6. Radiosondes

Radiosondes are weather observation balloons used by scientists, weather agencies and military to collect data about wind, temperature, humidity, ozone and so on in the different layers of our atmosphere. If you follow the steps in this chapter of the tutorial you will be able to receive data from Radiosondes and feed it to the big map.

Prerequisites

• As for ADS-B a RTL-SDR dongle is needed. Look for a decent one with R820T or R820T2 Tuner with SMA connector and without a bandpass filter.
• One dongle can only receive one concurrent radiosonde at a time due to software limitations. If you life in an area where you expect to receive more than one at a time you can add more SDRs with the use of an antenna splitter. We have already build setups with up to 4 radiosonde SDRs with great success.
• A matching antenna is needed of course. Build or buy an antenna for 403MHz. Or use a dualband 70cm/2m Antenna with a splitter for AIS and Radiosonde. The shorter the cable from the antenna to the SDR, the better.

Hardware preparation

You need to change the id / serial number of the SDR dongle you want to use for radiosondes, to distinguish it reliably from the other rtl-sdr dongles. You do not want to mix it up after a reboot, it will result in not working radiosondes.

Plug your SDR dongle in a PC with no other RTL-SDR dongle connected. This can be your Raspberry Pi or every other Linux computer with the rtl-sdr library installed.

Set the new serial with

rtl_eeprom -s 30000001

For your first stick. If you use more than one stick for Radiosondes increase the serial +1 for each new stick like 30000002, 30000003, ... Now you can access your stick with the new serial. Beware that smaller numbers like 2 do not work.

Software installation

Make sure you have our repository enabled so you can easily install packages an receive the latest updates and improvements.

Install auto_rx

sudo apt install radiosondeautorx

Configure auto_rx

Edit /etc/default/radiosondeautorx and change at least the following parameters:

• sdr_quantity
• device_idx
• max_freq

There are lots of other options, please have a look at the official auto_rx wiki

Install radiosondefeeder

sudo apt install radiosondefeederc2is

Configure feeder

Edit /etc/default/radiosondefeederc2is to match your username and password and the logdirectory of autorx. You don't need to change the logdirectory if your're using our radiosondeautorx-package.

#Edit username an password here
username='yourusername'
password='yourpassword'

# path to your autorx log directory
path='/path_to/auto_rx/log'

Thats it!