20 meters antenna

20 meters antenna

General

  • Operated by AMSAT-DL in cooperation with Bochum Observatory
  • Diameter: 20m, total weight: 220 tons
    • Elevation unit: 80 t
    • Total slewing part: 140 t
    • a 40m high air dome (radome) serves as weather protection
    • Air overpressure: 40 to 130 mm WS (automatically controlled depending on the external wind and internal air pressure conditions)
    • Weight of the shell: 3.5 t
    • Cassegrain antenna system with secondary mirror
    • Working range: 0° to 95° elevation and -360° to +360° azimuth.
    • original installed drive power: elevation 2 x 3 kW, azimuth 2 x 12 kW
    • Emergency generator (No-BREAK system): 60 kVA
    • Diameter of the radome wall: 38m
    • built 1965
  • Purpose: Basic research, space research, metereology, ionospheric research, geophysics, geodesy, space weather, deep space
  • Ground support for the Apollo missions to the moon
  • Propulsion system and RF equipment were renovated in 2003 by AMSAT-DL
  • phase-locked receivers (phase-locked) for:
    • 2.3 GHz (DSN/ham-radio)
    • 5.8 GHz (ham-radio)
    • 8.4 GHz (DSN X-Band)
    • 10.4 GHz (ham-radio X-Band)
  • Reference oscillator: 10 MHz Rb standard, HP Z3801 (GPS-locked)
  • Allan deviation approx. 1E-11(tau=100 sec)
  • complete RX chain up to baseband phase-locked (phase-locked)
  • Reception of VOYAGER 1 on March 31, 2006 at a distance of ~14.7 trillion km (~99AU).
  • Regular (24/7) reception operation of the STEREO-A/B space weather beacon since 2009 (in 2013 extended to Turbo Code by AMSAT-DL software) for NASA/NOAA including demodulation and decoding of the data, prior to forwarding the TLM frames to a central server in the USA.
  • Coherent transmitter on 2.4 GHz (magnetron, Pout = 6kW PEP, Rb locked phase)
  • S-band transmitter (amateur radio): 250W PEP
  • Planetary radar echoes on 2.45 GHz at the Venus conjunction in 2009 at a distance of 42 million kilometers
  • First discovery of ISEE-3 carrier in March 2014, primary downlink receiving station of ISEE-3 recovery operations.
  • Reception of deep space probes (incomplete):
    • 2001 Mars Odyssey
    • ACE
    • Aditya-L1
    • Akatsuki (Venus Express, Cassini) and IKAROS
    • BepiColumbo
    • CLUSTER II
    • DSCOVR
    • EMM (Hope Mars Mission)
    • Euclid
    • Europa Clipper (Jupiter)
    • ExoMars
    • Gaia
    • HAKUTO-R M1 (ispace) Moon Mission
    • HERA
    • IM-1 (Intuitive Machines) Moon Mission
    • JUICE
    • Juno
    • JWST
    • KPLO (Korean Pathfinder Lunar Orbiter)
    • Lucy
    • LunarFL
    • Mars2020
    • Mars Express
    • Mars Odyssey
    • Maven
    • MRO
    • Mars Surveyor 98
    • New Horizons
    • Parker
    • Peregrine (Astrobotic) Moon Mission
    • Psyche
    • Queqiao-2 (Chang’e 6)
    • Rosetta
    • SLIM (JAXA Moon Mission) and LEV-1
    • SOHO
    • SolarOrb
    • Stereo-A
    • Stereo-B
    • Tianwen-1
    • Ulysses
    • Venus Climate Orbiter
    • Voyager 1

Performance

  • RX: 2.2-2.45 GHz, 8.4 GHz, 10 GHz
  • TX: 2.45 GHz (license restricted)
  • complete receive path phase-locked with Rb reference and/or GPSDO:
  • Allan deviation <1E-11@100 sec

Frequency [GHz]

G/T [1/K]

3dB beamwidth [deg]

2.4

32.6 dB

0.43

8.4

41.0 dB

0.124

10.4

42.0 dB

0.10 deg (estimated)

 

  • Motor control accuracy: 10″
  • Maximum rotation speed: Azimuth 1.25 deg/s, Elevation 0.8 deg/s
  • Exact location of the Bochum antenna: N51.426990, E7.192566, 159.65m ASL (center of the elevation axis)
  • Phase center: 50mm (estimated)

Digitizer at ZF:

  • AARONIA, Spectran V6 (max. 250 MS/s)
  • bladeRF 2.0 (max. 123 MS/s, 61.44 MS/s)
  • USRP (max. 50 MS/s)
  • Airspy R2 SDR (max. 10 MS/s)
  • HPSDR (max. 384 kS/s)
  • Soundcard (48 kS/s)
  • 8.4 GHz frequency control ADC 166 kS/s
  • CCSDS standard decoder: work in progress
  • Internet connectivity: 10Mbit/s upstream, 100 Mbit/s downstream

Control Room

 

Further information:

 

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