The EMDRC High Altitude initiative will be using reprogrammed RS41 radiosondes to send telemetry back to the ground.
These sondes have been flashed with the open-source RS41ng firmware and make use of the Horus Binary 4FSK mode written by David Rowe and Mark Jessop (VK5QI)
Horus Binary is a robust telemetry mode designed specifically for high-altitude balloon tracking, and allows for reliable reception at many hundreds of km range with a modest receiver setup.
Horus Binary is a robust telemetry mode designed specifically for high-altitude balloon tracking, and allows for reliable reception at many hundreds of km range with a modest receiver setup.
If you'd like to be able to decode these signals first, you will need some kind of receiver for whatever frequency the telemetry is being transmitted on. Usually this is within the 434 MHz ISM/LIPD/70cm band, but could be different. You need a receiver capable of receiving Single-Sideband, in particular the 'upper' sideband ('USB' - no, not that USB). This could be a conventional amateur radio transceiver (think IC-7000, IC-706, FT-817, the list goes on and on...), or a scanner (Icom IC-R10, Yupiteru MVT-7100, etc...).
If you don't have a UHF SSB receiver lying around another option is use an SDR dongle like the RTL-SDR along with software such as SDR-Console, SDR#, or GQRX.
The easiest way to demodate telemetry is using the Horus-GUI software. A detailed guide for setting up the Horus-GUI can be found here
There's other options including running it with a Raspberry Pi headless
https://github.com/projecthorus/horusdemodlib/wiki/1.2--Raspberry-Pi-'Headless'-RX-Guide
If you don't want to go to the trouble of setting up a Raspberry Pi from scratch the HAB team have created a ready-to-go Raspberry Pi image with all the necessary software setup and configured to decode telemetry.
All you will need to do is download the image, flash it to an SD card, put it in a Raspberry Pi.
Here is a link to download the prepared image.
https://hab.rohbot.cc/hab-pi.zip