I’ve not been able to find out how the DJI digital system actually works antenna wise. As many know the preferred antennas for analog video are circularly polarised. That’s because when a circular polarised signal is reflected (multi path) the polarisation is reversed, meaning right-hand becomes left-hand and vice-versa, and as the antenna is unresponsive to the opposite polarisation it only receives the direct signal and “mostly” rejects the reflected signal. This is why circular polarised omni antennas are used in preference to the linear dipoles, even though the circular omni-directional antennas have negative gain.
I have the Amimon Prosight System and at first glance it appears counter intuitive. With the Prosight digital FPV system a method known as MIMO, meaning Multi-Input Multi-Output, is employed. This is also used in many other digital systems with WiFi being one of them. Using this method the system is able to exploit the multi-path predominant in EHF and Microwave signals, so rather than being rejected the multi path component is utilised to increase the capacity of the link. On the Connex Falcore Quad I have there are two linear antennas on the Air unit, one horizontal and one vertical. The receiver has five antennas all vertically polarised. This was falsely interpreted by many users as a vertically polarised diversity system when in actuality they all work cooperatively as a single array, with both polarities being recombined in the receiver, effectively reducing the error rate and allowing for greater range with lower power levels. I was able to compare the Prosight system against an analog system, both using 25mW, the last time I flew at my club site. I was able to enjoy a crystal clear digital video feed out to a distance of around 800m where as the analog feed was plagued with breakup after about 300m.
I know that some DJI FPV users are using antenna arrangements similar to those we employ with our analog systems, directional and omni-directional as used on an analog diversity receiver, but if the DJI system is also employing MIMO this would be detrimental and possibly why many are pushing up the power levels of their goggles and air units.