Circular Wireless HELIAXIAL58 Helical Axial Mode 5.8 GHz FPV Antenna
This Circular Wireless Helical Axial Mode 5.8 GHz HELIAXIAL is a high gain, right hand circular polarized (RHCP) directional antenna, ideal for use with an FPV video receiver for achieving long ranges. With a minimum of 12dB of gain, this antenna combined with a Skew Planar Wheel Antenna in the video transmitter offers over 6 km of FPV range. Supplied with an SMA female connector, three different adapters are also included to allow different ways of connecting the antenna to the receiver at different angles. The reflector is 3mm aluminum, and antenna support structure is made of Plexiglas. The helix is made of enameled copper. The start of the helix runs parallel to the reflector: This is the impedance matching, and it has been adjusted manually for each individual antenna. This antenna features a huge bandwidth (as expected of a Helical; see reflection parameter chart). A Return Loss of less than 13dB is warranted across this frequency range, which means that >95% of the power is coupled to the antenna. Directivity: gain of 12.33dB, with a beamwidth of about 60 degrees (see directivity chart). Opposite polarization rejection (see copolar vs. crosspolar chart): This is especially important in circular polarization. Put simply: the difference between the copolar component (right hand circular in this case) and crosspolar component (left hand circular) is the attenuation of the captured reflected signal that we want to avoid to reduce multipath. In these antennas cross polar attenuation is greater than 10dB in all cases, which means that the reflected signal will reach the emitter attenuated at least 10dB with respect to the desired signal, which is great to prevent reflected signals from interfering with the direct signal during FPV.