Tagged: HAB

Creating a FSK SSDV data system for High Altitude Balloons

David and Mark are building a 115 kbit/s FSK SSDV (slow scan digital video) data system for high altitude balloons. In their system, on the balloon transmit side they use a Raspberry Pi, Raspberry Pi camera and a RFM22B wireless transceiver modulator board to transmit the SSDV FSK signal. On the receive side they use an RTL-SDR dongle, low noise preamplifier and a GNU Radio program to demodulate the SSDV images. The first video below demonstrates the hardware and GNU Radio program and shows them receiving the SSDV signal. In the second video they demonstrate that the images can be received at low signal levels (-106dBm) as well, by heavily attenuating the signal.

https://www.youtube.com/watch?v=DIWtz_GWpmo
https://www.youtube.com/watch?v=NprIhvcE7YA

If you are interested, all their code for the SSDV system has been uploaded to https://github.com/projecthorus/HorusHighSpeed.

While testing the RTL-SDR for use in this system they also measured the noise figure of an R820T RTL-SDR dongle. The noise figure at maximum gain comes out at around 5.6 dB. By adding a low noise amplifier they reduce the measured noise figure down to 2 dB.

Testing the attenuated SSDV signal reception with an RTL-SDR.
Testing the attenuated SSDV signal reception with an RTL-SDR.

HackRF Decoding PICO High Altitude Balloons (HAB)

Blogger g0hww shows us how he used his HackRF to decode Pico high altitude balloon (HAB) transmissions using gqrx and dl-fldigi. Pico balloons are small party sized high altitude balloons, typically launched by hobbyists. They have enough lift to carry a small sized ~60g payload. Since they are so small, they are usually exempt from requiring permission from the authorities, unlike full sized weather balloons.

The cheaper RTL-SDR could also be used to track these balloons.

PICO High Altitude Ballo0n Recevied with HackRF

RTL-SDR Tutorial: Receiving Weather Balloon (Radiosonde) Data with RTL-SDR

Around the world meteorological weather balloons are launched twice daily, and continuously transit weather telemetry to a ground station using something called a radiosonde. The RTL-SDR software defined radio combined with a decoding program can be used to intercept this telemetry, and display it on your own computer. You will be able to see real time graphs and data of air temperature, humidity, pressure as well as the location and height of the balloon as it makes it’s ascent.

Note that currently, this won’t work in the USA, as there are no decoding programs available for use with the telemetry protocol used in the states. The USA uses the Mark II Sippican radiosondes, while most of the rest of the world use Graw, Vaisala, Meteomodem or Meteolabor radiosondes, all of which are decodable. However, it seems that the USA is undergoing a Radiosonde Replacement System (RRS), where they are switching to Vaisala radiosondes.

This tutorial is also applicable to other software defined radios such as the Funcube dongle, Airspy, HackRF, BladeRF or even hardware radios with discriminator taps, but the RTL-SDR is the cheapest option that will work.

Examples

In this example YouTube user Superphish shows a radiosonde being received and decoded using a RTL-SDR, SDRSharp and SondeMonitor.

http://www.youtube.com/watch?v=Mz2id1cBmjs

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