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My P4 Range Tests
2002 33 2016-9-17
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MD_Icarus
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I want to state at the onset, that these results are not only preliminary, and they are based upon ONLY ONE  of each of the following: P4, RC, Antenna Mod.

That means, that my results, may not match your results, because the 4 variables I listed above have tolerances, and yours may have different performance characteristics than mine. A good test will sually inlcude a few of the above to see if it is consistent.  There is another critical factor in my opinion, and that is temperature.  All these tests were performed at relative lower temperature of 70° - 80° F.

So far, the first week I devoted to just Distance testing, flying over the ocean, with clear eye view of the P4 throughout the flight.
Why did I do this? I am not looking to break any records, I just wanted to get back to what I was enjoying when I first flew the P4 from factory back in May.  I used to get about 1.5 - 2  and clear video streaming.  Then recently, the range was redulced to 0.7 - 0.8 , and my video streaming was extremely laggy and I had constant green screens.

1) Using the copper parabolic range booster my range increased to about 1.2 - 1.4  and the video streaming improved, but I was still getting some green screens. The video streaming was affected by the ambient temperature; when it was above 90°, I used to get more green screens.

I then proceeded with an RC Antenna mod; I tried the 2 most popular mods in the market right now.  I prefer not to mention the names, but it will be obvious to anyone which ones I am talking about.  I did not use any active amplifiers, because I believe they will introduce noise and cancel any additional gain anyway. I also do not like noise around the RC, when there are high frequecy signals at low power.
I performed 1.2, 1.5, 1.9, 2.2, 2.5 tests.  

And I am happy to say, that both antenna mods provided the same exact results at all those range tests.  The minimum RC signal strength was recorded at 95%/94% using both mods.  I was surpised to see how close they both operated.  I am happy with the 2.5 range, and I do not plan to push them any more, although I think they can go further.

One important apsect is that these were all straight flight tests.  All I had to do is keep the RC pointing in one fixed direction. I have not yet tested them using wider flight routes, or see how they penetrate structures like trees, etc.
My video streaming was more or less perfect in all test flights. Only when the P4 turned a few times, I would see some minor lag.
Of course I use a light beacon so I can see the P4 throughout the flight; plus I have an acute eye sight, which may be the result of having a glass of carrot juice every morning since I was 5 and the only cake I eat is carrot cake.

So far, my tests show that they work.  They are not gimmicks, as some may have felt.








2016-9-17
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Aardvark
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"So far, the first week I devoted to just Distance testing, flying over the ocean, with clear eye view of the P4 throughout the flight."

I'm curious as how you managed to have sight of the P4 at 1.2 miles let alone 2.5 miles ? What would you do if a coastguard helicopter appeared, CSC or hope for the best ?
2016-9-17
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Cetaman
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Aardvark Posted at 2016-9-17 09:19
"So far, the first week I devoted to just Distance testing, flying over the ocean, with clear eye vi ...

Aloha Aardvark,

     Near the end of his post, he says, "Of course I used a light beacon so I can see the P4 throughout the flight;"  Then he notes the merits of carrot juice and carrot cake and the benefits to sharp eyesight.

Aloha and Drone On!
2016-9-18
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Cetaman
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Aloha Icarus,

     Good to see you are having positive results.  Unfortunately, I got blown out and rained out today.  I will try again tomorrow.  I will be doing unassisted distance tests with my P4 facing the four directions and see the pixilation results.

Aloha and Drone On!
2016-9-18
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MD_Icarus
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Cetaman Posted at 2016-9-18 04:55
Aloha Icarus,

     Good to see you are having positive results.  Unfortunately, I got blown out and ...

I understand how that can be; I was grounded for a week due to storm activity.

But my iphone 6p is not lagging any more using the antenna mod.

There is an additional main variable though in the analysis, which makes the conclusion harder:
The temperature has moved from 90 to 70 in a few weeks.

As far as eyesight, This is the science behind it:
"The brightness of a candle flame, and the way a glowing object dims according to the square of the distance away from it, vision scientists conclude that one could make out the faint glimmer of a candle flame up to 30 miles away."

Human-scale objects are resolvable as extended objects from a distance of just under 2 miles (3 km). For example, at that distance, we would just be able to make out two distinct headlights on a car.
Always test in a darker cloudy day or evening.


The main limitation is the earth curvature at 3.1 miles away.





