The circular polarization directional antenna, high gain, ideal for use in the video receiver when intending long ranges. They have a minimum of 12dB of gain, and combined with a Skew Planar Wheel Antenna in the video transmitter offers outstanding range results.
The antennas are right hand circular polarization, supplied with SMA connector, and including three different adapters, in order to allow different ways of connecting the antenna to the receiver.
The reflector is 3mm aluminum, the support structure is made of Plexiglas and 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.
A huge band width (as expected of a Helical). A Return Loss < -13dB is warranted across this frequency range, which means than >95% of the power is coupled to the antenna.
OPPOSITE POLARIZATION REJECTION
DIRECTIVITY - Gain of 12.33dB, with a beam width of about 60 °:
This is especially important in circular polarization. In a simple way: the difference between co-polar component (right hand circular in this case) and cross-polar (left hand circular) is the attenuation that will introduce the antenna to capture the reverse polarization, which will come from the reflected signal that we want to avoid to reduce multipath. In these antennas is bigger 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 that it interferes with the desired signal.