Range on WiFi... Technical question.
2919 11 2018-4-9
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Avian
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South Africa
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In open, farmland area I easily get 3km range on my Air, yet in a congested, built up urban area, I hardly reached 500m with VLOS before I lost signal.

I am confident there are a few 2.4 Ghz WLAN around as it's smack residential area surrounding from the field where I flew.

My question is this,
1.can these surroundings affect your range on a wifi signal so severely vs the rural area?

2.Do wifi signals dissipate so much with building trees and other things in built up areas vs rural areas?

3. Would a wifi signal travel further over land or water?

2018-4-9
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Kotsev
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Bulgaria
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Right, so let me try to answer these questions purely from technical point of view:
1) In urban areas all wireless communications (AM/FM Radios, Cellular, 2.4GHz/5.8 GHz networks, BlueTooth, Tetra etc.) have influence. On theory they work on different frequency but still there is some interference with the modules that transmit or receive them. Most commercial home based wireless routers use 2.4 GHz and I strongly recommend to use the 5.8 GHz band. It's very likely that this band is less loaded (less stacked devices using this frequency) and theoretically you should have better performance. Most likely you are aware that in the DJI Go 4 app for example, in the Wi-Fi section you have channel load for both 2.4GHz/5.8GHz. My drone switch them automatically when one of the two is overloaded however for best performance I recommend 5.8GHz band.
2) Wireless signals are interrupted also by any object in their way. The grater density the object has the more signals are lost passing through it. Now when two wireless devices communicate between each other they communicate in a straight line so if you have a huge concrete block of flats in front of you with 10 concrete walls inside it your signal will get very bad and most likely you will loose connectivity if you go on the other side.
3) On theory there should not be any difference. As I said wireless devices communicate between each other in a straight line so unless you are piloting a submarine drone it should not make a difference. Now there are few exceptions of course like if you are flying over the North/South pole for example.

Personal advise is to be very careful in urban areas. My aircraft is loosing connectivity frequently in the park which is based in the center of the city. There are no wireless networks around but have few cellular and TV broadcasting stations around. Always set your RTH and make sure you've also set up RTH attitude grater than the highest object you fly close to. Hope my comment was helpful! Cheers!
2018-4-9
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DJI Diana
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Kotsev Posted at 2018-4-9 12:41
Right, so let me try to answer these questions purely from technical point of view:
1) In urban areas all wireless communications (AM/FM Radios, Cellular, 2.4GHz/5.8 GHz networks, BlueTooth, Tetra etc.) have influence. On theory they work on different frequency but still there is some interference with the modules that transmit or receive them. Most commercial home based wireless routers use 2.4 GHz and I strongly recommend to use the 5.8 GHz band. It's very likely that this band is less loaded (less stacked devices using this frequency) and theoretically you should have better performance. Most likely you are aware that in the DJI Go 4 app for example, in the Wi-Fi section you have channel load for both 2.4GHz/5.8GHz. My drone switch them automatically when one of the two is overloaded however for best performance I recommend 5.8GHz band.
2) Wireless signals are interrupted also by any object in their way. The grater density the object has the more signals are lost passing through it. Now when two wireless devices communicate between each other they communicate in a straight line so if you have a huge concrete block of flats in front of you with 10 concrete walls inside it your signal will get very bad and most likely you will loose connectivity if you go on the other side.

Useful information, thanks for sharing.
2018-4-9
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Kotsev
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DJI Diana Posted at 2018-4-9 18:54
Useful information, thanks for sharing.

Very welcome Diana! I am more than happy to help a fellow drone pilot!
2018-4-9
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LindiSopaj
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just curious... does this apply for the Mavic Pro?

Considering returning my Air and getting the Pro. Ive only had my air for one day and one flight but I already go stutters in the video feed at only 40m height and 5m distance. Not acceptable
2018-4-10
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Avian
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LindiSopaj Posted at 2018-4-10 10:32
just curious... does this apply for the Mavic Pro?

Considering returning my Air and getting the Pro. Ive only had my air for one day and one flight but I already go stutters in the video feed at only 40m height and 5m distance. Not acceptable

Hi.

In which country do you stay. And is this with the controller.?

