Amateur satellites

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Regulatory considerations

For all space radiocommunication services, including the amateur satellite service, the use of a frequency assignment may cause harmful interference to a service of another administration. It is clear that the space station is required to be notified.

The satellite operated under an amateur license authorization is licensed by national administration and will have an amateur callsign. The Advanced Publication (API) to ITU will show Class of Station "EA". The amateur satellite station will operate in accordance with ITU Radio Regulations (RR) articles 1.56 , 1.57 and 25.

The use of spectrum allocated to the amateur satellite service is limited to Educational and amateur radio missions. These are satellite missions with the sole aim of educating people about space, electronics and all aspects of physics involved in space; as well as satellites used for amateur radio “self-training and communication”, with no pecuniary interest, as defined in Article 1 of the RR.

Experimental and research missions are missions with one or more of the following purposes:

  • To demonstrate a novel space technology in the space environment
  • To perform a proof-of-concept for a certain application involving one or more nanosatellites and picosatellites
  • To perform space research (primarily earth-orbiting, but also lunar and deep space applications).

In general these missions will use frequency bands allocated to the space operation, space research and Earth exploration-satellite services.

Commercial missions, i.e. delivering a certain service in certain areas of applications with a clear pecuniary interest, will operate in frequency bands allocated to that specific service. Examples include missions for Earth observation and telecommunication.

Combined missions. A combined satellite mission has an amateur payload and a payload that belongs to a different service. Both payloads use their own frequency allocations. They can use the same frequency bands for TT&C.

IARU frequency coordination

Amateur radio operators maintain an effective tradition of self-regulation, including the coordination of frequencies. Satellite frequencies in bands allocated to the amateur satellite service are coordinated by the IARU Satellite Frequency Coordination Panel. The strong preference is for all satellites using spectrum allocated to the amateur and amateur-satellite services to operate under amateur licenses and within the definition of the amateur-satellite service and the service-specific Article 25 of the Radio Regulations. The IARU believes the definition is sufficiently broad to encompass nearly all educational satellite projects that include giving students hands-on experience with radiocommunication and are conducted under an amateur license. The IARU will only coordinate a non-amateur satellite if an administration directs in writing that it be operated in an amateur-satellite band under an experimental or other non-amateur license. Satellites with combined amateur and non-amateur missions will continue to be coordinated.

Frequency Planning

In general: in accordance with ITU Radio Regulations and IARU regional bandplans. Exceptions require consultation of the IARU Regions and approval of the IARU officers.

HF bands allocated to the amateur satellite service

  • 7.000-7.100 MHz
  • 14.000-14.250 MHz
  • 18.068-18.168 MHz
  • 21.000-21.450 MHz
  • 24.890-24.990 MHz
  • 28.000-29.700 MHz

10 meter band

available for satellite use 29.300-29.510 MHz.

W2RS remembers:

  • 29.300-29.400 is for digital uplinks
  • 29.400-29.510 linear transponder
  • 29.400-29.500 for AO-7 linear transponder downlink

2 meter band

available for satellite use

  • 145.800-146.000 MHz
  • 145.200 and 145.490 MHz for manned space missions only
  • 144.000-144.025 MHz for downlink in Region 1

In Region 1, for FM voice communications with special stations like manned spacecraft it is recommended to use 145.200 MHz for simplex operation or 145.200/145.800 MHz for split-channel operation.

Common uses: 145.2 MHz, in Region 1, and 145.49 MHz in Regions 2 and 3, is used for ISS uplink. 145.800 MHz is used for ISS downlink world-wide. 145.825 is used for ISS packet operation world-wide. None of these frequencies are mentioned in the Region 3 band plan.

In Regions 1, 145.794 – 145.806 MHz is used for FM/Digital Voice space communication with 12 kHz bandwidth. 145.806 – 146.0 MHz is used only for satellite communication with 12 kHz bandwidth for all modes.

In Region 2, 144.490 MHz may be used for FM voice uplinks to the International Space Station. Priority should be given to this activity when required.

In Region 3, in the radio regulations the band 144-146 MHz is allocated to the amateur and amateur-satellite services on a primary basis. However, to keep harmonize in all Regions, the band 145.8 - 146 MHz is exclusively identified for the amateur-satellite service.

In the past the IARU Satellite Frequency Coordination Panel recommended DL on 145 MHz and UL on 435 MHz because of better link budget and less unwanted interference. However in most of Asia the practice is UL on 145 MHz. Still the panel encourages transponders to use 435-438 MHz for uplinks and 145.8-146.0 MHz for downlinks. This would reduce non-amateur interference through the transponder.

