No RC Error

[Tonyhiffman]

Hello you smart folks,
I love my H520. It is very steady, and reliable now that I finally got the software bugs worked out.
But, ever since I have had it (about 2 years now) I've gotten these error messages about the RC link lost during flight. The bird always comes back, but it its very disconcerting
It happens during a planned data planner mission, usually when it's not even 1000 feet away. Always within visual sight. I know how the antennae are supposed to be aligned and faced

Is there some way to test the signal output of the radio ? I know there is a routine o flight control, but I can't find a section to really test the radio. Any help would be appreciated.

Attached is a screen snap of the error

 

[Steve Carr]

The first thing I would suggest is removing the DataPilot app and then reinstall it.
If the problem continues then you may have to manually reinstall all of the firmware.

What versions of the firmware and DataPilot are currently installed?

 

[h-elsner]

The TLOG files on your RC contains RSSI values from the receiver in the drone. This is the only 'measurement' that can one get without very expensive RF equipment. RSSI should not be for a longer time below -85dB. Here is a chart RSSI vs. distance:


Edit: Better pictures

br HE

 

[WTFDproject]

I'm not familiar with H520, but there is a similar issue with HPlus that MAY be applicable.
This is how I THINK it works on HPlus. Others may be able to clarify.
Yuneec added "Redundant" flight control as a firmware update awhile back. The control swaps back and forth between the 2.4 and 5.8 channels. The update has to be installed on all involved components of your system. Camera, drone, and controller. If one of them is on an update version prior to redundant flight control, it appears you get a loss of signal when the others try to swap. The solution is to ensure all components in your system are on the same firmware version. Doesn't matter if the version has Redundant control, or is an earlier version, as long as all are the same.
Folks have run into the problem when swapping cameras or swapping controllers. The issue went away when everything was updated to the same version.

Again, I know almost nothing about H520, and have only a limited understanding of the issue on HPlus. But it's easy enough to check your versions, and it MIGHT help.

 

[Gadget2628]

This was an error that cropped up very early in the life of the 520. It appeared to be the direct result of an firmware upgrade.

I had it happen with both my 520's and it took a Yuneec a little while to come up with the fix. Generally the drones would do a RTH when they lost the RC . There were two instances with one drone where I would lose the RC connection but the drone continued the mission because it had the wifi link. I just had no control and my finger hovered near the kill-switch for some time. Fortunately the bird finished the mission and landed without incident. It didn't fly for a while again until the firmware was fixed.

If you haven't done any firmware updates in the last 12 months I would suggest you do the latest ones for both the airframe and controller and see if that fixes the problem.

If your firmware is up to date I would roll back the firmware on the systems to the earliest version you can get and then do a firmware update with the latest version that should hopefully fix the issue.

The roll-back of the firmware gave me control of my drones again and then I did the update with the latest firmware at that time (2019). There have been no more instances of a fully autonomous drone.

@Hayden or Yuneec Skins should be able to point you at the right firmware.

Hope this helps.

 

[Tonyhiffman]

Thank you all. I just installed the latest update, but it didn't completely take to all devices. I was getting the "cannot install x file" or something similar message. I will try to get the firmwares completely updated and to the same version. I am nervous about it because I had an inflight failure this summer about 2000 feet away, and it fell out of the sky at 400 feet. John at Yuneec skins did the repairs fairly quickly. But I never did figure out what caused it.
It is an issue that I've had since I bought it in 2018
When it does happen, it continues to fly on the programmed path, and returns home as programmed.
I'll keep you updated

 

[Tonyhiffman]

So the software is all in sync and updated
Camera FW 1.0.61A
FC 1.6.18
Gimbal 2.403
The tlog shows the average RSSI is 73% (through the UAV toolbox)
Does this seem normal? It's not showing a db output

 

[h-elsner]

Sorry, I forgot the H520 delivers % instead of dB like Typhoon H or H Plus. It's not clear what 100% is related to but 65% min is very good. No drops or gaps in the chart. That looks good. How far did you gone at this flight?

br HE

 

[Tonyhiffman]

No more than 1000 feet . Bird was 350 ag, always in line of sight..
I'm guessing other folks don't have this problem? I've also used the DBS Itelite range extender. No change

 

[h-elsner]

You are saying that you have had lost of RC connections in the flight above, the one with the very good RSSI?
Then it must be a pure SW problem with high probability on drone side.
Can you please check number of dropped packages and the drop rate of all connections? This information are in the MAV message SYS status. I hope it is somewhere in the ulog file (surely in the TLOG) and will be showed up in the PX4 log analysis.

br HE

 

[terrence davidson]

was the h520 nose facing you or was the h520 nose at 9 o clock. was the camera facing forward or was the camera facing you. I did a test flight 11-7-2020 flying the h520 with the camera at 12 ,3,6,and 9 o clock positions with the aircraft tail facing me. with the camera facing the same way as the h520 I had no rtl's triggered. however with the camera panned to 3,6 and 9 o clock at multiple distances at 380ft agl rtl's were triggering rapidly. with the h520 nose at 9 o clock facing south and flying east west at 380ft agl rtl were triggering rapidly at distance 300ft to 1000ft from controller. flying h520 with nose pointing at my location also triggered rtl's at 380 ft agl 1200 ft to 70 ft from controller rapidly. h520 nose pointing north flying east west was able to fly a bit longer but rtl's still triggered about 1250ft to 800ft from controller at 380ft agl.

 

[Tonyhiffman]

When I'm flying the H520 the camera is always pointing down at nadir position since I use it for mapping. I haven't really observed if the nose is pointing away or not. Next time I fly it I will take note.
It's heartening to know that I'm not the only person encountering this problem.
I've reviewed the signal through all the mavlink analyzers I can find and have not been able to find anything out of the ordinary in the signal. There is one test routine for tx and rx the "Flightcontrol" app on the ST16 for radio strength, but I can't find any documentation on the routine or how to use it. If anybody has any advice on that function I would like to hear it