5.8 vs 2.4 distance

[KingDad1985]

How is the 32 channel hack done and does it cause any adverse side effects?

 

[Capo]

This. People like to focus on a few dB difference in RF output or antenna gain and while every bit helps a difference in the noise floor of 10-20 dB or more (which is quite possible) is going to swamp other considerations, and until this is understood then there will continue to be confusion over range reports. Unfortunately this factor cannot be quantified without both the proper (expensive) equipment and expertise, and neither is common.

One nice thing about 5.8GHz is that even if it became very popular as a Wi-Fi frequency, it will still be much less noisy than 2.4GHz outside, as it doesn't penetrate walls well. This is also it's downfall outside as it doesn't penetrate trees well either.

 

[VVATC]

Is 2.4 available for the P4? I've looked in the settings and all I see is the option to manually select frequencies on 5.8, but 2.4 isn't even an option.

 

[smiller]

One nice thing about 5.8GHz is that even if it became very popular as a Wi-Fi frequency, it will still be much less noisy than 2.4GHz outside, as it doesn't penetrate walls well. This is also it's downfall outside as it doesn't penetrate trees well either.

Yes, poorer penetration and higher path loss are reasons why the statement '5.8 GHz is always better' isn't always going to be true. It might be, or might not depending on conditions. But the 2.4 GHz ISM band is so crowded these days that interference at long ranges can be difficult to overcome.

 

[Yarome]

How is the 32 channel hack done and does it cause any adverse side effects?

32-channel hack for a step by step (simple file replacement). No adverse side effects. Your DJI app will operate normally in "Auto" mode. It just opens up the meter to all 32-channels and allows you to manually select a single preferred channel.

 

[KingDad1985]

32-channel hack for a step by step (simple file replacement). No adverse side effects. Your DJI app will operate normally in "Auto" mode. It just opens up the meter to all 32-channels and allows you to manually selected a single preferred channel.

Thank you for that video. I don't think I'll benefit much from it as I'm getting great signal on 2.4 & 5.8 at the moment.

 

[John Locke]

I did. That flight was with the L-coms. I always use channel 21 and just leave it.

Can you please share what you found inside the P4P radio? Do both antenna's have two coax wires go to them? I know the Inspire had two antenna's inside one of the antenna shells, but it was half size for the slave RC. I perceive DJI put two full length antennas inside each antenna shell. Is that what you found?

I know another post determined that when switching from 2.4 to 5.8, both signals switched to 5.8Ghz, the control signal going up, and video signal coming down. This evidence implies DJI is using two antenna PCBs inside each antenna shell. If that's the case, an antenna modification kit would need 4 SMA connectors to exit the radio, 2 antennas for each band. Am I wrong?

 

[Jeremiah Nelson]

Can you please share what you found inside the P4P radio? Do both antenna's have two coax wires go to them? I know the Inspire had two antenna's inside one of the antenna shells, but it was half size for the slave RC. I perceive DJI put two full length antennas inside each antenna shell. Is that what you found?

I know another post determined that when switching from 2.4 to 5.8, both signals switched to 5.8Ghz, the control signal going up, and video signal coming down. This evidence implies DJI is using two antenna PCBs inside each antenna shell. If that's the case, an antenna modification kit would need 4 SMA connectors to exit the radio, 2 antennas for each band. Am I wrong?

I think a clean install kit and a 2.4/5.8 dual band Omni directionality antenna would work. I didn't notice anything different in the install of the kit vs the previous p4 and I was only interested in the 2.4 so I honestly didn't pay much attention.

 

[John Locke]

I think a clean install kit and a 2.4/5.8 dual band Omni directionality antenna would work. I didn't notice anything different in the install of the kit vs the previous p4 and I was only interested in the 2.4 so I honestly didn't pay much attention.

Well that's interesting. If there was only one coax wire going to each antenna, that implies the antenna performance is compromised, if I understand antenna technology. Maybe someone in this forum with an antenna background/knowledge can elaborate, either confirm to explain this. We know the left antenna is the control signal and the right antenna is the video receiver antenna. So if the same antennas on P4P are used for 2.4 and 5.8ghz bands, this implies DJI compromised for optimal performance for one band, or both. Am I wrong?

