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Information for radio amateurs

This page is dedicated to the amateur radio community and lists information related to our active satellite missions. 

Want to get involved? Find information [1] on what we offer at TU Berlin, including a list of our operators and hams who we helped to obtain their license.

Active Missions

Overview of active missions
Satellite
NORAD
Frequency
MHz

Mod­u­la­tion
Baudrate
bps
Callsign
BEESAT [2]
35933
435.950
GMSK BT=0.3
4800, 9600
DP0BEE
BEESAT-2 [3]
39136
435.950
GMSK BT=0.3
4800, 9600
DP0BEF
BEESAT-3 [4]
39135
435.950
GMSK BT=0.3
4800
DP0BEG
BEESAT-4 [5]
41619
435.950
GMSK BT=0.3
4800, 9600
DP0BEH
BEESAT-5 [6]

48083
435.950
GMSK BT=0.5
1200, 2400, 4800
DP0BEI
BEESAT-6 [7]
47957
435.950
GMSK BT=0.5
1200, 2400, 4800
DP0BEJ
BEESAT-7 [8]

48084
435.950
GMSK BT=0.5
1200, 2400, 4800
DP0BEK
BEESAT-8 [9]

48085
435.950
GMSK BT=0.5
1200, 2400, 4800
DP0BEL
BEESAT-9 [10]
44412
435.950
GMSK BT=0.3
4800, 9600
DP0BEM
BEESAT-10 [11]
t.b.d.
435.950
GMSK BT=0.5
1200
DP0BEN
BEESAT-11 [12]
t.b.d.
435.950
GMSK BT=0.5
1200
DP0BEO
BEESAT-12 [13]
t.b.d.
435.950
GMSK BT=0.5
1200
DP0BEP
BEESAT-13 [14]
t.b.d.
435.950
GMSK BT=0.5
1200
DP0BEQ
TechnoSat [15]
42829
435.950
GMSK BT=0.3
4800
DP0TBA
S-Net A [16]
43188
435.950
AFSK
1200
DP0TBB
S-Net B [17]
43187
435.950
AFSK
1200
DP0TBC
S-Net C [18]
43189
435.950
AFSK
1200
DP0TBD
S-Net D [19]
43186
435.950
AFSK
1200
DP0TBE
SALSAT [20]
46495
435.950
AFSK
1200
DP0WER
TUBIN [21]
48900
435.950
GMSK BT=0.3
4800

All missions use half-duplex communications. Therefore, the above listed frequencies are valid for Up- and Downlink.

BEESATs, TechnoSat & TUBIN

Decoding Tools

A GNU Radio out of tree (OOT) module is published on GitHub [22] which can be used to demodulate raw data frames from our satellites. It demodulates the bit stream modulated with GMSK and also the Mobitex data-link layer protocol. Additionally, the Soundmodem [23] from UZ7HO supports demodulation of Mobitex frames. 

To launch the GNU Radio modules, use the flowcharts provided in the grc subfolder of the GitHub [24] repository. For BEESAT-1 use tnc_b1.grc and tnc_nx.grc for BEESAT-2,-3,-4 and -9. The flowcharts provide a TCP sever connection on port 9000 which is used to transmit demodulated messages to other programs.
The format of the messages is described in the files below.

General Information

The standard baudrate is 4800 bps but can be switched to 9600 bps for increased channel capacity at higher elevations. Each transmission at the higher baudrate is announced by a small 4800 bps header to allow for adaptive receiver re-configuration. The output power of the satellites is 27 dBm (0.5 W) for all BEESATs and 30 dBm (1 W) for TechnoSat using quarter-wave monopole antennas with toroidal radiation pattern.

On the data-link layer - as described by the OSI model - all BEESATs and TechnoSat make use of the Mobitex protocol. The modem chip used on BEESAT-1 to -4 is CML CMX909b [25]. It includes scrambling and interleaving features and forward error correction is also performed internally.

The transport layer uses individual frame headers for addressing multiple satellites and for handling variable length messages. Additionally, backward error correction adds to data consistency and transmission safety when needed. Both protocol features are realized by the attached microcontroller of the on-board and groundstation TNC.

TUBIN will be launched in 2020 and use the same telemetry format as TechnoSat. Any changes in the format will be announced prior to launch, however the modulation and coding will not change and the same TNC/ gr-tools can be used as for BEESAT and TechnoSat.

Terminal Node Controller (TNC)

Lupe [26]

Telecommand uplink and telemetry downlink always passes the terminal node controllers which are responsible for failure tolerant communication between the on-board computer and the groundstation's telemetry and telecommand server.

You may find a schematics of the TNC in the download section of this page for reference.

TUBiX10: Mission S-NET and SALSAT

The telemetry format description of TUBiX10 protocol, currently implemented in mission S-NET  [27]and SALSAT [28], can be download under "Files for Download [29]". 

Submitting Telemetry Frames

The Chair of Space Technology operates a telemetry collector server to receive raw data frames via the Simple Downlink Share Convention (SiDS) [30]. Frames can be submitted through the URL http://fachgebiet.rft.tu-berlin.de/ham/telemetry/send [31]

Helpful Links

GNU Radio Modules: github.com/kappiman/beesat-sdr [32]
Also included in gr-satellites [33] repository by EA4GPZ

Telemetry Collector Server: fachgebiet.rft.tu-berlin.de/ham/telemetry/send [34]

Telemetry Decoders by DK3WN: www.dk3wn.info/p/?page_id=75524 [35]

BEESAT-5...8 Beacon Receiver [36]

Contact

Sascha Kapitola
e-mail query [37]
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