Another possible reason for reports of P4 reduced range
2136 13 2016-4-14
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Jim Watkins
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Greetings friends,

I am not completely convinced that the Phantom 4 range issues have to do with the controller or it's power.  What I am starting to suspect is that the P4 receiver(s) in the aircraft are not as immune to interference and desensitizing in high RF environments as the Phantom 3.  I am in Burbank, CA, part of the Los Angeles area.  When I got my P4, I noticed that I was getting somewhat less distance than I had with my P3P and I have done some tests to try to determine why.  Tests comparing the range using my P3P controller with my P4 are so far inconclusive however, I may be seeing slightly better performance when using the P3P controller, but I'm not certain yet.

There is one direction I can fly from my home that takes me over the Los Angeles Equestrian Center, across the LA river and eventually into Griffith Park.  What's significant about that route is that I get much farther flying in that direction than in any other and after the first 2000 feet or so, you re getting into unpopulated areas.  Any other direction takes you over densely populated parts of the city and I typically get ranges around 3000 feet.  Yesterday I flew that route and when I took off, I got momentary video break up and weak signal a couple of times about 1500 feet from home while still over the densely populated part of south Burbank.  But as I began to get over less and less densely populated areas, moving further south over the Equestrian Center and eventually into Griffith Park, the signal became more stable even though I was getting further from home.  I eventually turned back at a distance of over 5400 feet from home and I could have gone further because the signal was solid even at that distance.  I did this flight standing on my back porch in densely populated Burbank.  So, I am starting to think that there may not necessarily be a transmitter power problem, but rather an issue with aircraft receiver vulnerability to localized interference.  That would explain good distance when flying over less populated areas, and not so good over densly populated areas even though the control point is still within a densely populated high RF environment.  Incidentally, all my tests were done at about 380' altitude.  Just my latest thoughts on this issue.

More info here https://en.wikipedia.org/wiki/Desensitization_(telecommunications)

FPV here

--Jim

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2016-4-14
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Kneepuck
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Likely, it is a combination of a number of things.  The P4,  like the P3 Advanced and Professional versions, uses 2.4 ghz for both control and video downlink.  You would be hard pressed to find a band in the radio spectrum that is more crowded. And even the 5.8 ghz band is beginning to get that way.  As more and more wifi devices come onto the system, the situation will only get worse. No amount of encryption will overcome sheer rf saturation of the spectrum.  An ( illegal ) solution is to use an amplifier.  This will increase the range, though your neighbors may not be too happy with the interference it causes in their wifi devices.  And the FCC would be very unhappy.
The only real solution is to use another frequency. spectrum. But that is problematic for many reasons.
2016-4-14
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microcyb
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Kneepuck Posted at 2016-4-14 16:02
Likely, it is a combination of a number of things.  The P4,  like the P3 Advanced and Professional v ...

Shhh, don't tell them about amplifiers, repeaters, etc.  {:2_38:}
Got to keep that stuff on the down low you know.Oh look Sunhans is having a sale!
2016-4-14
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R&L Aerial
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The phantom 4 has 20% less power than the phantom 3, I saw this on the FCC website with my own eyes but I also get what your saying. I use my inspire 1 pro c-model controller with my phantom 4 , it resolves any range issues I have.
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Morph1
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Tip: the author has been banned or deleted automatically shield
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Jim Watkins
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R&L Aerial  Posted at 2016-4-14 13:33
The phantom 4 has 20% less power than the phantom 3, I saw this on the FCC website with my own eyes  ...

One thing a lot of people don't understand about RF transmitter power is that it is a logarithmic scale.  You have to at least double the power output of a transmitter to produce a just barely noticeable improvement (3db) at the receiving end.  So a 20% decrease in power probably wouldn't make any detectable difference at all.
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minim
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Jim Watkins Posted at 2016-4-14 22:55
One thing a lot of people don't understand about RF transmitter power is that it is a logarithmic s ...

and if I'm not mistaken that was on the radio transmitter side also but people are mostly having problems with the video link that goes weak first and that's not related to the radio TX output at all ^^
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microcyb
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Morph1 Posted at 2016-4-14 16:37
can you please post a link to that information you claim you've seen...
are you honestly getting be ...

Do a google search ffcid phantom 3 or ffcid phantom 4
https://fccid.io/SS3-WM3301512
https://fccid.io/SS3

Equipment Class:
Digital Transmission System
Notes:
Phantom 4

Grant Notes FCC Rule Parts
Frequency
Range (MHZ)
Output
Watts
Frequency
Tolerance
Emission
Designator
CC MO15C
2406.5  -  2476.5
0.598


Equipment Class:
Digital Transmission System
Notes:
Phantom 3 Professional

Grant Notes FCC Rule Parts
Frequency
Range (MHZ)
Output
Watts
Frequency
Tolerance
Emission
Designator
MO15C
2406.5  -  2476.5
0.746

Equipment Class:
Digital Transmission System
Notes:
Phantom 3 Advanced

Grant Notes FCC Rule Parts
Frequency
Range (MHZ)
Output
Watts
Frequency
Tolerance
Emission
Designator
MO
15C
2406.5  -  2476.5
0.729

Equipment Class:
Digital Transmission System
Notes:
Phantom 3 Standard

Grant Notes FCC Rule Parts
Frequency
Range (MHZ)
Output
Watts
Frequency
Tolerance
Emission
Designator
MO15C
2412.0  -  2462.0
0.582


2016-4-14
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Morph1
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picro88
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No wonder i couldnt find his post. Its been deleted.

Myself and a few other people had asked DJI-Ken direct questions regarding this possible range issues on his post yesterday.
Im not sure why he would post a video saying the range is not a concern, then when asked questions, delete his post instead of assisting with the communites concerns.
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ArcticM39
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To support OP's suggestion...
I fly in an area without houses or any other major structure, other than a few dried up water tanks.
I get same range with P3A and P4.
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microcyb
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Morph1 Posted at 2016-4-14 16:54
Great find sir ! , yeah the controllers are exactly the same lol , Jeez ....  talking about honesty ...

Well that is his choice.  Sadly users could correct this hardware flaw without range extenders, etc, but suspect it still would void the warranty.
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rodger
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Just for the heck of it try it with your tablet or Phone in "Airplane" mode and see what happens.
2016-4-15
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rodger
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R&L Aerial  Posted at 2016-4-14 16:33
The phantom 4 has 20% less power than the phantom 3, I saw this on the FCC website with my own eyes  ...

Interesting solution.
2016-4-15
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