Is there a limit to the maximum number of herelink units thats can be operated in close proximity?
For example a dual operator setup with herelink would mean 2 herelink units per UAV and lets say I have 16 UAVs, thats a total of 32 herelink units. If I were to fly these in close proximity (5m apart) to each other would there be any intereference?
Also would having two herelink units (one for UAV and one for payload) on the same UAV have any interference with each other.
assuming stock settings the bandwidth is 20mhz, and using the entire 2.4ghz range, that would be 5 “channels” assuming you are using a lot of TX time (ie transmitting data).
i cannot 100% say, but i dont think 32 herelinks in realy close proximity would work that well. you could however change the bandwidth down from 20mhz to say 10mhz, and get alot more potential for links. (with lower thoughtput)
ive not tested any of this, just working from the numbers.
Thanks for the quick reply. The herelink will have a live video feed so it should use quite a bit of TX time. The 5 channels would mean effectively you can only have 2 UAVs (Dual herelink per craft) flying at the same time correct?
@Michael_Oborne revisiting this here.
We had 4x Harris Aerial aircraft’s planning a swarm mission. Had 4x Herelink Controller connecting to 4 of the aircraft’s.
For some reason we couldn’t keep the aircraft’s running in their missing much as they kept constantly RTLing from RC Link Loss.
We flew 2 aircraft’s and had no problems at all with aax range of 3km.
Decided to turn on a 3rd aircraft for testing, and suddenly as soon as the 3rd aircraft was powered the herelink video transmission started to glitch.
So coming down to @chandruth26 question. Would this mean that, I can effectively only run 2 aircraft’s at a time?
Previously we flew 3x aircraft, but at much closer proximity, within 1.5km without much issue. Yes the video feedback was a little glitchy, but managed to get through without RTL. But on these long range missions, constant RTL issues.
In the USA the 2.4ghz band is from 2.400-2.473 so to get no overlap between channels you only get 4 full 20mhz channels. however if you move to 10mhz bandwidth, you can increase this up to 7 channels. this is changeable via the settings app, but does half the available bandwidth, video should work fine like this however.
regarding the overlap, if your not tx’ing video, then you can have more on those same channels, as the duty cycle will be less. so just depends on your use case
also make sure you have space between the ground side units… as if they are too close they can interfere with each other, even if they are on other channels, via overpowering the front end RF ic’s
18mhz center freq
Thank you for that. When you meant the ground unit are close, what is the recommended distance between them?
I have reduced the DL BW from 20 to 10 and we are able to get 3 aircraft in the air, but the video is horrible.
I am suspecting this is because the video is at 1080p. Now when I change the resolution from the Herelink Controller drop down, from 1080p to 720p, is that changing the actual transmission resolution or the played back quality? I believe if I can transmit at a lower resolution, I would get a better video quality as less bandwidth is taken up, and also possible include another 2 aircraft to get us 5 aircraft for Swarm.
DL BW to 10 UL BW to 10, and untick Hopping
then in Freq,
Set 1 to 47105
set 2 to 47205
set 3 to 47305
set 4 to 47405
as for video quality, it shouldn’t be that bad at 10mhz BW, what does the uplink bandwidth say on the radio, should be around ~8000 at close range
Thanks for the quick response. I will have to get back to you on this one, as we are now in operations and I don’t have the aircraft to test this out. But indeed, looks like a good idea to try with the frequency hopping turned off. I will update back here when I have more news. Cheers