Rangefinder use - SF11/C - Oscillating altitude

ArduCopter Copter 3.5
1

Hello again. Working with AC 3.5.5 - Pixhawk 1.

I’ve incorporated an SF11/C rangefinder. I would like to use it for terrain following. I have a large QuadCopter that I have tuned to V3.5.5.

This issue I am having is that it will oscillate altitude - it will rise and fall, can hear the motors slowing, then speeding up when it starts to drop. It appears that the barometer value is stable, while the rangefinder value is fluctuating (as you would expect) when the bird is oscillating up and down.

Bird works well when I disconnect the rangefinder. I have it plugged into a serial port.

I will attach my BIN file.

https://drive.google.com/open?id=1iwt-n5cRcLIKe9PMtz2c50HUh3tb1AoI

Please help.

Thank you

2

I plugged to analog port and works nice, now It´s has many flights, perhaps you can pick some usefull info here : https://diydrones.com/profiles/blogs/sf-11-laser-altimeter-an-usefull-tool-for-agriculture-purpose

3

Hi, Kestrel

I experienced the same problem.
It solved by separating SF11 from telemetry radio.

4

Can you explain further please?

Thank you.

5

Turn off the power of the telemetry radio.
If oscillation is improved, move more space the SF11 and the telemetry radio.