John - would the GL658A R/C pair with a P3P. KenI've been disappointed in the P4 signal integrity of the stock radio. I know people have been getting some good range with various antenna enhancements, and I generally use a surfer also (I just bought the Itelite antenna), but I'm joining the camp of Gadget Guy and wanted to express my disappointment in DJI's continued reduction in power output of Lightbridge. I'm perplexed why DJI would do this, I really don't think they exceeded RF power guidelines from the FCC for the 2.4Ghz band they're using for Lightbridge, yet the evidence shows they are gradually lowering the power of the RC. Go figure.
With my P3P (bought July 2, 2015) I never lost control signal first, I would always lose video signal first. However with P4 I often lose control signal first, sometimes triggering RTH. My flying is always LOS, no trees, away from the city, such as ocean flying, local hills, in safe areas.
Out of curiosity I bought an RF meter to read the output power of my radios. This isn't a super accurate method I admit, but it's a ballpark representation of what's going on I think. These results appear to match the FCC filings by DJI, saying they are lowering the RF output.
It appears the P4 has the weakest control signal since Phantom started using Lightbridge. This explains my experience of getting NO SIGNAL scenarios with P4, when I don't have that experience with my P3P in the same area I fly all the time. Sometimes my P4 drops control signal for a couple seconds, sometimes over 3 seconds, which triggers RTH.
When I took these measurements the numbers jumped around a little, but what I show here is pretty much the average of the numbers for each unit. I got number higher and lower for each the RCs, these photos represent an average.
It appears getting an Inspire controller for our P4 is the hot ticket. I can tell you from first hand experience that I've been amazed at the improved signal integrity with the P4 craft using an Inspire controller, the range is great in comparison to the stock P4 RC. It's interesting the P4 craft shows slightly more video output power than the P3P. That's promising, but the P4 RC control signal is what's so bad IMO. Using the Inspire RC I've gone 12,000 with no surfer and not a glitch. But using the P4 RC I'm lucky to get 5000' before I start getting NO SIGNAL notices, intermittently.
BTW, the P4 and P4 RC have the latest firmware.
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RF power measurements
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GadgetGuy
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Yes. That's what people linked with the P3P to get HDMI support before DJI released the HDMI module for $99.
But GL300C = 303mw = 24.81db ?
That wired comparison you show is irrelevant to my comparison interest, which didn't have the SMA connectors for testing. I was interested in comparing different RCs, not actual output.
My relevance tests show a 50% greater output from the GL658A versus GL300C, when linked to a P4.
Sorry for my bad english.
My question: I bought sunhans booster 2.5W for GL300C. Sunhans max input power = 20db, however GL300C has 303mw (24.81db) of power output, so I installed two 5db attenuators on each GL300C antenna ...
MaxxUAV said that gl300C = 11.6db
.. DJi specifications FCC are wrong?
My question: I bought sunhans booster 2.5W for GL300C. Sunhans max input power = 20db, however GL300C has 303mw (24.81db) of power output, so I installed two 5db attenuators on each GL300C antenna ...
MaxxUAV said that gl300C = 11.6db
.. DJi specifications FCC are wrong?
Last edited:
N017RW
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Sorry for my bad english.
My question: I bought sunhans booster 2.5W for GL300C. Sunhans max input power = 20db, however GL300C has 303mw (24.81db) of power output, so I installed two 5db attenuators on each GL300C antenna ...
MaxxUAV said that gl300C = 11.6db
Are you in the USA?
If I understand the situation correctly...
CE power output is 17dBm.
Add the 5dBm of your attenuator and you're at 16.6dBm.
A nominal measurement value given the precision of your equipment and any insertion connector/cable losses.
I'm in Brazil.
My GL300C USA >>>FCC : SS3-GL3001510 >>> Tx 303mw = 24.81db
MaxxUAV said that GL300C has 14.45mw = 11.6db
What is true: 303mw or 14.45mw?
N017RW
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Do you know what the RF limits are in Brazil?
The GL300C will not output the FCC (USA) RF power levels in all countries.
If you are limited to CE (non-USA) RF levels and you have a 5dB attenuator in-line then your measurements shown in the photo you posted is nominal (correct) as I said in post #169 above.
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N017RW
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It's not about where it's sold, it's where it is operating and that is determined by the P4s GPS receiver.
So, DJi GPS identifies the country, and firmware reduces or increases output power according to location?
N017RW
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N017RW
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GadgetGuy
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If you need or want the 5+ mile stock range of the P4P in Auto 5.8Ghz with clear LOS and just a windsurfer on FCC, the P4A will sorely disappoint. You lose the legendary 5.8Ghz band, and the stock 2.4Ghz performance is no better than its predecessors, which is horrible. By the time you add an aftermarket 2.4Ghz antenna extender and boosters to the P4A, you will have exceeded the cost of the P4P, had you bought it originally. Get the P4P and don't look back!
I have looked at the power levels measured by KyleMaxxUAV but as he is in Canada I believe he will be running the lower CE power. Is there anyone in an FCC power zone who has used a directly connected RF power meter (ANT modded RC with SMA's) to show the higher FCC power outputted from a GL300C P4S RC.
