rc_update: remove 1% deadzone for RC channels 1-8

[MaEtUgR]

Solved Problem

When I joined PX4 development I assumed this is part of a sophisticated RC calibration plan but in fact it just adds a 1% deadzone to all RC channels 1-8 and does nothing for the rest of the channels 9-18. Pretty random and not something I've seen anyone ever tweak or benefit much from.

The main problem is that if you want a deadzone or not highly depends on the use case of the input. And a deadzone of 1% only helps with very precise stick hardware.

Solution

I suggest to remove this deprecated deadzone mechanism.

The next step is to instead offer one higher-level stick deadzone setting, which also applies to joystick input, only applies in places where a deadzone is necessary/desired and can be adjusted depending on the accuracy of the stick hardware.

Changelog Entry

Remove 1% deadzone for RC channels 1-8

Test coverage

Not tested yet.

[github-actions]

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Updated: 2025-10-14T05:26:57

[sfuhrer]

Yes getting rid of some unnecessary params is always highly appreciated. I also never seen anybody touching them. The interesting dead-zones are the mode-dependent ones.
Docs that need to be updated:

• PX4-Autopilot/docs/en/flight_modes_mc/altitude.md

  Line 50 in 3a734bc

  | <a id="RCX_DZ"></a>`RCX_DZ` | RC dead zone for channel X. The value of X for throttle will depend on the value of [RC_MAP_THROTTLE](../advanced_config/parameter_reference.md#RC_MAP_THROTTLE). For example, if the throttle is channel 4 then [RC4_DZ](../advanced_config/parameter_reference.md#RC4_DZ) specifies the deadzone. |

• https://github.com/PX4/PX4-Autopilot/blob/3a734bc846f2b66bcc487afc8e1515f04eea4a75/docs/en/flight_modes_mc/position.md?plain=1#L70C10-L70C16

And we'll probably need to update QGC.

[dakejahl]

Deleted params make me happy

[MaEtUgR]

Because of the positive feedback I went through the draft again to check for any remaining reference to these parameters and found:

• The docs mentioned in rc_update: remove 1% deadzone for RC channels 1-8 #25502 (comment)
• The amov parameter dump which contains every single parameter that was in existence then
• The RC calibration check which only made sure the parameter value to be sane

It's in the separate commit for review convenience: b6d2fb4

So we should save even a bit more resources now. What's open is the check in QGC what implications it has.

[sfuhrer]

Because of the positive feedback I went through the draft again to check for any remaining reference to these parameters and found:

* The docs mentioned in [rc_update: remove 1% deadzone for RC channels 1-8 #25502 (comment)](https://github.com/PX4/PX4-Autopilot/pull/25502#issuecomment-3236893087)

* The amov parameter dump which contains every single parameter that was in existence then

* The RC calibration check which only made sure the parameter value to be sane

It's in the separate commit for review convenience: b6d2fb4

Great, thanks, looks good.

What's open is the check in QGC what implications it has.

Let's do that then now!

[github-actions]

No flaws found