P4 Power Output for Video is only .598 Watts v. .746 Watts on Original P3P

[ringolong]

Not at all. My point was about people comparing the power levels in FCC documents and thinking they know what the real world difference will be. It is far more complicated than power levels. This is not ham radio. And with SDR, DJI can and has changed power levels via firmware updates. This is a tempest in a tea cup.

Why not just let members discuss what they want to discuss without the distasteful remarks? I would not have expected your earlier remark from someone who holds the position you have here.

 

[ianwood]

Why not just let members discuss what they want to discuss without the distasteful remarks? I would not have expected your earlier remark from someone who holds the position you have here.

I fail to see what is "distasteful" about any of my remarks in this thread. I stand by my belief that people are reading far too much into information in FCC documents. I am not an RF engineer but I do know that the performance of complex systems like OFDM is driven by more than power output.

People went through this over the Inspire Pro ad nauseum and after all the debate, no one was able to provide any sort of controlled side-by-side comparison that showed any real difference. Hence it being a tempest in a tea cup.

 

[ringolong]

I fail to see what is "distasteful" about any of my remarks in this thread. I stand by my belief that people are reading far too much into information in FCC documents. I am not an RF engineer but I do know that the performance of complex systems like OFDM is driven by more than power output.

People went through this over the Inspire Pro ad nauseum and after all the debate, no one was able to provide any sort of controlled side-by-side comparison that showed any real difference. Hence it being a tempest in a tea cup.

Sure you can! I guess it is too much for me to think you would be more professional in expressing your thoughts. I am finished with this discussion since it is not helping anyone.

 

[ianwood]

You're welcome to disagree with me. I've been wrong before!

 

[GadgetGuy]

I fail to see what is "distasteful" about any of my remarks in this thread. I stand by my belief that people are reading far too much into information in FCC documents. I am not an RF engineer but I do know that the performance of complex systems like OFDM is driven by more than power output.

People went through this over the Inspire Pro ad nauseum and after all the debate, no one was able to provide any sort of controlled side-by-side comparison that showed any real difference. Hence it being a tempest in a tea cup.

I relish the discussion, and appreciate your input.
So, how do you explain my own controlled side-by-side comparisons that do show real differences? Is there something else that changed between the old motor W323 and the new motor W323A P3P versions that might explain the radical difference in video stability in the 3-5 mile range under identical conditions on both birds? I, too, am no RF engineer, but I can't think of anything else that might affect my own anecdotal results, but am open to suggestions. All I really know is that the video ranges are vastly different.

 

[ianwood]

I relish the discussion, and appreciate your input.
So, how do you explain my own controlled side-by-side comparisons that do show real differences?

I'd need to see some data. Can you pull the DAT files for those runs?

EDIT: Maybe just the log file. Checking with Bud Walker to see if RSSI is in the DAT file or other metrics for signal quality.

 

[GadgetGuy]

I'd need to see some data. Can you pull the DAT files for those runs?

EDIT: Maybe just the log file. Checking with Bud Walker to see if RSSI is in the DAT file or other metrics for signal quality.

Two of the birds are no longer available. One was returned to DJI under a warranty crash replacement, and the other returned to Best Buy and replaced. However, I can readily reproduce the results at will. The old motor birds simply have a much more stable video signal at lower elevations in the same locations 3-5 miles away than the new motor bird. Can you suggest any other changes to the aircraft, between the old motor W323 and the new motor W323A, that might explain a change in video range, other than the indisputable reduction in video power output of 18% in the FCC documents? Granted, my sample size is quite small, but there is a discernable difference acecdotally. I have yet to get the same video performance from a new motor bird. I would love to, as the flight times with the new motor bird are a full 3-5 minutes longer!

 

[John Locke]

I relish the discussion, and appreciate your input.
So, how do you explain my own controlled side-by-side comparisons that do show real differences? Is there something else that changed between the old motor W323 and the new motor W323A P3P versions that might explain the radical difference in video stability

With your side by side comparisons, did you do these tests with the same controller by binding different birds to the same controller?. If not, the difference could be the controller, something as simple as a poor quality RF cable from FPVLR.