How does your surroundings look like...
2018-4-10
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Kotsev
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LindiSopaj Posted at 2018-4-10 10:32
just curious... does this apply for the Mavic Pro?

Considering returning my Air and getting the Pro. Ive only had my air for one day and one flight but I already go stutters in the video feed at only 40m height and 5m distance. Not acceptable

It really depends on your surroundings. As far as I know - the Mavic Pro has better performance in range perspective indeed but from what I read looks like you are flying in a frequency loaded area. Buying Mavic Pro might improve this but I would not rush this decision. I have Mavic Air myself and indeed from time to time my video feed gets gray and I loose connectivity but I can see on the Wi-Fi settings that the area and bands are overloaded. In general I am happy with the range of the Air. Please share some more info on how the location you fly at looks like?
2018-4-10
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LindiSopaj
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Avian Posted at 2018-4-10 20:25
Hi.

In which country do you stay. And is this with the controller.?

look at my second post you and kotsev asked the same thing So Ill answer both
2018-4-11
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LindiSopaj
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Kotsev Posted at 2018-4-10 20:55
It really depends on your surroundings. As far as I know - the Mavic Pro has better performance in range perspective indeed but from what I read looks like you are flying in a frequency loaded area. Buying Mavic Pro might improve this but I would not rush this decision. I have Mavic Air myself and indeed from time to time my video feed gets gray and I loose connectivity but I can see on the Wi-Fi settings that the area and bands are overloaded. In general I am happy with the range of the Air. Please share some more info on how the location you fly at looks like?

Im flying in sweden, not really the biggest city but I guess dense?

First flight was close to a university, id say the university was 300m away from me, and about 100m away I had some energy company, not quite sure what they do but one tall smoke thing and some water pools.

On the 2 other directions I only have regular apartments, after the park that is, Id say 300m away there aswell.

Second flight was on a football field, artificial grass dont know if that makes any difference with the concrete under it. about 200m away a park, and another 200m away another direction was regular apartments once again, this is the only time I got actual "singal interference" message.
The first flight only had some minor stuttering.

Third flight was close to a lake, a big one, behind me was a bunch of apartments and a rail road, this one actually worked fine except the winds were strong and I got a message telling me to be careful, so I didnt rly go that far out.

All these flights had some minor stutters in the video feed. With that I mean the video lags for 1sec and goes back, no error messages or anything like that. Maybe thats normal? I might just be really scared.

No grey screen so far and as I said only "strong aircraft interference".

Can I calibrate my compass again? I dont have that option and Id like to redo it since I did it on the location of my first flight, which wasnt the best, still says okay tho.

My IMU has not been calibrated, dont have an option to do so it just says "normal"

All in all I guess the question is, is minor stutters in the video feed normal? And can I rely on RTH if I loose connection?

I really like the drone but I dont want to constantly feel like I can loose connection at any time,

Worth mentioning, max height on all these flights has been 50m and 10-20m distance... which isnt that   far.

Thanks and sorry for the super long answer, just a student that is afraid of loosing a really expensive drone, from my perspective xD
2018-4-11
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Kotsev
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LindiSopaj Posted at 2018-4-11 15:52
Im flying in sweden, not really the biggest city but I guess dense?

First flight was close to a university, id say the university was 300m away from me, and about 100m away I had some energy company, not quite sure what they do but one tall smoke thing and some water pools.

