The Compass-2 ground station, call sign DL0FHA, is our terrestrial radio station designed for extra planetary telecommunication with our satellite and is a constituting part of the ground segment of our satellite system. It has also the ability to communicate with other satellites and space craft in numerous digital modes but also per voice. Past missions that have been controlled by our ground station are the Compass-1 mission and the Wren mission.

We have also made several contacts with satellites like Funcube-1, Eagle-2, several AAusat satellites, C-stars, ZACUBE-1, Humsat-D and the international space station and many more.

In the Compass-2 mission, our ground station primarily receives telemetry data from our satellite ON04DL, which will be orbiting in a sun synchronous orbit at an altitude of about 630km and is therefore also a tracking station.

DL0FHA is hosted by the Faculty of Aerospace Engineering of the FH Aachen University of Applied Sciences (WGS84 coordinates: Latitude: 50.76476880; Longitude: 6.047933220) for the reception and transmission of radio signals in the 70cm ultra high frequency band (UHF) and the 2m very high frequency band (VHF). It has also an additional telecommunication port which is located at the Institute of High Frequency Technology (IHF) of the RWTH Aachen for the reception of S-Band signals using a rotor controlled parabolic dish antenna.

Also the Compass-2 mission specific high resolution data decoder/encoder with turbo-code ability is located at the IHF and receives / transmits the data per audio stream via tcp/ip to the DL0FHA ground station and future partner ground stations.

A general overview of the ground segment is described in Figure 1 using a block diagram. In this diagram also the locations for (de-)modulation, (de-)packetizing, (de-)framing and the data format, like audio, AX.25 frame, content data is indicated.

Figure 1 Block diagram of our ground segment.

Ground segment specifications

Uplink capabilities
  • VHF                yes, 100 W
  • UHF                yes, 100 W
Downlink capabilities
  • VHF                yes
  • UHF                yes
  • S-Band           yes
Antenna type(s)
  • VHF:   2 Clockwise pol. 2m 8 elements X-Yagi, 20dBD
  • VHF:   Quadrifilar Antenna; Gain: 3dBD
  • UHF:   4 Clockwise pol. 70cm 18 elements X-Yagi, 25dBD
  • UHF:   Quadrifilar Antenna; Gain: 3dBD others Diamond X-5000 Monopole 2m,  70cm & 23cm, 4.5/8.3/11.7 dBD
Rotator unit (AZ/EL)
  • Rotator controller: Nitec Satellite selector EPS 103;
  • Rotator unit: EGIS Rotor Profi Tracker CL
    • Azi. 0°-360° (480°Max)
    • Elev. 0°-70°
Radio(s) ICOM IC-910H; ICOM IC-820H; ICOM IC-821H; Yaesu FT-8800; Yaesu VR-5000; HackRf1SDR; FCD pro+
TNC(s) Martin Grüttner. TNC-7multi; UZ7HO Soft modem; AGWPE/UISS; TrueTTY CW GET; FL-Digi; 4 Amplitudes-2-OAFSK decoder and encoder with Turbo code: Developed by IHF RWTH


Ground segment computers

UTC time used Yes
Time synchronisation via NTP


Ground segment software

Satellite Control Software Dipl.-Ing. Sacha J. Tholl, Mission Control Suite
Tracking software DK1TB, Developer, SatPC32; OZ9AEC, Gpredict with Hamlib & GNURADIO; Sacha J. Tholl Mission Control Suite


Partner Ground stations and Teleports:

S-Band Teleport (only RX) DL0UA, Amateurfunkgruppe RWTH
  • Receiver: HackRF1 SDR receiver
  • UHF Antenna: Crossed Yagi
  • VHF Antenna: Crossed Yagi
  • S-Band Antenna 3m parabolic dish for downlink
  • Rotor: EGIS Rotor Profi Tracker CL
    • Azi. 0°-360° (max 480° freedom)
    • Elev. 0°-70°;
  • Controller: In-house developed by IHF RWTH
  • Tracking Software: In-house developed by IHF RWTH
Communication link to Primary GS by direct connection via tcp/ip socket.
Latitude: 50.7682° North Longitude:  6.0863° East
Partner ground station 1 Mike Rupprecht, Call sign: DK3WN
Transceiver :FT-736R (25W TX), FT-857 (50W TX)
  • WIMO WX220, 2×10 el X-Yagi, 12.3 dBD
  • MASPRO 435HS20, 2×20 el. X-Yagi, 13.4 dBD, both 360°/90° Az/El
IQ  wave file exchange by Dropbox, Decoded AX.25 data via direct link to Mission Server (PSQL)
Latitude: 49.73 °N Longitude:  8.95°E

Partner ground station 2

(if applicable)

Montaser Sallam, Call sign: JY1-SAT
  • Transceiver: ICOM IC-9100 All-in-one HF/VHF/UHF with Satellite mode, USB controlled.
  • Rotator and Controller: Yaesu G-5500 
  • Rotator PC Interface: Yaesu GS-232B
  • UHF Antenna: M2 – 436CP42UG 70cm Circularly Polarized Beams Yagi, 70 cm, 42 el., Circular Polar., Satellite, 18.9 dBD, 25 dB F/B, 1 kW
  • VHF Antenna: M2 – 2MCP22 2 Meter Circularly Polarized Beams Yagi, 2m, 22 el., Circular Polar., Satellite, 14.4 dBD, 25 dB F/B, 1.5 kW
  • VHF/UHF Pre- amps: ICOM AG-25/AG-35 144-148MHz/420-450MHz
wave file exchange by Dropbox, Decoded AX.25 data via direct link to Mission Server (PSQL)
Latitude: 31.985129° Longitude:  35.90479 °


Contact DL0FHA and DL0UA:

Ground station manager DL0FHA and Flight Director Compass-2

Dipl.-Ing. Sacha J. Tholl
S-band Teleport Manager DL0UA Dipl.-Ing. Ralf Wilke (DH3WR)