Telemetry transmission speed

Hi, maybe this is a stupid question, but I didn’t find an answer in this forum… Maybe I was searching for the wrong terms…:

I noticed that the rate at which data is sent wirelessly to Mission Planner differs a lot between using a USB cable and a (cheap Banggood - nothing else was on stock at that time) wireless transmission. When I connect to the Pixhawk 2.1 in Mission Planner, then it downloads all the settings from the flight controller. With a wireless link, this takes aroun 3-5 times longer than with a USB cable. The variables in the “status” tab update maybe with 1-2 Hz wirelessly, while they update with 10-50 Hz when using a USB cable. I tried increasing the “airspeed” of the telemetry modules, and also increased the baud rate to 115200. This didn’t change anything. I tried MAVlink 1 and MAVlink 2 protocols. Also, changing the telemetry rates in Mission Planner doesn’t really change anything. The link quality of the wireless link shows >95%.

Is is maybe just normal that the telemetry is at such a low rate? Or are there differences between radio modules…?

the usb baudrate is alot higher than the telem radio. typically 57600 for telem, and the baudrate on usb is actually ignored.
usb can hold around 200kb/s where as the telem radio is more like 5kb/s
ie 57600 / (8+2) = 5.76kb/s (baudrate / (bits + start and stop bit)), and its half dupex, meaning that 5.76 is shared for both the upload and download, unless the air rate is set to accommodate

Dear Michael, thanks for your reply. So that means that the speed that I am getting is totally normal I guess?

at a guess, yes. click the link status link near the connect button, and it will display stats about the receive rate you are getting.