Communications Clarification

[VtKite]

Wifi - apparently there is both a 2.8 and 5.6 MHz channel. I assume the 2.8 is between the P3S, RC, and my iPhone. The 5.6 is between the P3S and RC. The 5.6 data (camera?) is passed to the iPhone over the 2.8 channel from the RC. Is this anywhere near correct?

 

[WilliamM]

Wifi - apparently there is both a 2.8 and 5.6 MHz channel. I assume the 2.8 is between the P3S, RC, and my iPhone. The 5.6 is between the P3S and RC. The 5.6 data (camera?) is passed to the iPhone over the 2.8 channel from the RC. Is this anywhere near correct?

No, on the P3S the wifi is only on 2.4 GHz. Whether between the device and the remote, and the AC and the remote, it's all at 2.4 GHz. The 5.8 GHz signal is the control signal from the remote to the AC for flight control, has nothing to do with wifi.

 

[solentlife]

OK ... first is to understand the sequence and what each does.

The RC and AC have both 2.4Ghz WiFi and 5.8Ghz Control signals.

BOTH signals relay via the RC (controller). The 2.4 is of course two way and 5.8 is one way.

The Tablet or Phone connects to the RC (controller) WiFi signal on 2.4GHz.

Think about it - there's no way any Tablet or Phone could send out strong enough signal to the AC. It has to be 'relayed' by the RC.

But it gets a little more than just that.

Lets look at what the Tablet / Phone can do ...

It can initiate Take off, RTH, Landing, camera control etc.

Some of those are COMMAND signals from RC to AC at 5.8Ghz. The Video / camera ones are 2.4Ghz.

This means that the Tablet / Phone tells RC via 2.4Ghz we want to take-off. The RC then sends that command out but as a 5.8Ghz command. Same as RTH and Landing.

Moving on - it now becomes plain that loss of 2.4Ghz does not actually affect the AC in flight as that is 5.8Ghz control matter. This is why if you lose 2.4Ghz (basically Video on your display) - you can still fly the AC ... if out of sight - then flick S2 switch to command RTH ...
This also explains why if you lose 5.8GHz control link - you cannot cancel RTH by using the Tablet / Phone ... as it sends that to RC by 2.4 which then sends out as 5.8 - but 5.8 link is not there. AC carries on with Auto RTH.

So in a nutshell .....
Display talks to RC via 2.4Ghz.
RC then has video / telemetry link to AC via 2.4Ghz and Command Control link to AC via 5.8Ghz.

Rather clever really !

Nigel

 

[VtKite]

Thanks for the info Nigel. Makes sense now. Now when we get the "Strong Interference" message which signal has the interference? I am not convinced it is real but which signal is it?

 

[RodPad]

OK ... first is to understand the sequence and what each does.

The RC and AC have both 2.4Ghz WiFi and 5.8Ghz Control signals.

BOTH signals relay via the RC (controller). The 2.4 is of course two way and 5.8 is one way.

The Tablet or Phone connects to the RC (controller) WiFi signal on 2.4GHz.

Think about it - there's no way any Tablet or Phone could send out strong enough signal to the AC. It has to be 'relayed' by the RC.

But it gets a little more than just that.

Lets look at what the Tablet / Phone can do ...

It can initiate Take off, RTH, Landing, camera control etc.

Some of those are COMMAND signals from RC to AC at 5.8Ghz. The Video / camera ones are 2.4Ghz.

This means that the Tablet / Phone tells RC via 2.4Ghz we want to take-off. The RC then sends that command out but as a 5.8Ghz command. Same as RTH and Landing.

Moving on - it now becomes plain that loss of 2.4Ghz does not actually affect the AC in flight as that is 5.8Ghz control matter. This is why if you lose 2.4Ghz (basically Video on your display) - you can still fly the AC ... if out of sight - then flick S2 switch to command RTH ...
This also explains why if you lose 5.8GHz control link - you cannot cancel RTH by using the Tablet / Phone ... as it sends that to RC by 2.4 which then sends out as 5.8 - but 5.8 link is not there. AC carries on with Auto RTH.

So in a nutshell .....
Display talks to RC via 2.4Ghz.
RC then has video / telemetry link to AC via 2.4Ghz and Command Control link to AC via 5.8Ghz.

Rather clever really !

Nigel

Hey, your getting better!

 

[RodPad]

@VtKite

I use book marks, I'm not a good typr or spellr.

I like sharing threads the I have learned from.

Lost signal (but not really)

Question about Radio, uplink, downlink, frequency, & telemetry

Rod

 

[WilliamM]

Thanks for the info Nigel. Makes sense now. Now when we get the "Strong Interference" message which signal has the interference? I am not convinced it is real but which signal is it?

I believe it's the wifi at 2.4 GHz. And agree, I'd take it with a grain of salt.

