Amateur radio satellite
An amateur radio satellite is an artificial satellite built and used by amateur radio operators. It forms part of the Amateur-satellite service. These satellites use amateur radio frequency allocations to facilitate communication between amateur radio stations.
Many amateur satellites receive an OSCAR designation, which is an acronym for Orbiting Satellite Carrying Amateur Radio. The designation is assigned by AMSAT, an organization which promotes the development and launch of amateur radio satellites. Because of the prevalence of this designation, amateur radio satellites are often referred to as OSCARs.
These satellites can be used free of charge by licensed amateur radio operators for voice (FM, SSB) and data (AX.25, packet radio, APRS) communications. Currently, over 18 fully operational amateur radio satellites are in orbit. They act as repeaters, as linear transponders, and as store and forward digital relays.
Amateur radio satellites have helped advance the science of satellite communications. Contributions include the launch of the first satellite voice transponder (OSCAR 3) and the development of highly advanced digital "store-and-forward" messaging transponder techniques.
The Amateur Radio Satellite community is very active in building satellites and in finding launch opportunities. Lists of functioning satellites need updating regularly, as new satellites are launched and older ones fail. Current information is published by AMSAT (for North America, https://www.amsat.org/) and AMSAT-UK (for Europe https://amsat-uk.org/).
The first amateur satellite, simply named OSCAR 1, was launched on December 12, 1961, barely four years after the launch of the world's first satellite, Sputnik I. The beginning of this project was very humble. The satellite had to be built in a very specific shape and weight, so it could be used in place of one of the weights necessary for balancing the payload in the rocket stage. OSCAR 1 was the first satellite to be ejected as a secondary payload (the primary payload was Discoverer 36) and to subsequently enter a separate orbit. It carried no on-board propulsion and its orbit decayed quickly. Despite orbiting for only 22 days, OSCAR 1 was an immediate success. Over 570 amateur radio operators in 28 countries forwarded observations to Project OSCAR.
Most of the components for OSCAR 10 were "off the shelf". Jan King led the project. Solar cells were bought in batches of 10 or 20 from Radio Shack, and tested for efficiency by group members. The most efficient cells were kept for the project; the rest were returned to RadioShack. Once ready, OSCAR 10 was mounted aboard a private plane, and flown a couple of times to evaluate its performance and reliability. Special QSL cards were issued to those who participated in the airplane-based tests. Once it was found to be operative and reliable, the satellite was shipped to Kennedy Space Center, where it was mounted in the launch vehicle's third stage. OSCAR 10's dimensions were: Height: 1.35 m (53 in) Width: 2.0 m (78.75 in) Weight: 140 kg at launch; 90 kg after engine firings.
Other programs besides OSCAR have included Iskra (Soviet Union) circa 1982, JAS-1 (Fuji-OSCAR 12) (Japan) in 1986, RS (Soviet Union and Russia), and CubeSats. (There is a list of major amateur satellites in Japanese Wikipedia).
Narrowband Linear transponder
2400.050 - 2400.300 MHz Uplink
10489.550 - 10489.800 MHz Downlink
Wideband digital transponder
2401.500 - 2409.500 MHz Uplink
10491.000 - 10499.000 MHz Downlink
The first amateur satellites contained telemetry beacons. Since 1965, most OSCARs carry a linear transponder for two-way communications in real time. Some satellites have a bulletin board for store-and-forward digital communications, or a digipeater for direct packet radio connections.
Uplink and downlink designations use sets of paired letters following the structure X/Y where X is the uplink band and Y is the downlink band. Occasionally, the downlink letter is rendered in lower case (i.e., X/y). With a few exceptions, the letters correspond to IEEE's standard for radar frequency letter bands...
Prior to the launch of OSCAR 40, operating modes were designated using single letters to indicate both uplink and downlink bands. While deprecated, these older mode designations are still widely used in casual conversation.
