[Wid]

I am getting oscillation while hovering in attitude mode. Maybe 2 or3  per second. Things settle down when I move the pitch or roll sticks. What do I need to adjust or check?

[TheOtherCliff]

What FC is this?

If Revo class, what is your Attitude->Settings->AttiEstAlgo?
If Revo class, are you using GPS Assist?
If these are true then you probably need to reduce the brake PID or similar (VtolPathFollowerSettings)?

[Wid]

I am having the same problem on 2 250 quads. One FC is an old Atom CC3D and the other is a old "regular" CC3D. I am not using GPS or GPS assist. I am using sbus. Part of my problem is I am inexperienced with quads and FCs so flights, experimentation and analyzing results are slow going. My comprehension of all the settings involved with LibrePilot GCS is taking awhile to get up to speed. I am learning and studying and watching lots of videos. VTx and camera arrived so will install them to help see better what is going on. Thanks for your patience and help.

[TheOtherCliff]

If you are running default PIDs the next most likely thing is that you are running a slow ESC protocol like PWM@50Hz

It should be at least PWM@490Hz or PWMSync

Top of Output page

[Wid]

YEP. Running PWM@50Hz. If I change it on the output page do I need to re-calibrate ESCs.
I have 12 amp:
https://www.banggood.com/Emax-Simonk-Series-12A-20A-25A-30A-40A-ESC-For-Quadcopter-QAV-250-p-918126.html?ID=511756
I have not flashed them.
Should I use PWM@490Hz or PWMSync?

[TheOtherCliff]

Running PWM@50Hz. If I change it on the output page do I need to re-calibrate ESCs.

It depends.

Should I use PWM@490Hz or PWMSync?

For most modern ESCs, if you calibrate your ESCs with min=1000 max=1900 (instead of min=1000 max=2000) it works well with either PWM@490Hz or PWMSync.

As I recall:
To use PWMSync, your ESCs must be calibrated with something like min=1000 max=1900
With PWM@490 you can probably get away with min=1000 max=2000, but max=1900 works fine too

That is because PWMSync is basically PWM@500 which cannot run with max=2000.  The pulse happens 500 times a second.  Max=2000 means pulse width is 2000us = 2ms = 2/1000 second = 1/500 second, so at full throttle there is no pulse "off time" to measure the pulse width against.

Easy ESC calibration:
https://librepilot.atlassian.net/wiki/spaces/LPDOC/pages/12058743/ESC+Calibration

[Wid]

That fixed it. Rock steady now! And thanks for the link to ESC calibration. I had been a bit confused about which beeps when.
Thank you very much.
Wid