RF Propogation measurements over a berm with the use of a Multicopter

The RF shielding effect of a berm was measured using a Multi-copter as part of my PhD program. LS of SA from LS telecom generously helped us with these measurements with their own Multi-copter measurement platform. The measurements were done with a transmitter located on the far side of the berm transmitting 9 vertically polarized frequencies in a horizontal direction, from 60m, directly at the berm. Below is a photo of the Multi-copter measuring in the vicinity of the berm.

Wessel, the Multi-copter pilot, landing the measurement vehicle

Wessel, the Multi-copter pilot, landing the measurement vehicle

Far side of berm, opposite side than transmitter

Far side of berm, opposite side than transmitter

Front side of berm, same side as transmitter

Front side of berm, same side as transmitter

The data was then processed and compiled together from a total of 7 10 min flights at different heights and configurations. The processed data was plotted and interpolated with python on a 2D grid with an overlay of the berm. The next 3 clips shows animations of the interpolated data over different frequencies and heights.

Final Word

I would just like to thank the measurement team and especially LS of SA for the great collaboration.

group photo

From the left:
Mathew Groch: Responsible for broadband loaded dipole antenna used in these measurements
Jan (crouching) from LS of SA
Nardus Mathyssen responsible for developing a pulse generator which will be used in future measurements
Wessel from LS of SA
Myself Hardie Pienaar
Brian from LS of SA

Crashed…

After flying in loiter mode for a while the quad copter suddenly flipped over. I immediately switched to Stabilize mode and increased throttle to try and save the situation. It stabilized itself just before hitting the ground but sadly had too much horizontal velocity when lightly snagging the grass. This caused the copter to roll and break 2 motor mounts and a landing gear. The cause of the flip was because of a bad connection to 1 of the esc’s from the APM 2.5 output.

img_2283 broken