{"id":4437436,"date":"2019-01-23T21:25:39","date_gmt":"2019-01-23T20:25:39","guid":{"rendered":"https:\/\/amsat-dl.org\/?page_id=4437436"},"modified":"2025-12-04T15:40:11","modified_gmt":"2025-12-04T14:40:11","slug":"20-meter-antenna","status":"publish","type":"page","link":"https:\/\/amsat-dl.org\/en\/20-meter-antenna\/","title":{"rendered":"20 meters antenna"},"content":{"rendered":"<h2>General<\/h2>\n<ul>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">Operated by AMSAT-DL in cooperation with <a href=\"https:\/\/www.sternwarte-bochum.de\/\" target=\"_blank\" rel=\"noopener\">Bochum Observatory<\/a><\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">Diameter: 20m, total weight: 220 tons<\/span>\n<ul>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Elevation unit: 80 t<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Total slewing part: 140 t<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">a 40m high air dome (radome) serves as weather protection  <\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Air overpressure: 40 to 130 mm WS (automatically controlled depending on the external wind and internal air pressure conditions)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Weight of the shell: 3.5 t<br \/>\n<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Cassegrain antenna system with secondary mirror<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Working range: 0\u00b0 to 95\u00b0 elevation and -360\u00b0 to +360\u00b0 azimuth.<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">original installed drive power: elevation 2 x 3 kW, azimuth 2 x 12 kW<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Emergency generator (No-BREAK system): 60 kVA<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Diameter of the radome wall: 38m<\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">built 1965<\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Purpose: Basic research, space research, metereology, ionospheric research, geophysics, geodesy, space weather, deep space<\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">Ground support for the <a href=\"https:\/\/www.honeysucklecreek.net\/other_stations\/bochum\/\" target=\"_blank\" rel=\"noopener noreferrer\">Apollo missions to the moon<\/a><\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\"><span style=\"color: #000000;\">Propulsion system and RF equipment were<\/span><span style=\"color: #000000;\"> renovated in 2003 by AMSAT-DL<br \/>\n<\/span><\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">phase-locked receivers (phase-locked) for:  <\/span><\/span>\n<ul>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">2.3 GHz (DSN\/<\/span><span style=\"color: #000000;\">ham-radio<\/span><span style=\"color: #000000;\">)<\/span><\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">5.8 GHz (ham-radio)<\/span><\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">8.4 GHz (DSN X-Band)<\/span><\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">10.4 GHz (<\/span><span style=\"color: #000000;\">ham-radio<\/span><span style=\"color: #000000;\"> X-Band)<\/span><\/span><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">Reference oscillator: 10 MHz Rb standard, HP Z3801 (GPS-locked)<\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">Allan deviation approx. 1E-11(tau=100 sec)<\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">complete RX chain up to baseband phase-locked (<\/span><span style=\"color: #000000;\">phase-locked)<\/span><\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">Reception of <a href=\"https:\/\/amsat-dl.org\/projects\/voyager\/\" target=\"_blank\" rel=\"noopener noreferrer\">VOYAGER 1<\/a> on March 31, 2006 at a distance of ~14.7 trillion km (~99AU).<\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">Regular (24\/7) reception operation of the <a href=\"https:\/\/amsat-dl.org\/en\/stereo\/\" target=\"_blank\" rel=\"noopener noreferrer\">STEREO-A\/B space weather beacon<\/a> 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 <\/span><span style=\"color: #000000;\">TLM frames to a central server in the USA.