Hi there. Can someone let me know what the function on the left and right antenna is on the remote controller? I assume one is for video information and the other is for RC controls and other telemetry?

Is there any reference information on this I can refer to?

Hi, thanks for the inquiry. We will check this information with our team for further clarification and to see if we could provide a reference for your query. Please let us know if you have other concerns. Thank you for your support.

Why do you ask?

My guess, both antennae carry the same signal.

the video is normally a separate antenna from the control or data stream antenna ,if your thinking high gain antennas you will need to change both

Technically, two antennas will create a directional pattern, focusing the RF signal forward & back between the 'antenna stack', unless you have a reflector behind the antenna to reflect the signal forward. That's why they say to face the antennas toward Spark. Compared to a single antenna, a 3db gain (double the signal) may be achieved in the required direction with two antennas.
A single antenna will be omni-directional, depending on the ground plane & wavelength, the focus of the RF signal will still be 360 degrees horizontally, but may be reduced vertically. (or vice-versa, based on orientation)   However a single co-linear antenna, depending on the number of phase elements, may achieve similar results, but will be physically longer - basically another way to stack antennas which will also focus the signal. Another option is the Yagi style antenna (also called a beam) - like a TV antenna.
Truckies used to have two CB antennas, one on each mirror. The signal would be strongest in front & behind the truck. No need for separate antennas for video/control if they are tuned within the bandwidth required. The main purpose is to create a directional signal, otherwise there would be no need to face the antennas 'forward' towards Spark as the signal would otherwise be 360 degrees.  Therefore, the antennas are 'stacked' & receiving the same info on each one.
Just remember, the higher the gain, the more directional the antenna will be. For example we can make a 12 db antenna, but it may have a 22 degree focus, or use a 6 db antenna & have a 45 degree focus. Imagine a torch/flash light with an adjustable reflector. Focusing the reflector will produce greater/brighter light in a smaller area, but travel further. Take away the reflector & light will spread in all directions, but not as bright.

Google "RF wifi antenna directional omni directional yagi stacked antenna" etc for references.
Example:
https://blog.solidsignal.com/tut ... acking-really-work/
https://www.allaboutcircuits.com ... nal-wi-fi-antennas/

As the third post said "Why do you ask?"

Proteous Posted at 1-28 18:55
the video is normally a separate antenna from the control or data stream antenna ,if your thinking high gain antennas you will need to change both

Terrestrial TV/Radio or Satellite may use a single antenna/dish for several frequencies at the same time. The antenna does not care. Each signal is basically AC (alternating current) and can be mixed together & separated at the other end. Think about network powerline adaptors.
Unless a different frequency out of tune from the antenna bandwidth (HF vs VHF vs UHF) is to be received, a single antenna can be used. The RC is 2.4 or 5 Ghz  so a single antenna can be used. 5 Ghz is close enough enough to half the wavelength or 2.4.  The 2.4 Ghz reception may be a full wavelength, whilst the 5 Ghz will be half a wavelength. Both will comply with a reasonable S.W.E.R .

Sparkz71 Posted at 1-29 05:14
Terrestrial TV/Radio or Satellite may use a single antenna/dish for several frequencies at the same time. The antenna does not care. Each signal is basically AC (alternating current) and can be mixed together & separated at the other end. Think about network powerline adaptors.
Unless a different frequency out of tune from the antenna bandwidth (HF vs VHF vs UHF) is to be received, a single antenna can be used. The RC is 2.4 or 5 Ghz  so a single antenna can be used. 5 Ghz is close enough enough to half the wavelength or 2.4.  The 2.4 Ghz reception may be a full wavelength, whilst the 5 Ghz will be half a wavelength. Both will comply with a reasonable S.W.E.R .

>Why do you ask

Firstly just to see if @DJI Tony will respond with his offer to find out for me (no Just kidding Im sure hes working on it). The DJI guys do a great job here.
The real reason is just to learn more about the controller. I guess the more I know about the technology the less likley I am to part with my drone.. As you can see some people think the antennas are for uplink and downlink. But I think the correct answer is they both transmit the same signal.  

bugalugs22 Posted at 1-30 22:46
>Why do you ask

Firstly just to see if @DJI Tony will respond with his offer to find out for me  (no Just kidding Im sure hes working on it). The DJI guys do a great job here.

I didn't think too hard. Combining a 2.4 & 5 Ghz antenna (full wave vs half wave vs 1/4 etc) is simple.  
Next is harmonic interference.  Example - https://whatis.techtarget.com/definition/harmonic
The same signal may be received/crossed within 1/2 waves or 1/4 or 1/8 etc.
It's too technical to explain more. But for example, I have had many problems with the old TV - 210 Mhz TV caused interference with 105 Mhz FM radio, vice versa.   The solution is to install a filter & reduce the unwanted frequency. But, obviously this is not simple within the RC as the 'feed' is built into the RC.
How technical do you wish to learn?