Hey, no worries - I am also afraid for my aircraft and always flying with care. Reading your post above I would say the areas are not that much loaded in my opinion. The only possible problem I see is the electrical company as how you describe it it sounds like either a water power plant or (hope not the case) small NPP (Nuclear Power Plant). I would say don't attempt to fly over it as there might be some local regulations forbidding this and you can get yourself in to some serious trouble. Now regarding the rest - inside the forum there are a lot of topics for flight pre-check lists. Some of them are quite serious and long which in my opinion are not for hobby pilots like me and you and more for professionals using the drones for commercial purposes. I would recommend if you are flying in a new area always perform the compass calibration. When you start your DJI GO 4 app and after you are connected to the drone you get a screen describing the overall status of the aircraft. Make sure you are running latest firmware and that you don't see any errors. Afterwards press the calibrate button making sure you don't have any big metal objects near you and that you are holding your drone at least one meter from the ground. Make sure that your home point is properly updated (you can view it on the map) and also make sure in the app you have set attitude for RTH grater than the tallest object in the area you want to fly. I personally experienced only one emergency RTH. I was flying over a river and about 1 km away I've lost connectivity. I've missed few heartbeats but then after few minutes my aircraft landed in my feet. When you want to take your bird away from you make sure you will have enough battery for return to home and note strong winds might slow you down. The image freeze is normal and it really depends on a lot of things. Sometimes I have image freeze on 10 meters and sometimes I don't get it till 2+ km away. In any case don't panic if you loose connectivity and your image becomes green for a second or you loose video feed. I found useful for me that when I see my image starts to freeze and my drone is not very easy to steer and see where I am - I switch the live view to map view then I slowly navigate the drone to point to me and fly straight ahead. It's better than to panic and press the RTH. Also make sure your obstacle avoidance is always enabled! DJI have put big effort making their products smart and idiot proof so if you are not trying extreme stuff it's very unlikely to crash or loose your drone. Just don't do stuff you are not confident to do. After few hours in the air you will feel more confident and I fully understand what you mean that this is quite expensive toy. Wish you luck!   
2018-4-11
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LindiSopaj
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Kotsev Posted at 2018-4-11 23:13
Hey, no worries - I am also afraid for my aircraft and always flying with care. Reading your post above I would say the areas are not that much loaded in my opinion. The only possible problem I see is the electrical company as how you describe it it sounds like either a water power plant or (hope not the case) small NPP (Nuclear Power Plant). I would say don't attempt to fly over it as there might be some local regulations forbidding this and you can get yourself in to some serious trouble. Now regarding the rest - inside the forum there are a lot of topics for flight pre-check lists. Some of them are quite serious and long which in my opinion are not for hobby pilots like me and you and more for professionals using the drones for commercial purposes. I would recommend if you are flying in a new area always perform the compass calibration. When you start your DJI GO 4 app and after you are connected to the drone you get a screen describing the overall status of the aircraft. Make sure you are running latest firmware and that you don't see any errors. Afterwards press the calibrate button making sure you don't have any big metal objects near you and that you are holding your drone at least one meter from the ground. Make sure that your home point is properly updated (you can view it on the map) and also make sure in the app you have set attitude for RTH grater than the tallest object in the area you want to fly. I personally experienced only one emergency RTH. I was flying over a river and about 1 km away I've lost connectivity. I've missed few heartbeats but then after few minutes my aircraft landed in my feet. When you want to take your bird away from you make sure you will have enough battery for return to home and note strong winds might slow you down. The image freeze is normal and it really depends on a lot of things. Sometimes I have image freeze on 10 meters and sometimes I don't get it till 2+ km away. In any case don't panic if you loose connectivity and your image becomes green for a second or you loose video feed. I found useful for me that when I see my image starts to freeze and my drone is not very easy to steer and see where I am - I switch the live view to map view then I slowly navigate the drone to point to me and fly straight ahead. It's better than to panic and press the RTH. Also make sure your obstacle avoidance is always enabled! DJI have put big effort making their products smart and idiot proof so if you are not trying extreme stuff it's very unlikely to crash or loose your drone. Just don't do stuff you are not confident to do. After few hours in the air you will feel more confident and I fully understand what you mean that this is quite expensive toy. Wish you luck!

Thank you!

I dont have the option to recalibrate my Compass or IMU, it just says normal or whatever.

I'll give my drone a few more days, after all I have 30 days but Im really tempted to just get the Mavic Pro at this moment, occusync (never tried it) seems far more superior.
2018-4-12
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cspain
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United States
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LindiSopaj Posted at 2018-4-12 18:03
Thank you!

I dont have the option to recalibrate my Compass or IMU, it just says normal or whatever.

Are your antennas perpendicular to the aircraft? Are you pointing at the aircraft (use radar view in DJI go assuming you calibrated both the aircraft and your phone compass). Try flying a little higher.
I can get well over a mile range even with trees in the way (though this is out in fields and not near buildings).


2018-4-14
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