Amateur radio satellite

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This article is about a series of amateur-satellites. For other uses, see Oscar (disambiguation).



OSCAR 1



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An amateur radio satellite is an artificial satellite built and used by amateur radio operators for use in the Amateur-satellite service.[1] 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 for free by licensed amateur radio operators for voice (FM, SSB) and data communications (AX.25, packet radio, APRS). Currently, over 18 fully operational amateur-satellites in orbit [2]act as repeaters, linear transponders or store and forward digital relays.


Throughout the years, amateur-satellites have helped make breakthroughs in the science of satellite communications. A few advancements 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The information presented regarding functional satellites is outdated quickly as the Amateur Radio Satellite community has become very active in building and being provided educational secondary cargo launch opportunities.  For current information please visit AMSAT for North America https://www.amsat.org/ and AMSAT-UK for Europe https://amsat-uk.org/




Contents





  • 1 History

    • 1.1 OSCAR 1


    • 1.2 OSCAR 10


    • 1.3 Other satellites



  • 2 Hardware


  • 3 Orbits


  • 4 Operations

    • 4.1 Satellite communications

      • 4.1.1 Mode designators


      • 4.1.2 Doppler shift



    • 4.2 FM LEOs



  • 5 Launches

    • 5.1 Past launches


    • 5.2 In development



  • 6 Facts

    • 6.1 Multinational effort


    • 6.2 Related names



  • 7 References


  • 8 Notes


  • 9 External links




History



OSCAR 1


Main article: OSCAR 1



First amateur radio satellite OSCAR 1, launched in 1961




Simple OSCAR beacon signal, 1962


The first amateur satellite, simply named OSCAR 1, was launched on December 12, 1961, barely four years after the launch of 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 (with Discoverer 36 as the primary) and subsequently enter a separate orbit. The satellite carried no on-board propulsion and the orbit decayed quickly. Despite being in orbit for only 22 days, OSCAR 1 was an immediate success with over 570 amateur radio operators in 28 countries forwarding observations to Project OSCAR.



OSCAR 10


Most of the components for OSCAR 10 were "off the shelf" and tested by group members. 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 on a couple of occasions to evaluate its performance and reliability. Special QSL cards were issued to those who participated in the airplane based flights. Once it was found to be operative and reliable, the satellite was shipped to Kennedy Space Center where it was mounted in the third stage of the launch vehicle.
Height: 1.35 m (53 in)
Width: 2.0 m (78.75 in)
Weight: 140 Kg (at launch), 90 Kg (after engine firings, 198 lbs).[3]



Other satellites




USSR postal stamp depicting amateur radio satellites, RS-1 and RS-2


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).



Hardware


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.



Orbits


Amateur satellites have been launched into low Earth orbits and into highly elliptical orbits.



Operations



Satellite communications


Currently amateur-satellites support many different types of operation including FM voice, SSB voice, as well as digital communications of AX.25 FSK (Packet radio) and PSK-31.



Mode designators


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...[4]






































Designator

H

A

V

U

L

S

S2

C

X

K

R
Band

15 m

10 m

2 m

70 cm

23 cm

13 cm

9 cm

5 cm

3 cm

1.2 cm

6 mm
Frequency
(General)
21 MHz
29 MHz
145 MHz
435 MHz
1.2 GHz
2.4 GHz
3.4 GHz
5 GHz
10 GHz
24 GHz
47 GHz

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.


  • Mode A: 2 m uplink / 10 m downlink

  • Mode B: 70 cm uplink / 2 m downlink

  • Mode J: 2 m uplink / 70 cm downlink


Doppler shift


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 and therefore, the receiver frequency at the ground station must be adjusted higher in order 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 in order to be received by the satellite. After the satellite passes overhead and begins to move away, this process reverses itself. 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.

















Where:
fddisplaystyle f_df_d=doppler corrected downlink frequency
fudisplaystyle f_uf_u=doppler corrected uplink frequency
fdisplaystyle ff=original frequency
vdisplaystyle vv=velocity of the satellite relative to ground station in m/s.
Positive when moving towards, negative when moving away.
cdisplaystyle cc=the speed of light in a vacuum (3×108displaystyle 3times 10^83times 10^8  m/s).






Change in frequencyDownlink CorrectionUplink Correction
Δf=f×vcdisplaystyle Delta f=ftimes frac vcDelta f=ftimes frac vcfd=f(1+vc)displaystyle f_d=f(1+frac vc)f_d=f(1+frac vc)
fu=f(1−vc)displaystyle f_u=f(1-frac vc)f_u=f(1-frac vc)

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.



FM LEOs





Yagi antenna being used to communicate through an FM LEO.


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.







































































































List of FM LEO satellites
Satellite name(s)
OSCAR
Designation

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 512AO-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)
Active
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
1269.700/1269.800/1269.900 FM
435.225 FM
N/A
Lost

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-SC5N/A
Lost
UoSAT-OSCAR 14

UO-14
145.975 FM
435.070 FM
N/A
Lost

LituanicaSAT-OSCAR 78 [5]
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
Note 1: SO-67 suffered[when?] a power board failure. The team hoped (2012) recovery to amateur radio operations was possible.[6]

Note 2: As of November 29, 2011 AO-51 has ceased all transmissions.[7]


Note 3: The ISS FM repeater is rarely activated.[8]


Note 4: New bootloader and OS for AO-27 was successfully written and installed by the team. Satellite experiences interference during uplink while above US.[9]


Note 5: The AO-16 downlink transmits in DSB-SC instead of FM, but the satellite otherwise operates like the other FM Birds.[10][11]


Note 6: EO-80 is currently[when?] completing a science mission and the FM transponder will be activated upon completion of that mission.