Due to the high orbital speed of the amateur satellites, the uplink and downlink frequencies will vary during the course of a satellite pass. This phenomenon is known as the Doppler effect. While the satellite is moving towards the ground station, the downlink frequency will appear to be higher than normal. Hence, the receiver frequency at the ground station must be adjusted higher to continue receiving the satellite. The satellite in turn, will be receiving the uplink signal at a higher frequency than normal so the ground station's transmitted uplink frequency must be lower to be received by the satellite. After the satellite passes overhead and begins to move away, this process is reversed. The downlink frequency will appear lower and the uplink frequency will need to be adjusted higher. The following mathematical formulas relate the Doppler shift to the velocity of the satellite.
|=||doppler corrected downlink frequency|
|=||doppler corrected uplink frequency|
|=||velocity of the satellite relative to ground station in m/s.|
Positive when moving towards, negative when moving away.
|=||the speed of light in a vacuum ( m/s).|
|Change in frequency||Downlink Correction||Uplink Correction|
Due to the complexity of finding the relative velocity of the satellite and the speed with which these corrections must be made, these calculations are normally accomplished using satellite tracking software. Many modern transceivers include a computer interface that allows for automatic doppler effect correction. Manual frequency-shift correction is possible, but it is difficult to remain precisely near the frequency. Frequency modulation is more tolerant of doppler shifts than single-sideband, and therefore FM is much easier to tune manually.
A number of low earth orbit (LEO) OSCAR satellites use frequency modulation (FM). These are also commonly referred to as "FM LEOs" or the "FM Birds". Such satellites act as FM amateur radio repeaters that can be communicated through using omni-directional antennas and commonly available amateur radio equipment. Due to the relative ease of tuning FM as compared to SSB and the decreased distance of LEO satellites from earth stations communication can be achieved even with handheld transceivers and using manual doppler correction. The orbit of these satellites however causes the available time in which to communicate to be limited to only a few minutes per pass.
|Uplink (MHz)||Downlink (MHz)||CTCSS (Hz)||Status|
|Hope Oscar 68||HO-68||145.825 FM||435.675 FM||67.0||Beacon only|
|Sumbandila Oscar 671||SO-67||145.875 FM||435.345 FM||N/A||Lost|
|AMSAT-OSCAR 512||AO-51||145.880 FM||435.150 FM||N/A||Lost|
|145.920 FM||435.300 FM||67.0|
|145.880 FM||2401.200 FM||N/A|
|1268.700 FM||435.300 FM||67.0|
|1268.700 FM||2401.200 FM||67.0|
|Saudi-OSCAR 50||SO-50||145.850 FM||436.795 FM||67.0
(74.4 to activate)
|Saudi-OSCAR 41||SO-41||145.850 FM||436.775 FM||N/A||Lost|
|SUNSAT-OSCAR 35||SO-35||145.825 FM||436.250 FM||N/A||Lost|
|436.291 FM||145.825 FM|
|1265.000 FM||436.2500 FM|
|TechSat 1b-OSCAR 32||SO-32||145.850/145.890/145.930 FM
|ISS3||ARISS||437.800 FM||145.800 FM||N/A||Active|
|AMRAD-OSCAR 274||AO-27||145.850 FM||436.795 FM||N/A||Interference over USA|
|AMSAT-OSCAR 16||AO-16||145.920 FM||437.026 DSB-SC5||N/A||Lost|
|UoSAT-OSCAR 14||UO-14||145.975 FM||435.070 FM||N/A||Lost|
|LituanicaSAT-OSCAR 78||LO-78||145.950 FM||435.1755 FM||67.0||Lost|
|European-OSCAR 806||EO-80||435.080 FM||145.840 FM||210.7||Beacon only|
|Fox-1A7||AO-85||435.170 FM||145.980 FM||67||Poor battery condition|
|LAPAN-A2/ORARI||IO-86||145.880 FM||435.880 FM||88.5||Active|
|Fox-1B||AO-91||435.250 FM||145.960 FM||67.0||Active|
|Fox-1D||AO-92||435.350/1267.359 FM||145.880 FM||67.0||Active|
|Diwata-2||PO-101||437.500 FM||145.900 FM||141.3||Active by schedule|
|LilacSat-2 (CAS-3H)||144.350 FM||437.200 FM||None||Operational, but rarely active|
|FUNcube on ESEO||1263.500 FM||145.895 FM||67.0||In commissioning|
|Note 1: SO-67 suffered a power board failure. The team hoped (2012) recovery to amateur radio operations was possible.
