circularly polarized omnidirectional radiation pattern with peak gain of 4dBi at 30 degrees above the horizon, and then decreasing gain, with no nulls, as the elevation angle increases to the overhead 90 degree direction. The scape of this radiation pattern naturally compensates for the change in path loss as a mobile transmitter moves from the overhead direction out towards the horizon.

The circular polarization improves signal robustness in multipath environments and in motion links. It can be installed in the fuselage of the helicopter or in an actuator arm where it is usually located in the skid of the helicopter.