 

[GadgetGuy]

With your side by side comparisons, did you do these tests with the same controller by binding different birds to the same controller?. If not, the difference could be the controller, something as simple as a poor quality RF cable from FPVLR.

Yes, the same FPVLR v2 modded controller.
(You think I can afford two of these $850 modded controllers? )
Anything else come to mind, relating to a difference in the two P3P versions, other than the power output changes from the bird cited in the FCC specs, that could explain the vast difference in video range?

 

[ianwood]

I think we would need to use an un-modded controller to make it of any use for others.

 

[GadgetGuy]

I think we would need to use an un-modded controller to make it of any use for others.

If the controller isn't modded, the difference will likely not be noticeable, so if that is your point, I agree with you. You will lose control at about the same distance you lose FPV. However, the power differential makes a significant difference for me, using the modded transmitter at long range, low to the ground/water, where the control range can be double or triple, and the video stability can't keep up without the most powerful aircraft video power output.

 

[dwcola]

Definitely! Auto cannot use the channel hack channels. They must be manually selected. Don't use 30. It's mine!

Awesome. I'll stick to 29 or 31. Lol.

 

[GadgetGuy]

Awesome. I'll stick to 29 or 31. Lol.

Thanks!

 

[Davphys]

Can you please explain how a firmware update can increase the transmitting levels from the RC when the FCC filing specifies it at a lower level dictated by hardware?

Not at all. My point was about people comparing the power levels in FCC documents and thinking they know what the real world difference will be. It is far more complicated than power levels. This is not ham radio. And with SDR, DJI can and has changed power levels via firmware updates. This is a tempest in a tea cup.

 

[Phantom751874]

Can you please explain how a firmware update can increase the transmitting levels from the RC when the FCC filing specifies it at a lower level dictated by hardware?

Software (firmware) can change power output. This is technically possible and done all the time for many other things. Switches do the same thing. In fact there are many 5.8ghz FPV transmitters now that have dip switches that let you set 20mw or 200mx of power output. Not sure if that's what you were asking, if it was technically possible?

 

[GadgetGuy]

Software (firmware) can change power output. This is technically possible and done all the time for many other things. Switches do the same thing. In fact there are many 5.8ghz FPV transmitters now that have dip switches that let you set 20mw or 200mx of power output. Not sure if that's what you were asking, if it was technically possible?

I'm less concerned with the P4 RC power output, for which I already have a fully compatible solution that pairs easily with the P4 aircraft (FPVLR v2 mod with 3.0A boosters on a GL300A RC) than I am with the limited video power output from the P4 aircraft, which is a full 20% less than the original W323 P3P, which was 0.746 watts. No way to remedy that without cracking open the P4 bird and installing an amp on the aircraft video power downlink, with a supporting external antenna.

 

[Phantom751874]

I'm less concerned with the P4 RC power output, for which I already have a fully compatible solution that pairs easily with the P4 aircraft (FPVLR v2 mod with 3.0A boosters on a GL300A RC) than I am with the limited video power output from the P4 aircraft, which is a full 20% less than the original W323 P3P, which was 0.746 watts. No way to remedy that without cracking open the P4 bird and installing an amp on the aircraft video power downlink, with a supporting external antenna.

Yes I know. If DJi decides they want to up power output they could through a firmware update I guess is all I am saying. Whether they would be allowed to do it without creating another revision # for the P4 is another question.

 

[GadgetGuy]

Yes I know. If DJi decides they want to up power output they could through a firmware update I guess is all I am saying. Whether they would be allowed to do it without creating another revision # for the P4 is another question.

Does this mean that we are barking up the wrong tree, and that simple jailbreaking of the firmware could increase the video power output from the aircraft? That would be exciting!

 

[N017RW]

Can you please explain how a firmware update can increase the transmitting levels from the RC when the FCC filing specifies it at a lower level dictated by hardware?

RF power adjustment is not limited to hardware nor is it dictated to be such.
Your cellphone is constantly changing its output power and don't forget the FCC/CE Tx adjustment made depending on your GPS determined location.

 

[Mad_angler1]

Ohh god here we go again