Poor Range with 433 Mhz Radios

I have a bit of experience using Arduplane with the 3dr telemetry radios, and most of the time the radios work great. Recently, however, I have been running into a problem with poor range from my 433 Mhz modules.

I am currently using standard 3dr 433 modules and antennas with a Pixhawk autopilot. I can connect to my ground station just fine and I have a reliable signal out to about 50 meters or so. At 50 meters the signal gets very weak and by 100 meters it is entirely gone.

Things I have tried so far:
Multiple 433 modules and multiple Pixhawks.
Different Antennas
Using an APM instead of a Pixhawk
Checking the radio settings to make sure they are standard
Increased TX power to 20

I have also observed the telemetry signal in Mission Planner under the tuning window. I graphed rssi, remrssi, noise, and remnoise and watched the graph as I moved further and further from my plane. The noise levels seemed to be stable and low, under 50 units. The rssi and remrssi started out at about 230 units right next to my plane, then dropped off steadily as I moved away from the plane. Finally at about 100 meters the rssi and remrssi got as low as the noise values at about 50 units.

What I understand from this is that noise doesn’t seem to be the problem, instead it seems that I am just getting a weak signal.

Lastly, I have tried swapping the 433 radios for 915 and the 915s work great, but I need the 433 to work also.

Is anyone else experiencing these problems? Does anyone have any ideas that may help my range?


If you are using MP as your GCS, make sure that you are using the latest version 1.3.24.

What antennas are you using?