Blog LNDW balloon project

LNDW balloon project

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Lange Nacht der Wissenschaften (Long Night of Sciences) 2016 is coming up in less than 2 days! On occasion of this event we’re going to launch an amateur radio balloon transmitting telemetry and pictures (see also: official schedule of all our activities).

Compared to our last year’s project there are some improvements: APRS/SSDV is currently new implemented by DL4MDW and DL7AD (still in testing stage). APRS is automatically forwarded to APRS-IS via regular IGates

  • no need for special software, e.g. tracking via!call=DK0TU-11. Images are going to be published on Specs for radio amateurs:

    Call/SSID:   DK0TU-11
    Takeoff:     2016-06-11 15:30 UTC (17:30 CEST)
    Modes:       144.800 MHz APRS (1k2 AFSK) for IARU region 1
                   QRG: changes in other regions if needed
                   Data: - position
                         - telemetry
                         - picture frame
                           → every 20s, beginning with ASCII symbol "{{I"
                           → to APRS-IS as "User defined experimental, type Image"
                           → publish to <>
                 144.860 MHz pictures in VGA resolution every second (9k6 GFSK)
                   Hint: this year no 600 Baud RTTY SSDV
    RX software: *nix & Windows (see below, both still under development)
    Hashtags:    #dk0tu11 #lndw16 (for social networks)

Receiving with *nix

Dependencies (e.g. config via CPAN):

  • Data::Dumper
  • Ham::APRS::IS
  • Ham::APRS::FAP
  • LWP::UserAgent
  • DateTime
  • DateTime::Format::RFC3339
  • Digest::SHA
  • Digest::CRC

For all amateur radio balloon enthusiasts fearless of running their own SDR receiver (e.g. RTL-SDR dongle) and shell scripts there is a Perl script download here for *nix with lots of dependencies (see box). You need to pipe the output of Direwolf directly to this script via console like this:

rtl_fm -f 144.860M -o 4 -s 48000 | direwolf -c direwolf.conf-sdr -r 48000 -B 9600 - |

This script decodes the data stream an pushes received pictures to blog. Details for posting:

See also this PDF for configuration of Direwolf using 9k6. A platform independent C program for demodulation is still in development. If you are interested in the software for Pecan Balloon Trackers you can find it on GitHub.

Receiving with Windows

Also this piece of software is currently under heavy development. Download via - please check for updates occasionally.

This post is licensed under CC BY 4.0 by the author.