MaxxUAS says they are getting "DBS02 like" protos soon from Itelite for P4P, apparently different in some way to accommodate 2.4 and 5.8 bands. So I wonder how that's done.

 

[Shammyh]

Well that's interesting. If there was only one coax wire going to each antenna, that implies the antenna performance is compromised, if I understand antenna technology. Maybe someone in this forum with an antenna background/knowledge can elaborate, either confirm to explain this. We know the left antenna is the control signal and the right antenna is the video receiver antenna. So if the same antennas on P4P are used for 2.4 and 5.8ghz bands, this implies DJI compromised for optimal performance for one band, or both. Am I wrong?

MaxxUAS says they are getting "DBS02 like" protos soon from Itelite for P4P, apparently different in some way to accommodate 2.4 and 5.8 bands. So I wonder how that's done.

C1 Internal Photos - Internal Photos SZ DJI TECHNOLOGY CO., LTD

Only one connection per antenna. You can't actually see the antenna itself in those photos, but if you look up the Inspire 2 remote, I think those FCC docs do include an actual photo of the antenna pcb. Only real difference is that the Inspire remote also has a separate WiFi board for the multi-controller business and a DaVinci processor on board for video decoding acceleration.

The antenna itself is definitely UWB and specifically designed to radiate both 2.4 and 5.8 ghz radio waves in both controllers though. With modern antenna design, you can really tune stuff in interesting ways... Including for multiple bands. Just look at a teardown of a modern cell phone... Very few antennas, yet a GS7/8 or iPhone 7 supports many many different frequencies.

 

[John Locke]

C1 Internal Photos - Internal Photos SZ DJI TECHNOLOGY CO., LTD

Only one connection per antenna. You can't actually see the antenna itself in those photos, but if you look up the Inspire 2 remote, I think those FCC docs do include an actual photo of the antenna pcb. Only real difference is that the Inspire remote also has a separate WiFi board for the multi-controller business and a DaVinci processor on board for video decoding acceleration.

The antenna itself is definitely UWB and specifically designed to radiate both 2.4 and 5.8 ghz radio waves in both controllers though. With modern antenna design, you can really tune stuff in interesting ways... Including for multiple bands. Just look at a teardown of a modern cell phone... Very few antennas, yet a GS7/8 or iPhone 7 supports many many different frequencies.

Thanks for sharing that, I didn't know about UWB designs. I just did a little reading about UWB antenna designs and it appears DJI is getting very clever. And to think that all the other drone companies are still using WiFi with all that handshake protocol going on.

 

[Shammyh]

Thanks for sharing that, I didn't know about UWB designs. I just did a little reading about UWB antenna designs and it appears DJI is getting very clever. And to think that all the other drone companies are still using WiFi with all that handshake protocol going on.

Right? Lightbridge is

Thanks for sharing that, I didn't know about UWB designs. I just did a little reading about UWB antenna designs and it appears DJI is getting very clever. And to think that all the other drone companies are still using WiFi with all that handshake protocol going on.

Right? DJI are far from perfect, but Lightbridge is really class-leading for non military UAS telemetry/video.

I've heard rumors LB might be some cousin/relative of DVB-T? It's definitely OFDM in some capacity. Hardware wise, it uses an Analog Devices 2x2 RF ADC, a Cyclone V FPGA, at least 1 ARM core, and some RAM. That's the minimal config in-drone or in-controller for all Lightbridge 2+ stuff.

If you're clever, and have that FPGA driving your RF back-end, you can do some pretty flexible and fun stuff with wireless transmission. And it's OTA re-configurable as a bonus.

 

[GadgetGuy]

It's all about signal to noise ratio. In urban environments the noise floor is very high, especially on 2.4Ghz. Most companies rate their specs based on ideal environments which is basically the maximum capability. I don't think anyone can fault DJI for not meetings specs when the urban noise floor is extremely high. The transmitters are limited in power by regulation and range is limited due to S/N ratio. High gain antennas can raise this ratio, but your aim is more important when doing this. 5.8Ghz has less noise at this time and is a better option in urban environments. This is why the channel mod can help. Further you get away from the normal Wi-Fi bands the better.