<\/span><\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">Coherent transmitter on 2.4 GHz (<\/span><span style=\"color: #000000;\">magnetron, <\/span><span style=\"color: #000000;\">Pout = <\/span><span style=\"color: #000000;\">6<\/span><span style=\"color: #000000;\">kW <\/span><span style=\"color: #000000;\">PEP,<\/span><span style=\"color: #000000;\"> Rb locked phase)<\/span><\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">S-band transmitter (amateur radio): 250W PEP<\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><a href=\"https:\/\/amsat-dl.org\/venus-echos\" target=\"_blank\" rel=\"noopener noreferrer\">Planetary radar echoes<\/a> on 2.45 GHz at the Venus conjunction in 2009 at a distance of 42 million kilometers<\/span><\/li>\n<li><span style=\"color: #000000; font-size: 12pt; font-family: arial, helvetica, sans-serif;\">First discovery of ISEE-3 carrier in March 2014, primary downlink receiving station of <a href=\"https:\/\/amsat-dl.org\/projects\/ice-isee-3\/\" target=\"_blank\" rel=\"noopener noreferrer\">ISEE-3 recovery operations<\/a>.<\/span><\/li>\n<li><span style=\"font-size: 12pt; font-family: arial, helvetica, sans-serif;\"><span style=\"color: #000000;\">Reception of deep space probes (incomplete):<\/span><\/span>\n<ul>\n<li>2001 Mars Odyssey<\/li>\n<li>ACE<\/li>\n<li>Aditya-L1<\/li>\n<li>Akatsuki (Venus Express, Cassini) and IKAROS<\/li>\n<li>Artemis I<\/li>\n<li>BepiColumbo<\/li>\n<li>Blue Ghost Mission 1 (BGM1, Firefly)<\/li>\n<li>Carruthers (CGO)<\/li>\n<li>Chang&#8217;e-3<\/li>\n<li>CLUSTER II (Salsa, Samba, Tango)<\/li>\n<li>DSCOVR<\/li>\n<li>ESCAPADE-GOLD and ESCAPADE-BLUE<\/li>\n<li>EMM (Hope Mars Mission)<\/li>\n<li>Euclid<\/li>\n<li>Europa Clipper (Jupiter)<\/li>\n<li>ExoMars<\/li>\n<li>Gaia<\/li>\n<li>GEO-1(Chimera, Epic Aerospace)<\/li>\n<li>HAKUTO-R M1 (ispace) Moon Mission<\/li>\n<li>HAKUTO-R M2 (ispace) Resilience lander<\/li>\n<li>HERA<\/li>\n<li>IMAP<\/li>\n<li>IM-1 (Intuitive Machines) Moon Mission<\/li>\n<li>IM-2 Athena (Intuitive Machines)<\/li>\n<li>JUICE<\/li>\n<li>Juno<\/li>\n<li>JWST<\/li>\n<li>KPLO (Korean Pathfinder Lunar Orbiter, Danuri)<\/li>\n<li>Lucy<\/li>\n<li>LunarFL<\/li>\n<li>LRO<\/li>\n<li>Mars2020<\/li>\n<li>Mars Express<\/li>\n<li>Mars Odyssey<\/li>\n<li>Maven<\/li>\n<li>MRO<\/li>\n<li>Mars Surveyor 98<\/li>\n<li>New Horizons<\/li>\n<li>ODIN (Astroforge)<\/li>\n<li>Parker<\/li>\n<li>Peregrine (Astrobotic) Moon Mission<\/li>\n<li>Psyche<\/li>\n<li>Queqiao-2 (Chang&#8217;e 6)<\/li>\n<li>Rosetta<\/li>\n<li>SLIM (JAXA Moon Mission) and LEV-1<\/li>\n<li>SOHO<\/li>\n<li>SolarOrb<\/li>\n<li>Stereo-A and Stereo-B<\/li>\n<li>SWFO-L1<\/li>\n<li>Tianwen-1<\/li>\n<li>Ulysses<\/li>\n<li>Venus Climate Orbiter<\/li>\n<li>Voyager 1<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2>Performance<\/h2>\n<ul>\n<li><span style=\"font-family: arial, helvetica, sans-serif;\">RX: 2.2-2.45 GHz, 8.4 GHz, 10 GHz<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif;\">TX: 2.45 GHz (license restricted)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif;\">complete receive path phase-locked with Rb reference and\/or GPSDO:<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif;\">  Allan deviation &lt;1E-11@100 sec<\/span><\/li>\n<\/ul>\n<table style=\"width: 100%; border-style: solid; border-color: #000000; height: 255px;\" width=\"100%\" cellspacing=\"0\" cellpadding=\"4\">\n<colgroup>\n<col width=\"85*\">\n<col width=\"85*\">\n<col width=\"85*\"> <\/colgroup>\n<thead>\n<tr style=\"height: 51px;\" valign=\"top\">\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">Frequency [GHz]<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">G\/T [1\/K]<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">3dB beamwidth [deg]<\/span><\/p>\n<\/td>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"height: 51px;\">\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\">2.3<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">30 dB<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">0.43<\/span><\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 51px;\" valign=\"top\">\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">2.4<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">32.6 dB<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">0.43<\/span><\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 51px;\" valign=\"top\">\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">8.4<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">40.0 dB<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">0.124<\/span><\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 51px;\" valign=\"top\">\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">10.4<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">42.0 