 

[VtKite]

This weekend my son in law will be here with an Android device so I can compare interference on it and my iPhone. Hoping for a DJI update to fix it but not holding my breath.

 

[solentlife]

Strong interference ... which signal ?

Primarily - I would say 2.4 ... but I have once or twice seen slightly different warning that gave indication of 5.8 interference.

One of the main points to remember is that Go or Litchi only report to you information received back through the 2.4 telemetry link to RC.

Nigel

 

[mike.alexander]

I believe Bluetooth is also 2.4GHz, so I always turn it off on whatever device (phone or tablet) I'm using for the display. That's in addition to placing all other devices I have on me (including my Apple Watch) in airplane mode to ensure there's no RF from them to interfere.

 

[solentlife]

Don't forget that both 2.4 and 5.8 are WiFi freq's ...... 5.8 is often used by commercial premises / terminals for their link to transmission towers / internals. Its often monitored as well for interference as my pal found out when flying from a car park in an industrial park ... with boosted 5.8 on his FPV !! He had a 'friendly' tap on the shoulder.

You need to pat close attention to warning message words to determine which interference.

Nigel

 

[Sprocky]

@Nigel...

Can you maybe help me please. I am losing control signal at between 50 and 150m. This has only recently started. It then goes to RTH. I still have perfect video signal. All looks fine inside the RC. Any other ideas of what I can do?

 

[solentlife]

@Nigel...

Can you maybe help me please. I am losing control signal at between 50 and 150m. This has only recently started. It then goes to RTH. I still have perfect video signal. All looks fine inside the RC. Any other ideas of what I can do?

First question is Where are you flying ? Is it open clear area or residential housing area or an industrial park or city park etc. Description of area would be good.

Do you have any obstructions between you and the aircraft ?

Do you have your antenna on the controller near vertical ? You should not have end of antenna pointing at aircraft ... it should be parallel to the legs in fact.

Make sure everything is charged up fully before the days flying.

There is not much else you can do with an out of box P3S once calibrations are done ...

Your control signal is 5.8Ghz ... and you say your video is fine. Video is on 2.4Ghz. So Magic Power and Icarus will not help there. They only boost 2.4Ghz.
We need to get your 5.8Ghz up to a level to give you range.

The simple way is Antenna ... you can replace the standard antenna with a Flat plate 14Dbi .... or other such ... but will mean opening up controller and changing that lead to fit alternative antenna.
You could fit Argtek antenna system as I have - but some people report not so good results. (I went from 300m to 2.4km ...... )
Pay a lot more and get the DBS Itelite antenna system ... which seems to have more followers ...

My first act - If I was you .... charge everything up .... drive out to really clear open area well away from 'civilisation' .... calibrate IMU and Compass .... Fly and see how far you can get before it auto RTH. Do not RTH yourself ... let it do it so you have a real figure of what distance etc.
Make a note of what warnings you get (I use a screen recorder for this DU Recorder for the Android).

If you have more than one battery - great - try another flight - but go in a different direction ... let it auto RTH again.

NOTE : When doing these flights - make your outward flight line with a steady increasing altitude as distnace increases .... I usually aim for about 100m altitude at 1000m distance HEIGHT IS IMPORTANT !

Ok so now you have a few flights logged from clear area. Once home - upload the Flight Logs to "Phantomhelp" to be able to read them and also link them to here so we can have a look ..... It may give a clue to what is happening. (CAN SOMEONE CHIP IN HERE AND GIVE THE ACTUAL WEB LINK TO UPLOAD LOGS ? ... I use Litchi and I can read direct Litchi logs).

Once we have some more detail - maybe we can suggest something ...

Finally ... believe me - I'm no guru ... I'm just like you - a guy with a Phantom !! There are many others much better than I am !! I just look at each event as logically as possible.

Nigel

 

[Sprocky]

Thanks Nigel. I always fly here, very rural area. Normally would reach at least 1km with no mods. Everything is charged, antenna positioned correctly and getting no warnings, apart from weak signal and then signal lost, then RTH. I opened the RC to check the wires. I'll post a pic.

 

[Sprocky]

Do those connections look normal.

 

[WilliamM]

View attachment 78675

Do those connections look normal.

The glue is normally on the connections, not to their side.

 

[Sprocky]

Another thing, in Healthy Drones it shows my my signal strength was good on all flights...

 

[solentlife]

Normal ? Not really.

I would pick away carefully at the glue to remove and then check that the leads are plugged in correctly. BE CAREFUL .... the plugs have a central pin that is fragile ... you must insert and press VERTICALLY ... and not just lightly ... you have to make sure it is fully home by pressing quite hard. The first 'click' is not enough ... I use a piece of wood dowel similar size with a clean square end to do the final press.

Then a dab of hot glue to fix.

Nigel