Note 5: The AO-16 downlink transmits in DSB-SC instead of FM, but the satellite otherwise operates like the other FM Birds.
Note 6: EO-80 is currently completing a science mission and the FM transponder will be activated upon completion of that mission.
The names of the satellites below are sorted in chronological order by launch date, ascending. The status column denotes the current operational status of the satellite. Green signifies that the satellite is currently operational, orange indicates that the satellite is partially operational or failing. Red indicates that the satellite is non operational and black indicates that the satellite has re-entered the Earth's atmosphere. The country listing denotes the country that constructed the satellite and not the launching country.
|Launches (Past & Current)|
|OSCAR (OSCAR 1)||Decayed||1961-12-12|
|OSCAR II (OSCAR 2)||Decayed||1962-06-02|
|OSCAR III (OSCAR 3, EGRS-3)||Non-Operational||1965-03-09|
|OSCAR IV (OSCAR 4)||Decayed||1965-12-21|
|Australis-OSCAR 5 (OSCAR 5, AO-5, AO-A)||Non-Operational||1970-01-23|
|AMSAT-OSCAR 6 (OSCAR 6, AO-6, AO-C, P2A)||Non-Operational||1972-10-15|
|AMSAT-OSCAR 7 (OSCAR 7, AO-7, AO-B, P2B)||Semi-Operational||1974-11-15|
|AMSAT-OSCAR 8 (OSCAR 8, AO-8, AO-D, P2D)||Non-Operational||1978-03-05|
|Radio Sputnik 1 (RadioSkaf-1, RS-1)||Non-Operational||1978-10-26|
|Radio Sputnik 2 (RadioSkaf-2, RS-2)||Non-Operational||1978-10-26|
|UoSat-OSCAR 9 (UOSAT 1, UO-9)||Decayed||1981-10-06|
|Radio Sputniks RS3 through RS8||Non-Operational||1981-12-17|
|AMSAT-OSCAR 10 (Phase 3B, AO-10, P3B)||Non-Operational||1983-06-16|
|UoSat-OSCAR 11 (UoSat-2, UO-11, UoSAT-B)||Semi-Operational||1984-03-01|
|Fuji-OSCAR 12 (JAS 1, FO-12)||Non-Operational||1986-08-12|
|Radio Sputnik 10/11 (RadioSkaf-10/11, RS-10/11, COSMOS 1861)||Non-Operational||1987-06-23|
|AMSAT-OSCAR 13 (Phase 3C, AO-13, P3C)||Decayed||1988-06-15|
|UOSAT-OSCAR 14 (UoSAT-3, UO-14 UoSAT-D)||Non-Operational||1990-01-22|
|UOSAT-OSCAR 15 (UoSAT-4, UO-15, UoSAT-E)||Non-Operational||1990-01-22|
|AMSAT-OSCAR 16 (Pacsat, AO-16, Microsat-1)||Semi-Operational||1990-01-22|
|Dove-OSCAR 17 (Dove, DO-17, Microsat-2)||Non-Operational||1990-01-22|
|Weber-OSCAR 18 (WeberSAT, WO-18, Microsat-3)||Non-Operational||1990-01-22|
|LUSAT-OSCAR 19 (LUSAT, LO-19, Microsat-4)||Non-Operational||1990-01-22|
|Fuji-OSCAR 20 (JAS 1B, FO-20, Fuji-1B)||Non-Operational||1990-02-07|
|AMSAT-OSCAR 21 (RS-14, AO-21, Informator-1)||Non-Operational||1991-01-29|
|Radio Sputnik 12/13 (RadioSkaf-12/13, RS-12/13, COSMOS 2123)||Non-Operational||1991-02-05|
|UoSat-OSCAR 22 (UOSAT 5, UO-22 UoSAT-F)||Non-Operational||1991-07-17|
|KitSAT-OSCAR 23 (KITSAT 1, KO-23, Uribyol-1)||Non-Operational||1992-08-10|
|Arsene-OSCAR 24 (Arsene, AO-24)||Non-Operational||1993-05-12|
|KitSAT-OSCAR 25 (KITSAT B, KO-25, Kitsat-2, Uribyol-2)||Non-Operational||1993-09-26|
|Italy-OSCAR 26 (ITAMSAT, IO-26)||Non-Operational||1993-09-26|
|AMRAD-OSCAR 27 (EYESAT-1, AO-27)||Non-Operational||1993-09-26|
|POSAT-OSCAR 28 (POSAT, PO-28, Posat-1)||Non-Operational||1993-09-26|
|Radio Sputnik 15 (RadioSkaf-15, RS-15, Radio-ROSTO)||Semi-Operational||1994-12-26|