2016-9-18
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MD_Icarus Posted at 2016-9-18 03:00
I understand how that can be; I was grounded for a week due to storm activity.

But my iphone 6p is ...

Aloha Icarus,

     You are preaching to the choir here.  Many years in sensory sciences keep me amazed.  The light beacon is a good idea for the reasons stated.  

     The wind is a little stiff, but since my tests will be with antennas unassisted, the distances will be short, if it is still acting up.  But, as always, I expect that my P4 may just behave today because I am watching it closely.  Kind of like your car starts to behave when you take it in to the mechanic.  Or, I did luck out recently when I had my electrician come over to see about some intermittent problems I was having at my house.  Now that is a clear and present invitation for the house to behave as soon as the electrician gets here.  But, the light in the circuit breaker room dimmed and cinched the deal - house busted!  Hawaiian Electric came and fixed a problem with my connection with the pole - no cost, problem fixed!  I like happy endings!

Aloha and Drone On!
2016-9-18
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MD_Icarus
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Cetaman Posted at 2016-9-18 18:42
Aloha Icarus,

     You are preaching to the choir here.  Many years in sensory sciences keep me a ...

Does your Nvidia have GPS? I assume it does not come with a phone plan available, so are you planning to use your phone as a Hotspot so you can get maps?
2016-9-18
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Bond
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I've received max 1200 feet before lost transmission and rth initiates, and I fly in flat as a pancake Florida, what happened to 2 miles? Suffice to say my nads were in my throat as this was only a week in..
2016-9-18
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MD_Icarus Posted at 2016-9-18 14:04
Does your Nvidia have GPS? I assume it does not come with a phone plan available, so are you plann ...

Aloha Icarus,

     nVidia does indeed have GPS in the form of Android Locations.  You even get GPS read-outs.  Phone plans have to be forced on nVidia Shield K1 devices currently, but it can be done.

     I have always used my Samsung Galaxy S III as a Hotspot when in the field.  At home I use my WiFi.  But, my Galaxy Tab Pro has been my work horse for DJI GO in the past.  

     Now for today's results.  Pixilation and green pages have nothing to do with distance.  Using my native antennae and flying around above the jungle resulted in no preferences relating to antennae direction or distance.  Flying up into the mountains also resulted in no preferences relating to antennae direction, but the same green pages and pixilation events occurred and they occurred at the same rate.  Most of the time I had good reception, certainly good enough to fly according to my needs.

     On a second set of experiments, we tried the parabolic range extenders and all aspects improved considerably but pixilation was not completely removed.  OK, why is that?  I am completely open to ideas and have the means to test them.  Meanwhile, I am having fun with my P4 and the occasional weird display.

Aloha and Drone On!
2016-9-19
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rliamharpurb
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Here in the U.K. Countryside I've only gone 1.7 miles still with full signal on everything, couldn't go any further as was cycling a new batter to 50%

I reckon in the same location I could get Atleast 2.3 miles

Will give it a try when I get chance but I am confident you can reach the advertised distances easily if flown in the correct location
2016-9-21
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rliamharpurb
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And I only expirience green screens when it's really hot and my iPad Pro is warm
2016-9-21
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peter12
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You guys are talking about miles?
Here is my Range Test... 8 kms

2016-9-21
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rliamharpurb Posted at 2016-9-21 06:07
Here in the U.K. Countryside I've only gone 1.7 miles still with full signal on everything, couldn't ...

Hi, I'm in the UK too suffer with the green screen of death and flickering of in out signal even when out in the wild on top of a hill and just want to fly to the top of another.. its very unstable in that sense. At least I now know that its just live video stream and not flight control as that seems solid as a rock but all my recorded footage is plagued with full speed ahead to sudden standstill as I wait for signal to reappear and my ass to close in the terror that my bird is about to fall onto a nursery from up high and behead a flock of babies. I wish DJI or someone would just sort this out as it is a very unnerving "feature"!   
2016-9-21
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dj.trillium Posted at 2016-9-21 13:19
Hi, I'm in the UK too suffer with the green screen of death and flickering of in out signal even w ...

All your recorded footage should be on the SD card in the Quad and unaffected ?

Which display device are you using ?
2016-9-21
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Aardvark Posted at 2016-9-21 08:24
All your recorded footage should be on the SD card in the Quad and unaffected ?

