Servo Jitter

[Yak52Driver]

I have a Turnigy 9X with an Extreme Board running ERSKY9X V218. The problem is servo jitter, particularly on Ch 1 and Ch 2, and it doesn't matter whether I run an ACCST TX Module with a 9X8 Rx or the XJT module with X8R RXs, both TX/RX combinations experience the same issue. I have read that this may be a firmware issue but am seriously out of my depth in trying to understand this; all I know is if I plug channel 1 & 2 in I get a lot of jitter and if I look at one of the screens that is available on the TX you can see some numbers moving around. Any ideas?

[jhsa]

Turn On your radio while holding the left horizontal trim to the left for about a second, and then release it. Like this you enable the hardware menu that otherwise is disabled for safety.
Now go to "Radio Setup / Hardware". The first option is "Filter ADC". Please change the setting to "OSMP".
See if it got better..
I think this setting should be the default, at least on the 9xtreme board anyway.

João

[Yak52Driver]

Thanks, I have just tried this and it doesn't appear to make any difference. It has reduced the amount of jitter in the display numbers, but not the servos per se. The jitter is highly intermittent, it will remain silent for some seconds, then return with varying degrees, sometimes in one channel, sometimes in several.

I tried plugging the XJT module into a second Turnigy 9X I have that uses an older SmartieParts board as opposed to the Extreme, and the problem is identical, this would lead to think I am chasing something in the XJT module if it were not that the same problem is there with the basic ACCST module and its matching RX in either radio.

[jhsa]

I remember that some servos did have jitter. What servos are you using?
Did you try other servos?

João

[Yak52Driver]

I have only noticed this when I set up my 2 latest models, a R2F Yak-130 (made by Freewing) and a Freewing Mig-21. The only other thing that has changed is we have a new high power WiFi router and I am wondering whether it is some form of interference. I have to head off to a meeting now, but when I return this afternoon (I am in Australia so it is 0855) I will switch the router off and see if that makes any difference.

[Yak52Driver]

Another piece of the puzzle - if I turn on the RX without the TX there is no jitter, however, if I then turn on the TX the jitter returns, so I was thinking definitely TX, but then if I turn the TX off again so the RX goes into failsafe mode, the jitter remains! Therefore, it appears that once the RX is alive and outputting servo pulses, the jitter is there, which makes me think it is crosstalk or rf from the servo leads, does this sound possible/plausible?

[jhsa]

Which servos?

João

[Yak52Driver]

Freewing's own brand

[Yak52Driver]

I have just done a further test and it is nothing to do with my Turnigy/FrySky setup. I had never experienced this before so I assumed (always a bad thing) it was radio, however, I just plugged in one of my Hitec Optima RXs using an Eclipse Pro 7 TX and got exactly the same thing. Therefore, it appears that the very long servo leads used in both the 90mm Yak-130 and the 80mm Mig-21 are acting as antennas and picking up spurious noise. I have ordered a number of ferrite beads to use as rf chokes on the servo leads, and will also twist them to the extent I can. Hopefully the combination of these 2 things will eliminate the "jitters". At least I now know I don't have to swap out my Turnigy 9X/Extreme as I love this radio, I have upgraded the gimbals and made some other mods and it is by far the most flexible TX I have.

[jhsa]

I found strange that it would be the radio, as there aren't any other reports.
But I wouldn't be surprised as I had on my 9xtreme radio problems no one else had. And quite bad ones. Most due to the bad design of the 9x radio hardware itself. But they seemed to be solved now.

There were some reports of servo jittering in the past, but I think it was also some servo problem.. And it seems only one brand of servo did that, but I can't remember very well.. It was quite a while ago..

João