|Fuji-OSCAR 29 (JAS 2, FO-29, Fuji-2)||Semi-Operational||1996-08-17|
|Mexico-OSCAR 30 (UNAMSAT-2, MO-30, Unamsat-B, Kosmos-2334)||Non-Operational||1996-09-05|
|Thai-Microsatellite-OSCAR 31 (TMSAT-1, TO-31)||Non-Operational||1998-07-10|
|Gurwin-OSCAR 32 (GO-32, Gurwin-1b, Techsat-1b)||Non-Operational||1998-07-10|
|SEDSat-OSCAR 33 (SEDSat, SO-33, SEDsat-1)||Semi-Operational||1998-10-24|
|Pansat-OSCAR 34 (PAN SAT, PO-34)||Non-Operational||1998-10-29|
|Sunsat-OSCAR 35 (SUNSAT, SO-35)||Non-Operational||1999-02-23|
|UoSat-OSCAR 36 (UOSAT 12, UO-36)||Non-Operational||1999-04-21|
|ASU-OSCAR 37 (AO-37, ASUsat-1, ASUSAT)||Non-Operational||2000-01-27|
|OPAL-OSCAR 38 (OO-38, StenSat, OPAL)||Non-Operational||2000-01-27|
|Weber-OSCAR 39 (WO-39, JAWSAT)||Non-Operational||2000-01-27|
|Saudi-OSCAR 41 (SO-41, Saudisat 1A)||Non-Operational||2000-09-26|
|Saudi-OSCAR 42 (SO-42, Saudisat 1B)||Non-Operational||2000-09-26|
|Malaysian-OSCAR 46 (MO-46, TIUNGSAT-1)||Non-Operational||2000-09-26|
|AMSAT-OSCAR 40 (AO-40, Phase 3D, P3D)||Non-Operational||2000-11-16|
|Starshine-OSCAR 43 (SO-43, Starshine 3)||Decayed||2001-09-30|
|Navy-OSCAR 44 (NO-44, PCSat)||Semi-Operational||2001-09-30|
|Navy-OSCAR 45 (NO-45, Sapphire)||Non-Operational||2001-09-30|
|BreizhSAT-OSCAR 47 (BO-47, IDEFIX CU1)||Non-Operational||2002-05-04|
|BreizhSAT-OSCAR 48 (BO-48, IDEFIX CU2)||Non-Operational||2002-05-04|
|AATiS-OSCAR 49 (AO-49, Safir-M, RUBIN 2)||Non-Operational||2002-12-20|
|Saudi-OSCAR 50 (SO-50, Saudisat-1C)||Operational||2002-12-20|
|CubeSat-OSCAR 55 (Cute-1)||Operational||2003-06-30|
|CubeSat-OSCAR 57 (CubeSat-XI-IV)||Operational||2003-06-30|
|RS-22 (Mozhayets 4)||Operational||2003-09-27|
|AMSAT-OSCAR 51 (Echo, AO-51)||Non-Operational||2004-06-28|
|VUSat-OSCAR 52 (HAMSAT, VO-52, VUSat)||Semi-Operational||2005-05-05|
|AMSAT-OSCAR 54 (AO-54, SuitSat, Radioskaf)||Decayed||2005-09-08||International|
|eXpress-OSCAR 53 (XO-53, SSETI Express)||Non-Operational||2005-10-27||European Space Agency|
|CubeSat-OSCAR 58 (CO-58, Cubesat XI-V)||Operational||2005-10-27|
|CubeSat-OSCAR 56 (CO-56, Cute-1.7)||Non-Operational||2006-02-21|
|ICE Cube 1||Non-Operational||2006-07-26|
|ICE Cube 2||Non-Operational||2006-07-26|
|HITSat-OSCAR 59 (HITSat, HO-59)||Non-Operational||2006-09-22|
|Navy-OSCAR 60 (RAFT, NO-60)||Decayed||2006-12-21|
|Navy-OSCAR 61 (ANDE, NO-61)||Decayed||2006-12-21|
|Navy-OSCAR 62 (FCAL, NO-62)||Decayed||2006-12-21|
|Pehuensat-OSCAR 63 (PEHUENSAT-1, PO-63)||Decayed||2007-10-01|
|Delfi-OSCAR 64 (Delfi-C3, DO-64)||Semi-Operational||2008-04-28|
|Cubesat-OSCAR 65 (Cute-1.7+APD II, CO-65)||Operational||2008-04-28|
|Cubesat-OSCAR 66 (SEED II, CO-66)||Operational||2008-04-28|
|Sumbandila-OSCAR 67 (SumbandilaSat, SO-67)||Non-Operational||2009-09-17|
|Hope Oscar 68 (XW-1, HO-68)||Beacon-Operational||2009-12-15|
|CubeBug-2 (LUSAT-OSCAR 74)||Operational||2013-11-21|
|BRICSat-P (OSCAR 83)||Operational||2015-05-20|
|ParkinsonSAT (OSCAR 84)||Operational||2015-05-20|
|Fox-1A (OSCAR 85)||Operational||2015-10-08|
|ÑuSat-1 (LUSEX OSCAR 87)||Operational||2016-05-30|
|Fox-1B (OSCAR 91)||Operational||2017-11-18|
|Fox-1D (OSCAR 92)||Operational||2017-01-12|