Which display dev ...

My video footage is affected because as soon as I get a signal disconnect I physically kill the throttle in fear of something going wrong. Nothing probably will but its hard not to react when signal is lost.

I use iphone 6 and an Ipad pro 9.7 inch and both show the affects in the same way. I should have made a note of when it first started to happen to make fault finding easier but I didnt. Here's hoping the next sw update improves things.
2016-9-21
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peter12 Posted at 2016-9-21 06:44
You guys are talking about miles?
Here is my Range Test... 8 kms

Ive not heard the audio but it looks like you had weak signal warnings for a good duration of that flight but no green screen interference etc. good job I guess as you were a good distance away!
2016-9-21
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dj.trillium Posted at 2016-9-21 16:38
My video footage is affected because as soon as I get a signal disconnect I physically kill the th ...

What sort of range does it start to have problems ?

You do have hardware decoding on, and auto channel selected for the video ?

2016-9-21
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MD_Icarus
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I use an iphone 6p and I experienced constant green screens when the temp was in the 90's. It has improved a lot recently, wile the temperature now is in the 70/s,

So I am convinced that high temperature affects streaming video performance.  I did tests with the P4 inside an air conditioned room and my iphone outside under the hot sun, and it was so hot, my iphone went off due to heat; but my video was good.  But when the P4 was under the hot sun, I was getting green screens. The p4 was not flying when I performed this test though, so maybe when it flies, it cools down a bit.

Maybe drilling holes in the front/back of the cover to increase ventilation??? Where is the video transmission board? Adding a slob of metal heat sink?  External fan?
2016-9-21
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Aardvark Posted at 2016-9-21 23:54
What sort of range does it start to have problems ?

You do have hardware decoding on, and auto cha ...

It starts from 10m + and is just on and off from there onwards with hw decoding and auto channel selected.. I'm in the UK so have absolutely no issue with running the p4 in hot weather, 60 - 80 degrees if we are lucky. I've tried multiple USB leads and memory cards with no change so it's quite frustrating. I should get my new iPhone 7+ in a day or 2 so I'll just keep plodding on trying to illiminate things in the time we have left here until it will be time to pack it away for our 7 month bloody winter. Perhaps in that time DJI will release a few more updates to improve.. we'll see.
2016-9-21
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dj.trillium Posted at 2016-9-22 00:07
It starts from 10m + and is just on and off from there onwards with hw decoding and auto channel s ...

Have you tried relinking your copter to the RC, or a firmware refresh and factory reset may help ?
2016-9-21
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peter12 Posted at 2016-9-21 18:44
You guys are talking about miles?
Here is my Range Test... 8 kms

It was like watching a suspense movie.  I think I was as nervous as you were.  A 6332 foot drop across 5 miles, nice!
2016-9-21
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MD_Icarus
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Cetaman Posted at 2016-9-19 09:02
Aloha Icarus,

     nVidia does indeed have GPS in the form of Android Locations.  You even get GP ...

In my case, I went from very bad video streaming (constant green screens) to almost perfect video now by:

1. Using an antenna mod
2. The temperature is now in the 70's.

Everything else is the same as before.

Does your pixelation become worse after you fly for about half the battery life?
2016-9-21
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MD_Icarus Posted at 2016-9-21 17:58
In my case, I went from very bad video streaming (constant green screens) to almost perfect video  ...

Aloha Icarus,

     Not really.  Actually, I am only flying for 50% of the battery for the first ten charges.  (I think it was DJI-Ken who said 50% for first 10 charges will lengthen the lifespan of the battery.)  I am now at 10 charges and can fly full battery.  

     My pixelation still seems random, but I have discovered that my live feed video resolution is way below 720p, more like 360p-480p.  I am trying to get screen shots tomorrow for DJI-Natalia (today I had a meeting).  Even the parabolics only get me low resolution.  But, my P3P gives me full 720p resolution using all three different displays (nVidia, Galaxy and HeadPlay).

     Oh, BTW, I thought the nVidia Shield K1 HDMI port would give me a better live feed video than the DJI HDMI module because nVidia specializes in display cards and software.  But a head to head comparison showed clearly that the DJI HDMI module gives a significantly better 720p live feed.  Hmm, interesting.

