Building a FossaSat-1 LoRa IoT Ground Station

FossaSat-1 is a recently launched open source "picosatellite" with an onboard LoRa repeater designed for Internet of Things (IoT) communications. It was launched via the Electron Rocket in New Zealand on December 6. At only 5 x 5 x 5cm in size and 250g in weight, a picosatellite is a tiny satellite that fits in your hand and can be affordably built and launched for around US$40k. 

Since the launch, it has been confirmed that FossaSat-1 was successfully launched, and is working correctly. However, the antennas have not properly deployed yet resulting in a weak signal that cannot be received by small ground stations. The team are currently working on getting the antenna manually deployed from earth and the latest updates can be found on their Twitter @FossaSys. They note that if the antennas cannot be deployed, then there is still the future launches of FossaSat-1B and FossaSat-2 to look forward to.

While waiting for the antennas to deploy you can watch Andreas Speiss' YouTube video where he explains the satellite in more detail, and shows how to build a FossaSat-1 ground station that can receive the FossaSat-1 LoRa transmission and upload it to the internet. While not SDR-related as it uses a hardware based LoRa chip, this is still an interesting project that some readers may be interested in.

#302 We build a 20 Dollars LoRa Satellite Ground Station and we follow the FossaSat-1 launch


  1. ian

    What kind of antenna is best for receiving the fossasat signal? The satellite looks in the picture as though it is using linear polarization – which would be sub-optimal for a number of reasons, not least that half the energy is being radiated in a useless direction into space. Would a circular pol antenna like a quad helix work – taking the 3 db hit, but not worrying about orientation, but avoiding the horizon and being roughly hemispherical?

    • Truth

      I just noticed that I mixed up the bitrates between the SF10 and SF11, so I plugged all the information that I could from the above link into a LoRa calculator (for an 8 byte payload, and I assumed that the checksum is used) and it gives the following slightly higher rates::
      SF10,BW=125kHz,CR=4 => Equivalent Bitrate of 1220.7 bps
      SF11,BW=125kHz,CR=4 => Equivalent Bitrate of 671.39 bps
      ( ref: )

      • Seasalt

        1220.7 bps
        SF11,BW=125kHz,CR=4 => Equivalent Bitrate of 671.39 bps

        These rates if I can equate to characters per second will be approx 80 characters per second.

        This Lora service then will be somewhere near the APRS data rate of 1200 BPS.

        Outernet on L-Band was I think 300 Baud (24 hours a day).

        For very short messages this data rate will work well. Especially as a duplex messaging service.

        I am very much looking forward to them sending up their next two satellites.

  2. Seasalt

    This is a Very interesting mini satellite project.
    Can LORA be decoded with a RTL-SDR?
    If so a amatuer radio operator could request some information in a region ie Weather for boats. The weather could then be transmitted back in LORA and could be decoded by non hams using a RTL-SDR.

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