There is a risk of difficulties with commanding the spacecraft using the amateur 70cm, as many reported such issues in Europe. We understand that this is probably the result of our sharing with a number of high power systems operating in the 435-437 MHz region (like some high power early warning radars) , more specially in the North Sea and Central Europe.

For several countries coordinating of 70 cm is a problem .

We don’t coordinate experimental stations in 2 meter band

70 cm band

Available for satellite use is the frequency band 435.000-438.000 MHz. In general the maximum bandwidth is 100 kHz.
There is a general agreement that specific rules -at this stage- are not needed.

Transponders and repeaters

Current practice is that transponders downlinks go around 436. MHz and transponder uplinks right above 435 MHz.
The original idea of keeping transponder inputs low was to ensure that the third harmonic of the on-board VHF transmitter was kept as far away as possible.
We want to give special attention to protect transponder and repeater input frequencies during coordination.


It is suggested to put amateur telemetry, etc. above transponders at 435 MHz

Information related to decommissioned satellites

We lack information when a satellite is decommissioned (reentry, end-of-life, failure, etc). This information could be useful for future coordinations. Mike’s SatBlog [1] certainly gives some information and Bryan Klofas’s pages [2] covers lots of cubesats but is not 100% complete/accurate ditto this one from Mike Swarthout [3]

US experimental satellites

US experimental satellites were put in the segment 437.000-437.500 MHz.

wider bandwidth applications

In general we encourage the use of higher bands for wideband applications. The panel does not oppose experiments with a bandwidth exceeding 100 kHz e.g. digital video signals, 300 or 500 kHz wide.


There is a 25 year old agreement made between W2RS, Frank Bauer and Jan King. Nobody remembers the exact agreement! It is believed that 437.525-438.000 MHz is reserved for ARISS. In recent years the IARU Satellite Frequency Coordination Panel has made a number of exceptions. The arrangement with ARISS should be reviewed.

23 cm band

available for satellite use 1260.000-1270.000 MHz Earth-to-space

13 cm band

available for satellite use 2400.000-2450.000 MHz 2400-2403 narrow band (wifi channel 1 is at 2412)

higher frequency bands

  • 3.402-3.410 GHz
  • 5.650-5.670 GHz Earth-to-space
  • 5.830-5.850 GHz space-to-Earth
  • 10.450-10.500 GHz
  • 24.0480-24.0488 and 24.0490-24.0500 GHz
  • 47.088-47.090 GHz
  • 75.500-76.000 GHz and 77.500-77.501 GHz
  • 134.000-134.928 GHz
  • 248.000-248.001 GHz

Spacecraft planned above 1 GHz

by Graham G3VZV
We are sometimes asked whether there are any spacecraft planned that will be operating in the “microwave” bands. Here is a list that was recently (Q3 2017) compiled. I would be happy to receive corrections!

  • Fox-1C A 1U CubeSat in LEO. Will carry a 1.2 GHz uplink. Launch early 2018.
  • Fox-1D A 1U CubeSat in LEO. Will carry a 1.2 GHz uplink. Launch late 2017.
  • ESEO An ESA microsat with an AMSAT-UK payload. It will have a 1.2 GHz uplink for the transponder. Launch early 2018.
  • TY2-TY3-TY4-TY5-TY6 A constellation of five 6U CubeSats from Hunan Amateur Radio Club. Multiband radio experiments from a SSO. Include 2.4 GHz and 5.8 GHz downlinks and 5.6 GHz uplinks. A launch from China is planned for late 2017
  • HSKSAT A 3U CubeSat mission by the HSK Radio Club in Japan. Deploying from the ISS in January 2018. Will include a 1 Mbps 32APSK data downlink on 2.4 GHz.
  • P3E AMSAT-NA project for spacecraft in elliptical orbit. Will have 10 GHz down and 5.6 GHz up capability for data and transponder operations
  • P4A Eshailsat Qatari geostationary broadcast satellite with two amateur transponders 10 GHz down and 2.4 GHz up - total 8.5 MHz bandwidth. Launch mid 2018
  • P4B AMSAT-NA project two GSO with transponders 10 GHz down and 5.6 GHz up.
  • Lunar Communications Pathfinder ESA/Goonhilly/SSC project – 100 kg mothership in Lunar orbit possibly with 10 GHz down and 5.6 GHz up.
  • NASA Cube Quest Challenge Lunar Derby AMSAT-NA partnered with Ragnorak University. A 6U CubeSat with 10 GHz down, 5.6 GHz up – ranging and digital regenerative transponder
  • Deep Space Derby 6U – details awaited
  • TTU100 A 1U CubeSat, from the University of Tallinn, in SSO intended to demonstrate 10 GHz downlinks at data rates up to 20 Mbps.
  • TeikyoSat-4 A SSO mission from Teikyo University. Planning uplinks on 1.2 GHz and downlinks on 5.8 GHz
  • K2SAT A 3U CubeSat from Korea Airforce Academy. 2 Mbit QPSK Data downlink from SSO on 2.4 GHz

Doppler Shift

The apparent shift in frequency caused by the velocity of a satellite relative to an observer is proportional to both the absolute frequency of the transmitter and the satellite’s velocity.