- KiwiSAT - A microsatellite built by AMSAT-ZL. Flight-ready, but no launch provider found yet.
- Fox-1 - Five 1U cubesats from AMSAT-NA. Three in orbit and functioning, known as AO-85 (Fox-1A), AO-91 (Fox-1B), and AO-92 (Fox-1D). Fox-1Cliff (formerly Fox-1C) suffered a failure and Fox-1E is in development.
Currently, 24 countries have launched an OSCAR satellite. These countries, in chronological order by date of launch, include:
SuitSat, an obsolete Russian space suit with a transmitter aboard, was officially known as "AMSAT-OSCAR 54". Coincidentally, "Oscar" was the name given to an obsolete space suit by its young owner in the book Have Space Suit—Will Travel, by Robert A. Heinlein. This book was first published a year after the launch of Sputnik 1, the world's first artificial satellite.
Amateur-satellite service (also: amateur-satellite radiocommunication service) is – according to Article 1.57 of the International Telecommunication Union's (ITU) Radio Regulations (RR) – defined as «A radiocommunication service using space stations on earth satellites for the same purposes as those of the amateur service.»
This radiocommunication service is classified in accordance with ITU Radio Regulations (article 1) as follows:
Radiocommunication service (article 1.19)
- Amateur service (article 1.56)
- Amateur-satellite service (article 1.57)
In order to improve harmonisation in spectrum utilisation, the majority of service-allocations stipulated in this document were incorporated in national Tables of Frequency Allocations and Utilisations which is within the responsibility of the appropriate national administration. The allocation might be primary, secondary, exclusive, and shared.
- primary allocation: is indicated by writing in capital letters (see example below)
- secondary allocation: is indicated by small letters (see example below)
- exclusive or shared utilization: is within the responsibility of national administrations
- Example of frequency allocation
|Allocation to services|
|Region 1||Region 2||Region 3|
|7 000–7 100 AMATEUR|
|14 000–14 250 AMATEUR|
|18 068–18 168 AMATEUR|
|21 000–21 450 AMATEUR|
|24 890–24 990 AMATEUR|
|28–29.7 MHz AMATEUR|
|5 830–5 850
||5 830–5 850|
|10.5–10.6 GHz AMATEUR|
|76–77.5 RADIO ASTRONOMY|
|136–141 RADIO ASTRONOMY|
|241–248 RADIO ASTRONOMY|
In addition to the formal allocations in the main table such as above, there is also a key ITU-R footnote RR 5.282 that provides for additional allocations:-
- 5.282 In the bands 435-438 MHz, 1 260-1 270 MHz, 2 400-2 450 MHz, 3 400-3 410 MHz (in Regions 2 and 3 only)
- and 5 650-5 670 MHz, the amateur-satellite service may operate subject to not causing harmful interference to other
- services operating in accordance with the Table (see No. 5.43). Administrations authorizing such use shall ensure that
- any harmful interference caused by emissions from a station in the amateur-satellite service is immediately eliminated
- in accordance with the provisions of No. 25.11. The use of the bands 1 260-1 270 MHz and 5 650-5 670 MHz by the
- amateur-satellite service is limited to the Earth-to-space direction.