dB<\/span><\/p>\n<\/td>\n<td style=\"width: 33%; border-color: #000000; border-style: solid; height: 51px;\" width=\"33%\">\n<p align=\"left\"><span style=\"font-family: Arial, sans-serif;\">0.10 deg (estimated)<\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<ul>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Motor control accuracy: 10&#8243;<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Maximum rotation speed: Azimuth 1.25 deg\/s, Elevation 0.8 deg\/s<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Exact location of the Bochum antenna: N51.426990, E7.192566, 205m ASL (center of the elevation axis, relative to the surface of the WSG84 ellipsoid)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Phase center: 50mm (estimated)<\/span><\/li>\n<\/ul>\n<h3><span style=\"font-family: Arial, sans-serif;\">Digitizer at ZF:  <\/span><\/h3>\n<ul>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">AARONIA, Spectran V6 (max. 250 MS\/s)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">bladeRF 2.0 (max. 123 MS\/s, 61.44 MS\/s)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">USRP (max. 50 MS\/s)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Airspy R2 SDR (max. 10 MS\/s)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">HPSDR (max. 384 kS\/s)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Soundcard (48 kS\/s)<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">8.4 GHz frequency control ADC 166 kS\/s<br \/>\n<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">CCSDS standard decoder: work in progress<\/span><\/li>\n<li><span style=\"font-family: arial, helvetica, sans-serif; font-size: 12pt;\">Internet connectivity: 10Mbit\/s upstream, 100 Mbit\/s downstream<\/span><\/li>\n<\/ul>\n<h2><\/h2>\n<h2>Live Stream<\/h2>\n<p><a href=\"https:\/\/www.youtube.com\/amsatdl\/live\" target=\"_blank\" rel=\"noopener\">https:\/\/www.youtube.com\/amsatdl\/live<\/a><\/p>\n<h2>Control Room<\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-165025 alignnone\" src=\"https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7391.JPG\" alt=\"\" width=\"5184\" height=\"3456\" srcset=\"https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7391.JPG 5184w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7391-150x100.jpg 150w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7391-300x200.jpg 300w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7391-768x512.jpg 768w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7391-1024x683.jpg 1024w\" sizes=\"auto, (max-width: 5184px) 100vw, 5184px\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-165028 alignnone\" src=\"https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7392.JPG\" alt=\"\" width=\"5184\" height=\"3456\" srcset=\"https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7392.JPG 5184w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7392-150x100.jpg 150w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7392-300x200.jpg 300w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7392-768x512.jpg 768w, https:\/\/amsat-dl.org\/wp-content\/uploads\/2018\/09\/IMG_7392-1024x683.jpg 1024w\" sizes=\"auto, (max-width: 5184px) 100vw, 5184px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>Further information:<\/p>\n<ul>\n<li><a href=\"https:\/\/www.amsat.org\/amsat\/articles\/g3ruh\/126.html\" target=\"_blank\" rel=\"noopener\">Control Software for the Bochum Radio Telescope, James Miller G3RUH<\/a>, AMSAT-DL Journal, Vol. 31, No. 3 and No. 4, 2005 <\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>General Operated by AMSAT-DL in cooperation with Bochum Observatory Diameter: 20m, total weight: 220 tons Elevation unit: 80 t Total&hellip;<\/p>\n","protected":false},"author":4,"featured_media":4437441,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-4437436","page","type-page","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/pages\/4437436","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/comments?post=4437436"}],"version-history":[{"count":11,"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/pages\/4437436\/revisions"}],"predecessor-version":[{"id":4462061,"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/pages\/4437436\/revisions\/4462061"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/media\/4437441"}],"wp:attachment":[{"href":"https:\/\/amsat-dl.org\/en\/wp-json\/wp\/v2\/media?parent=4437436"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}