Aloha and Drone On!
2016-9-21
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Cetaman Posted at 2016-9-22 03:49
Aloha Icarus,

     Not really.  Actually, I am only flying for 50% of the battery for the first t ...

I meant to ask is the video worse when the battery level is below 50%? That would mean your P4 is warmer then. That was the first think I noticed, it was great during the initial few minutes, and degraded later.
2016-9-22
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peter12 Posted at 2016-9-21 06:44
You guys are talking about miles?
Here is my Range Test... 8 kms

I would never attempt such a stunt!

First it is not legal in most countries, if not all,

What if you were not lucky and did not regain video back while you were flying over the town?  The P4 would have landed somewhere and you would have hoped you were lucky again, it did not land on top of someone or someone's property.

Other than that, it was a great stunt!
2016-9-22
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MD_Icarus Posted at 2016-9-22 07:40
I meant to ask is the video worse when the battery level is below 50%? That would mean your P4 is w ...

Aloha Icarus,

     That can actually be tested now since I will be running my P4 batteries below 50%.  

     Try to check your video resolution on the live display of your P4 with your live display of your P3.  If you can have them right next to each other that would be best (if they do not interfere with each other).  I am wondering if those of us who get green screens are also getting 480p resolutions and just ignoring it.  I used to ignore it because I had too many other problems.

     This could be explained by a mix-up during component assembly during manufacture.  The P3 4K has a 480p resolution.  If when the P3 4K camera, and transmitter support (WiFi actually), is being assembled, there is a part that controls the resolution (480p) that looks just like the part that is in the P4 that controls resolution (720p), they could get mixed up on a very limited basis.  If our P4s were manufactured with the resolution component from the P3 4K, then our cameras would transmit live view with a 480p resolution.  And since the P3 4K resolution component was not designed to be used with the P4 there would be other artifacts that indicate the wrong resolution component was installed.  The green screen seems to be exclusive to those of us with the severe pixelation and range issue.  

     The resolution problem, along with the severe pixelation and range problem are all major differences between the P3 4K and the P4.  The manufacturing mix-up would be explained if the part looks similar between the P3 4K and the P4.  It would not be noticed easily by assembly workers and inspectors.  And since the P4 still flies and provides great recorded video and the live view is just messed up but not so severely messed up that it affects flight, testing might pass the P4 for distribution.  

     I get some very minor pixelation with my P3P when there are transmission problems, so pixelation is an indication of a "normal" problem that is not severe.  But, we get severe pixelation that is an indication of a severe problem.  The fact that we can use range extenders to recover some of the loss caused by the mix-up shows that the reduced range of the P3 4K may be involved.  We already discussed the 480p resolution that I noticed.  But, the green screen is the real indicator.  I have never seen it in any other platform, only my P4 problem.

     So, what do you think?

Aloha and Drone On!
2016-9-22
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MD_Icarus
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Cetaman Posted at 2016-9-22 19:22
Aloha Icarus,

     That can actually be tested now since I will be running my P4 batteries below  ...

Interesting finding!

I checked my cached videos and they are 720p.

My video streaming is almost perfect now, as the weather has changed and we are now enjoying 70º (instead of 90º+).  I am also using an antenna mod, but the green screens were not a function of distance.

DId you test it in a cool room, right after it was having the green screens? I moved mine from outside inside a cool room, and the green screns went away after about a minute. I kept the iphone outside.

Did you find a short 1' cable which will fit the RC and the NVIDIA Shield?
(Yes I bought one too)



2016-9-22
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Cetaman
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MD_Icarus Posted at 2016-9-22 16:52
Interesting finding!

I checked my cached videos and they are 720p.

Aloha Icarus,

     Yes, interesting, but apparently wrong.  I did as Natalia requested and my screen shots were definitely 720p between the green screens and pixelation.  

     BTW, one of the perks of living on an island in the middle of the Pacific is the temperature - at least on the Windward side is 75 to 80 degrees steady.  (If it gets down to 60 in the Winter, we joke that someone towed the island to the mainland!)  Without parabolics, my pixelation and green screens are now way worse than when I first got my P4.

     Unfortunately, the cached videos do not necessarily tell a true story.  We regularly watch 720p, 480p and other resolutions as clips in 1080p videos and above.  The 720p only means that the clip resolution, whatever it was, was recorded in 720p.  I was hoping that would give us an answer, but then I watched some videos last night with lower resolution clips in 1080p and 1440 videos.