Of these, the 435-438 MHz band is particularly popular for amateur/educational small satellites such as Cubesats.
- ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.57, definition: amateur-satellite service / amateur-satellite radiocommunication service
- John A. Magliacane, KD2BD. "AMSAT Spotlight". Archived from the original on 1996-10-28.CS1 maint: BOT: original-url status unknown (link)
- "Es'hail 2 / QO-100". AMSAT-UK. 2015-06-05. Retrieved 2019-06-22.
- Standard Radar Frequency Letter-Band Nomenclature (IEEE Standard 521-1984, IEEE Std 521-2002(R2009))
- "FM Satellite Frequency Summary".
- "OSCAR Number for LituanicaSAT-1".
- "ESEO". AMSAT-UK.
- "SA AMSAT". Southern African Amateur Radio Satellite Association. Retrieved 2012-08-09.
- "AMSAT AO-51 Control Team News". AO-51 Command Team and Operations Group. Archived from the original on 2007-10-31. Retrieved 2012-01-15.
- "ISS Fan Club". ISS Fan Club. Archived from the original on 2012-01-20. Retrieved 2011-07-27.
- "Official AO-27 HomePage". AO-27 Control Operators Association. Archived from the original on 2002-06-01. Retrieved 2013-01-06.
AO-27 Turned on today. Seems good on the bootloader
- "2010 AMSAT Field Day Competition" (PDF). The Radio Amateur Satellite Corporation. 2010. p. 1. Archived from the original (PDF) on 2010-11-30. Retrieved 2011-07-26.
...the FM voice satellites like AMSAT-OSCAR 16, AMRAD-OSCAR-27, SaudiSat-Oscar-50, or AMSAT-OSCAR-51...
- "AMSAT OSCAR 16 (PacSAT)". The Radio Amateur Satellite Corporation. Archived from the original on 2011-03-03. Retrieved 2011-07-26.
Mode FM Voice Repeater (Downlink is DSB. Operation is Intermittent)
- "AO-85 Turned Off due to Return of Eclipse Periods and Poor Battery Condition". American Radio Relay League. Retrieved 2019-02-12.
- "VO-52 "Hamsat" end of mission". AMSAT.
- "KiwiSAT, Status". Retrieved 2019-12-11.
- "AO-85 (Fox-1A) – AMSAT-NA". www.amsat.org. Retrieved 2018-02-14.
- "RadFxSat (Fox-1B) Launched, Designated AMSAT-OSCAR 91 (AO-91)". AMSAT-UK. 2017-11-18. Retrieved 2018-02-14.
- "Fox-1D Launched, Designated AMSAT-OSCAR 92 – AMSAT-NA". www.amsat.org. Retrieved 2018-02-14.
- "Fox-1Cliff/AO-95 Receiver Suffers Apparent Failure". ARRL.
- ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.57, definition: amateur-satellite service / amateur-satellite radiocommunication service
- ITU Radio Regulations, CHAPTER II – Frequencies, ARTICLE 5 Frequency allocations, Section IV – Table of Frequency Allocations
- Martin Davidoff: The Radio Amateur's Satellite Handbook. The American Radio Relay League, Newington, ISBN 978-0-87259-658-0.
- "Space Satellites from the World's Garage -- The Story of AMSAT". The Radio Amateur Satellite Corporation. Archived from the original on 2006-10-05. Retrieved 2006-09-05.
- "The Extraordinary History of Amateur Radio Satellites". Space Today Online. Retrieved 2006-09-05.
- "Satellite Development Programs". The Radio Amateur Satellite Corporation. Retrieved 2006-09-05.
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