The maximum Doppler shift for a given frequency is calculated to be:

  • 29.500 MHz ±0.744 kHz
  • 145.8 MHz ±3.68 kHz
  • 437.5 MHz ±11.03 kHz
  • 2405 MHz ±60.63 kHz

RR 1.147 on assigned frequency band: The frequency band within which the emission of a station is authorized; the width of the band equals the necessary bandwidth plus twice the absolute value of the frequency tolerance. Where space stations are concerned, the assigned frequency band includes twice the maximum Doppler shift that may occur in relation to any point of the Earth’s surface.

Earth Station

source: ITU Prague Small Sat Seminar 2015

Small satellite ground segment In conformity with No. 25.11 of the Radio Regulations (RR), any amateur-satellite operator shall set up at least one TT&C earth station (TA) to ensure that any harmful interference caused by emissions from its satellite can be terminated immediately (Article 22.1)

  • The TA TT&C station, has to be operated by an operator with a valid amateur license (duly authorized person) (Article 1.56 and 1.57 and Article 25) and callsign (Article 19)
  • The TT&C station is a critical part of the amateur-satellite systems with technical and operational challenges.
    • The visibility/access time (in-view window), of a satellite for a given Earth station is very short due to low orbit height and varies from approximately 10-15 minutes in the best case to no coverage at all for most of the 16 daily orbits. Small satellite operators may improve this situation by setting up an Internet connected special dedicated network of numerous/multiple remote amateur-satellite Earth stations (ARS-ES) along its satellite track (instead of one amateur-satellite Earth station, waiting for downlink opportunities). To increase a satellite availability,and to extend access time, and practically to have a global coverage (service area), capable to track and download telemetry or mission science data from the satellite at any place and any time if at least one “networked” Earth Station (ARS-ES) can see (in-view-window) the satellite, in this case the satellite service area has to be notified as XVE–VISIBLE EARTH.

In most cases the “networked” remote ARS-ES are outside of its satellite service area and Administrations very rarely notify this “extended service area” in the satellite filing to the Bureau. This missing information may generate a harmful interference situation when the amateur-satellite is operating in the bands shared with other services (Article 5.282) on a non-interference basis and the satellite is “active” (transmitting with a high power) outside of its service area. Administrations may authorize operation of these specific ARS-ES (TA), Which can receive the telemetry or mission data from any amateur-satellite and send this data by Internet to the particular amateur-satellite Mission Control Centre. However, to protect frequency assignments and gain international recognition of such ARS-ES (TA) in application of Resolution 642 (WARC-97), administrations should under Article 11.2 notify these ARS-ES (TA) to the Bureau. In contrary, it’s necessary to note that a remote transmission (uplink) by Internet and remote utilisation of ARS-ES TT&C earth command station for transmission (uplink) is prohibited, unless the Administrations concerned authorize it. (See Resolution 1 and ART 18).

Committed to Connecting the World RES-642 Relating to the bringing into use of earth stations in the amateur-satellite service. Procedures of Articles 9 and 11 are applicable to the amateur-satellite service (ARS). Characteristics of TA vary widely. Space stations in the ARS are intended for multiple access by TA in all countries. Coordination among ARS TA is without the need for formal procedures. The burden of terminating any Harmful Interference is placed on the ADM authorizing a space station in the ARS (Article 25.11) RES-642.

When an Administration intends to establish a satellite system in the ARS and wishes to publish information with respect to TA it may:

  • Communicate to the Bureau all or part of the information listed in APP 4; the Bureau shall publish such information in a Special Section
  • Requesting comments to be communicated within a period of four months after the date of publication
  • Notify under Articles. 11.2 to 11.8 all or part of the information listed in APP 44. The Bureau shall record it in a special list
  • This information shall include at least the characteristics of a typical TA having the facility to transmit signals to the space station to initiate, modify, or terminate the functions of the space station (Article. 25.11) RES-642