The channel mod actually would hurt the performance of Auto 5.8Ghz, what makes Auto 5.8Ghz so great is the Auto channel switching, as needed, to find and use the best channel, which will vary over urban areas, especially on long distance flights. The channel mod forces the selection of a single manual channel and must be manually changed, if interference occurs. What is good at launch may not be good underway. However, a highly amplified 2.4Ghz manual channel in the hack with an antenna mod will outperform the stock Auto 5.8Ghz performance, and have better penetration if LOS cannot be maintained.

 

[GadgetGuy]

Yes sorry I mean the 32 channel hack. I've see you have good luck on 5.8 but I run the L coms on channel 21 on 2.4 The flight was also a heavy urban area with a population of about 50,000. I've never used the stock transmitter. I've got an extra set of L-coms with magnetic bases if anyone wants them.

Thank you for the clarification, but you also have a transmitter mod, too, which really helps the abysmal P4P stock 2.4Ghz performance, even with the channel hack. I have yet to try my own L-coms with magetic bases, as the stock Auto 5.8Ghz is so good with no mods at all. Are you no longer using your L-com car setup, or did you somehow end up with two setups?

 

[GadgetGuy]

Is 2.4 available for the P4? I've looked in the settings and all I see is the option to manually select frequencies on 5.8, but 2.4 isn't even an option.

I assume you mean the P4P, as the P4 has no 5.8Ghz option. You have to press on the blue 5.8 to see the option to change to 2.4 and vice versa. Then, you should be able to either select Auto, or a manual channel.

 

[GadgetGuy]

One nice thing about 5.8GHz is that even if it became very popular as a Wi-Fi frequency, it will still be much less noisy than 2.4GHz outside, as it doesn't penetrate walls well. This is also it's downfall outside as it doesn't penetrate trees well either.

This is why the 5.8Ghz power output is greater than the 2.4Ghz power output in the P4P specs, and it really makes a huge difference! Less noise and more power makes for an incredible signal to noise ratio, compared to the 2.4Ghz band, even with the channel hack. Consistent 4+ miles v. 2-3 miles at best, as long as you have clear LOS.

 

[Shammyh]

The channel mod actually would hurt the performance of Auto 5.8Ghz, what makes Auto 5.8Ghz so great is the Auto channel switching, as needed, to find and use the best channel, which will vary over urban areas, especially on long distance flights. The channel mod forces the selection of a single manual channel and must be manually changed, if interference occurs. What is good at launch may not be good underway. However, a highly amplified 2.4Ghz manual channel in the hack with an antenna mod will outperform the stock Auto 5.8Ghz performance, and have better penetration if LOS cannot be maintained.

You can still select automatic channels even if you're using the 32 channel hack... Unless I'm misinterpreting your comment.

 

[Capo]

This is why the 5.8Ghz power output is greater than the 2.4Ghz power output in the P4P specs, and it really makes a huge difference! Less noise and more power makes for an incredible signal to noise ratio, compared to the 2.4Ghz band, even with the channel hack. Consistent 4+ miles v. 2-3 miles at best, as long as you have clear LOS.

I live in a rural area and see this in my own yard. I do use many 5.8GHz devices in my house, but when I'm outside, there is not one bit of interference showing. 2.4Ghz definitely shows up, even though my house is very isolated. I use 5.8GHz all the time without range issues so far.

 

[KeithAS]

Im a new p4 pro flyer. Was wondering how You change the frequency ? The owners manual is terrible.

Thanx

Did you download the full manual from DJI? There are a lot You Tube videos with good information. Just need to weed out the so-so.

 

[smiller]

This is why the 5.8Ghz power output is greater than the 2.4Ghz power output in the P4P specs, and it really makes a huge difference!

As has been discussed before, in fact even earlier in this very thread, the 2 dBm higher RF output on 5.8 GHz helps but it is not a very significant factor, in fact additional path loss on 5.8 GHz (maybe 6-8 dB at a couple of miles) more than negates the slight power advantage. If 5.8 is superior in a given situation it is due almost exclusively to a lower noise environment.