DJI Naza with hickups -- what's wrong?

[jotto]

I have a DJI Naza with TBS Discovery frame. When I fly fast forward in GPS ATTI mode, the quad sometimes get some strange hickups:

It's super stable in hover. This only happens in fast forward or sideways flight. I'm using Graupner 10" props plus standard DJI motors and ESCs.

Any theories on what's wrong?

 

[helloman1976]

I have a DJI Naza with TBS Discovery frame. When I fly fast forward in GPS ATTI mode, the quad sometimes get some strange hickups:

It's super stable in hover. This only happens in fast forward or sideways flight. I'm using Graupner 10" props plus standard DJI motors and ESCs.

Any theories on what's wrong?

I've been in the RC hobby a very, very, very long time like a lot of people on here but to me it looks like classic RC radio interference. Obviously you aren't using any servos but if you were they'd be twitching when this happens just like what you are seeing here only the signal goes through an ESC to a motor. You are close to your model yes but that doesn't mean there isn't any interference. I think I'd have to know more about your setup to tell you more. For example, before I got a filter for it, my 900mhz transmitter when set to channel 4 (1010mhz) would total prevent my 2.4Ghz radio from locking onto the receiver even from 5 feet away, if I moved closer it was fine or if I changed the channel on the transmitter to anything other that 4 and then all was good. When I put the filter in, that problem entirely went away. There are so MANY things that it could be, give me your transmitter, receiver, video rx/tx setup complete with antennas and all that and let's see if we can get to the bottom of it.

 

[jotto]

I've been in the RC hobby a very, very, very long time like a lot of people on here but to me it looks like classic RC radio interference. Obviously you aren't using any servos but if you were they'd be twitching when this happens just like what you are seeing here only the signal goes through an ESC to a motor. You are close to your model yes but that doesn't mean there isn't any interference. I think I'd have to know more about your setup to tell you more. For example, before I got a filter for it, my 900mhz transmitter when set to channel 4 (1010mhz) would total prevent my 2.4Ghz radio from locking onto the receiver even from 5 feet away, if I moved closer it was fine or if I changed the channel on the transmitter to anything other that 4 and then all was good. When I put the filter in, that problem entirely went away. There are so MANY things that it could be, give me your transmitter, receiver, video rx/tx setup complete with antennas and all that and let's see if we can get to the bottom of it.

Actually that's a plausible theory! Perhaps it's the failsafe that kicks in and makes the quad go level. Interestingly enough, it always goes to level (it tilts backwards in forward flight and leftwards in sideways right flight). I tried to reproduce it at close range after this, but then it didn't happen.

My gear is

Futaba 8FG with R6202SBW receiver with antennas flat along the front arms
ImmersionRC 600 mW 5.9 GHz video TX with skew planar antennas
Jeti Telemetry (which also uses 2.4 GHz) with antennas flat along the rear arms

 

[helloman1976]

Actually that's a plausible theory! Perhaps it's the failsafe that kicks in and makes the quad go level. Interestingly enough, it always goes to level (it tilts backwards in forward flight and leftwards in sideways right flight). I tried to reproduce it at close range after this, but then it didn't happen.

My gear is

Futaba 8FG with R6202SBW receiver with antennas flat along the front arms
ImmersionRC 600 mW 5.9 GHz video TX with skew planar antennas
Jeti Telemetry (which also uses 2.4 GHz) with antennas flat along the rear arms

Ok, I think I found your issue/s! First off you shouldn't transmit a signal on 2.4Ghz if you are using 2.4Ghz for something else, you'll get the issues you are experiencing now right all the way down to complete lockout of control. You may be on different channels but they are still too close to use together because of several reasons but I'll give you a few, proximity to radiated power, resonance frequencies etc etc etc. You also have your receiver antennas flat against the arms, don't do that. Make sure they are up, or down but in the air and open to receiving signals. Also, I have a filter on my 900mhz transmitter that blocks anything above 1300mhz completely by attenuating it. I keep my antennas straight up and down as much as possible and then I have my video antenna upside down below the multicopter so I receive 2.4Ghz from the top of the multicopter and I transmit 900mhz from the bottom of it. By doing this I get to use my Hexacopter as a Fresnel barrier, in a sense, since it has PCB board in it built into the bottom plate which is essentially a piece of metal sandwiched in there. By doing this I get a weaker transmission coming through the other side of the PCB board, where the 2.4Ghz receives signals from my radio, as the PCB board reduces exposed frequency harmonics and isolates, somewhat, my receiver from my transmitter. If receivers are near any other transmitters, move them away and this includes GPS and especially GPS . Keep them from laying on ANY wires of any kind and preferably up in the air, try that and let us know what happens. I bet it cures your problem...

 

[kloner]

the antenna placement would worry me a little, same with the telemetry.... that stuff is all considering 1000 feet being more than good enough all on

read your radio manual about range checks...... if your failsafe is setup right, the craft should be safe to walk off with and watch the blinking light on naza, should flail to rapid orange at a certain pace, if not look there

 

[jotto]

The extra telemetry is just a temporary thing, I will use a Jeti transmitter instead of the Futaba when I receive it.

I'll start with moving the antennas upwards. But the plastic arms shouldn't block the signals...?

 

[helloman1976]

The extra telemetry is just a temporary thing, I will use a Jeti transmitter instead of the Futaba when I receive it.

I'll start with moving the antennas upwards. But the plastic arms shouldn't block the signals...?

The plastic arms shouldn't block any signals you are right however screws. wires, built in PCB boards etc etc will. Keep in mind that laying the antennas flat alone in-itself might be enough regardless of what they are up against, think Vee antenna. Antennas are polarized in certain directions and will of course work in any given direction but not as intended. To get them to work as intended you have to follow the manufactures recommendations and that should tell you to have them up in the air and away from any obstacles of any kind for maximum performance. I'm not sure how much you know about electronics/electricity but when run power through a wire you create magnetic fields as well as induced voltage, both are not good for range. If your receiver wires are on the same plane and within range of those fields/current you may have range issues as a result. The best way to avoid any of these issues is to have the receiver antennas at a 90 degree plane compared to power wires and away from ANY transmitters.