     The big discrepancies that led to the theory were when I was using my HeadPlay HD goggles.  I thought the goggles were just reproducing the 720p video, but it appears I was wrong about something.  The HDMI output to my goggles from the nVidia Shield K1 HDMI port was not even as good as the DHI HDMI module on the P4 and it was like 480p.  The HDMI module on the P3P on the other hand had a substantially better live video output.  I have to go back to the drawing board on this.  Fortunately, when things are this bad isolating the variables just takes time, but progress is steady.

     I will keep you posted.
2016-9-22
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MD_Icarus Posted at 2016-9-22 19:44
I would never attempt such a stunt!

First it is not legal in most countries, if not all,

If I would have lost signal, it would return to home. That means: it would first ascend up to the RTH altitude and then fly back. Anywhere during that process, I would get the signal back. Depending on the battery-level, I would have to decide what to do: retry or find a landing spot. I had decided already that I would want to retry 2-3 times depending on the battery-level. Furthermore I had already explored the area as well as in Google Earth, as by flying over it from a short distance, for a good 'emergency landing spot'.
So no, it would not just have dropped on somebody or something :-).
Even if I would completely have lost the signal and it wouldn't have had battery left anymore, it would try to LAND and not just fall out of the sky.
2016-9-23
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MD_Icarus Posted at 2016-9-18 14:00
I understand how that can be; I was grounded for a week due to storm activity.

But my iphone 6p is ...

Just a few comments, the distance at which is possible to see a candle and the acuity of a normal human eye depends strongly on the environment. To see a candle a 30 miles you and the candle  would have to be in a very dark spot away from city lights and in a moonless night plus your night vision, normally achieved after 30 minutes in complete obscurity,  will have to be perfect.
Regarding the resolving power of the eye or acuity, what you quote about the headlights even though it is correct, does not apply directly to a shape like a human body or a drone illuminated by the sun. In this last cases the resolution is  worst.

Finally, what I think is a very important aspect. As Peter12 mention at the end of his fantastic video, it is necessary to keep in mind that in a perfectly clear day with direct view to the drone, the opacity in short radio frequencies is mainly due to the water vapor between the transmitter and receiver. While in a dry atmosphere like that of the desertic part of Tenerife Peter was able to achieve 8km, I'm sure he would not be able to repeat that feat when back in the Netherlands.
Flying with humidity around 80% expect a much reduced maximum distance of operation.
2016-9-23
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peter12 Posted at 2016-9-23 05:43
If I would have lost signal, it would return to home. That means: it would first ascend up to the  ...

Your Critical Battery distance warning came early on in the flight, and although that warning tends to come on earlier to allow some tolerance for wind, there was no chance it would have come back home after you proceeded on.

So your only hope was to either manually land it somewhere, or it would have landed on it's own once the battery went to 10%.  I think you were lucky regaining signal because your position was at a very high altitude. That would not be the case for most of us controlling the P4 at ground level. Once someone tries to land it, they will lose signal and RTH will be initiated.

I would recommend that you consider using litchi for such stunts, because you can program it to hover above your roof, and thus in the event you lose signal it will land there, or you can land it manually, if you still have signal.
2016-9-23
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Heniek W
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peter12 Posted at 2016-9-23 03:43
If I would have lost signal, it would return to home. That means: it would first ascend up to the  ...

I believe what you could also do is half way there reset you home position right on your property,
this way if you lost and not regained your signal the return home point would be your flight destination location and the P4 would get there on it's own...
I am surprised how badly the mod was performing at 4km range, you can push through your bird upto 6 km with just stock antennas, the mod you got there seems disappointing...
Nevetheless this was a great achievement , congratulations on your long range flight !
2016-9-23
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Heniek W Posted at 2016-9-23 13:57
I believe what you could also do is half way there reset you home position right on your property, ...

How do you set the new Home Point to anything other than the current P4 location or your device location?
2016-9-23
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Heniek W Posted at 2016-9-23 19:57
I believe what you could also do is half way there reset you home position right on your property, ...

You can only set the homepoint to either the drone's CURRENT location or your own CURRENT location (if there is GPS on the phone/tablet).
But yes, what would have been possible is to select a new homepoint half way and continue from there. But I didn't want to lose time for that, because I didn't know whether the battery would last that long.
2016-9-23
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