Launches



Past launches


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.







































































































































































































































































































































































































































































































































































In development



  • IRSHSAT-1 - A cubesat is being built by the students at Pakistan Student Satellite Program. Launch Date sometime in 2011.


  • BLUEsat - A microsatellite built by the students of The University of New South Wales. Unknown launch date. The next test will be in April 2014 when it is flown from a stratospheric weather balloon.[13]


  • ZSAT - A microsatellite initiated and funded by the U.S. Department of Science and Technology[clarification needed]. Unknown launch date.


  • AMSAT-Phase 3E - A satellite built by AMSAT. Delayed Indefinitely.[14]


  • KiwiSAT - A microsatellite built by AMSAT-ZL. Scheduled to launch from mid to late 2009.


  • ESEO - A microsatellite built by SSETI. Scheduled to launch in 2015-2016.[15]


  • AMSAT-Eagle - A satellite built by AMSAT. Cancelled.[16]


  • Delfi-n3Xt - The second nano-satellite from Delft University of Technology. Launched the 21 November 2013.[17]


  • Fox-1 - Five 1u cubesats from AMSAT-NA. Three in orbit and functioning, known as AO-85 (Fox-1A)[18], AO-91 (Fox-1B)[19], and AO-92 (Fox-1D)[20]. Fox-1Cliff (formerly Fox-1C) is awaiting launch and Fox-1E is in development.


Facts



Multinational effort




FASTRAC-A and FASTRAC-B amateur satellite, University of Texas at Austin


Currently, 23 countries have launched an OSCAR satellite. These countries, in chronological order by date of launch, include: The



  1. United States of America

  2. Australia

  3. Spain

  4. United Kingdom

  5. Japan

  6. Brazil

  7. Argentina

  8. Pakistan

  9. Russia

  10. France

  11. Portugal

  12. Korea

  13. Italy

  14. Mexico

  15. Israel

  16. Thailand

  17. South Africa

  18. Malaysia

  19. Saudi Arabia

  20. Germany

  21. India

  22. Colombia

  23. the Netherlands



Related names


SuitSat, an obsolete Russian space suit with a transmitter aboard, is officially known as OSCAR 54. In a twist of fate, "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 originally published a year after the launch of the first artificial satellite (Sputnik).



References




  1. ^ ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.57, definition: amateur-satellite service / amateur-satellite radiocommunication service


  2. ^ http://www.amsat.org/status/


  3. ^ John A. Magliacane, KD2BD. "AMSAT Spotlight". Archived from the original on 1996-10-28.CS1 maint: BOT: original-url status unknown (link) .mw-parser-output cite.citationfont-style:inherit.mw-parser-output qquotes:"""""""'""'".mw-parser-output code.cs1-codecolor:inherit;background:inherit;border:inherit;padding:inherit.mw-parser-output .cs1-lock-free abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-lock-subscription abackground:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registrationcolor:#555.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration spanborder-bottom:1px dotted;cursor:help.mw-parser-output .cs1-hidden-errordisplay:none;font-size:100%.mw-parser-output .cs1-visible-errorfont-size:100%.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-formatfont-size:95%.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-leftpadding-left:0.2em.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-rightpadding-right:0.2em


  4. ^ Standard Radar Frequency Letter-Band Nomenclature (IEEE Standard 521-1984, IEEE Std 521-2002(R2009))


  5. ^ "OSCAR Number for LituanicaSAT-1".


  6. ^
    "SA AMSAT". Southern African Amateur Radio Satellite Association. Retrieved 2012-08-09.


  7. ^ "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.


  8. ^ "ISS Fan Club". ISS Fan Club. Retrieved 2011-07-27.


  9. ^ "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


  10. ^ "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...


  11. ^ "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)


  12. ^ "VO-52 "Hamsat" end of mission". AMSAT.


  13. ^ http://www.bluesat.unsw.edu.au/


  14. ^ http://www.amsat.org/amsat-new/express/


  15. ^ http://www.esa.int/Education/ESEO_mission


  16. ^ http://www.amsat.org/amsat-new/eagle/


  17. ^ http://www.delfispace.nl/


  18. ^ "AO-85 (Fox-1A) – AMSAT-NA". www.amsat.org. Retrieved 2018-02-14.


  19. ^ "RadFxSat (Fox-1B) Launched, Designated AMSAT-OSCAR 91 (AO-91)". AMSAT-UK. 2017-11-18. Retrieved 2018-02-14.


  20. ^ "Fox-1D Launched, Designated AMSAT-OSCAR 92 – AMSAT-NA". www.amsat.org. Retrieved 2018-02-14.


  • Martin Davidoff: The Radio Amateur’s Satellite Handbook. The American Radio Relay League, Newington,
    ISBN 978-0-87259-658-0.


Notes


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  • "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.

  • "A Brief History of Amateur Satellites". N7HPR. Archived from the original on August 23, 2006. Retrieved 2006-09-05.

  • "Satellite Development Programs". The Radio Amateur Satellite Corporation. Retrieved 2006-09-05.

  • "Amateur (ham) Radio Satellites". Colorado State University. Archived from the original on 2006-08-31. Retrieved 2006-09-07.


External links





  • AMSAT Corporation - a nonprofit corporation that coordinates construction and launch of amateur radio satellites


  • Project OSCAR - club commemorating the original Project OSCAR group


  • NASA J-Track Amateur Site for tracking amateur radio satellites in real-time


  • Work-Sat - Private site with instructions for using amateur radio satellites










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