Older articles:

  1. Reprogramming a RS41 Radiosonde for Amateur Radio Frequencies

    I decided to re-fly a Vaisala RS41 radiosonde on an upcoming SF-HAB high-altitude balloon launch. The radiosonde must be reprogrammed on amateur radio frequencies, and I decided to use the RS41ng project by Mikael Nousiainen OH3BHX. This post is a companion post to setting up a Horus Binary receiving station.

    Radiosonde Hardware

    The radiosonde I randomly pulled out of my box was V1920305, launched over a year ago from Oakland on 8 August 2023. I picked it up the next morning from a construction zone in South San Francisco, and the construction guys just gave it to me after I asked about a balloon.

    Radiosonde V1920305 flight path

    Building the firmware

    On Linux, building the RS41ng firmware is ridiculously easy. You build a local ...

    Read More →

  2. Setting Up a Linux Horus Binary Receiving Station

    The SF-HAB group is talking about doing a High-Altitude Balloon launch in the next few weeks, and asked if I had any payloads to fly. I thought it would be fun to refly all these radiosondes that I have collected.

    Looking around a projects online for reprogramming radiosondes, I came across the the great work that Mark Jessop VK5QI was doing down in Australia. Mark and David Rowe created the Horus Binary protocol, which is a low-power 100 baud 4FSK modulation scheme specifically designed for high-altitude balloons. Mikael Nousiainen OH3BHX wrote the RS41ng project which implements the Horus Binary transmitter on a regular Vaisala RS41 radiosonde.

    The next blog post will focus on reprogramming the RS41 radiosonde.

    Hardware Setup

    The ...

    Read More →

links