tiny PPM glitches cause sudden altitude drop "solved"

[teramax]

Yes, also to me, update did not solve the problem.

Here´s some Video from the glitches :
Had tried with old and new AQ Board, 6.6 r37 and 3 different recievers (gr12, gr24 old and new firmware)

My LOG ie. from the dance where no on did touch the transmitter:


What i discovered (might be a accident) hovering with gps antenna unplug there have been no glitches :
download LOG:


same day, 5 minutes later, same batterie, gps pluged in and here they are:
download LOG:

[mr_westie]

The looks like some serious drift.
Here is what mine looks like during radio idle.
I eliminated the TX by turning it off, engaging Failsafe.
You can see when the throttle channel shoots up
There is a small 1us jitter.

During this time I moved the craft around.

Just to be sure it is the converter or fc, engage your rx failsafe.

[Max]

Marcus,

You're definitely getting radio dropout issues -- check the RADIO_QUALITY graph. It's much more severe in the "with gps" log -- hard to say if that's directly GPS antenna related (somehow) or due to some other coincidence.

To state the obvious -- I would not fly like this! Except maybe under very controlled circumstances.

What would be good is if you can re-create the signal loss condition on the ground, while logging. It will be easier to come up with a solution if the situation is easily reproducible (w/out endangering your multi). See about how to monitor signal quality ("rssi") value in real-time in QGC. (also see the rest of that thread for signal quality graph examples and testing).

Can you compile your own firmware? As a quick test, you could try changing ppm.h line 34 to:
#define PPM_GUARD_PULSE_LENGTH 2700

Do you have access to an o-scope or analyzer? And that is a good question about your Rx failsafe -- what is it set to, and/or is it possible you're actually loosing radio reception? Those throttle channels dips to < 0 are strange -- I can't think of anything in the AQ code that would cause that.

-Max

[kinderkram]

Another German user solved his motor hickups by powering his FrSky receiver via separate BEC.

Powered by an ESC/BEC:



Powered by a separate BEC:



Maybe this will help others who suffer from sudden drops...

[teramax]

yes, thats good news, will try that tomorrow.
Thanks

[teramax]

finaly solved thanks to german user "rc-action_de" and "kinderkram".
Testet and i love it!
Driving the reciever with a extra BEC is a must by using Graupner Hott, look:

Without BEC: (blue line= Channel0)


with BEC: blue line=Channel0)


Greetings Marcus

[rwijnhov]

Do you use a 5v or 6v bec?

[rc-action_de]

I use 6V BEC but with 5V i have the same result.

Many regards Henry

[kinderkram]

[Max]

Sounds like good news Marcus. Still getting those little dips in radio quality though... they're small and shouldn't affect anything, but I'm not sure why you'd get those at all. Hopefully not an indication of bigger problems looming. I've seen that one other time from Frank (aka Teletubbie) using a FrSky FAAST/SBus Rx (grpahs here: viewtopic.php?f=27&t=951&start=20#p5687), and he had the AQ go into failsafe while in flight with that Rx (no problems with genuine Futaba Rx).

Were you powering anything else from the AQ besides the Rx, like servos or telemetry Tx?

-Max