Source: China Radio Management
Author: Liu Mingxing, Zhao Zhe, Zhang Ning
Editor's Note:
In early 2021, experts at the National Radio Monitoring Center compiled a series of articles by Keith Baker (call sign KB1SF/VA3KSF), a well-known American amateur radio enthusiast and former chairman of AMSAT, which appeared in the "Monitoring Times," and created a dedicated column titled "Exploring Amateur Satellite Communication" on the WeChat public account "China Radio Management." In 2021, to coincide with the tenth World Radio Day on February 13th, we selected excerpts from the center's book, "Amateur Satellite Communication," providing a brief overview of the history and development of amateur radio and satellite communication, relevant frequency bands, related radio management policies, and existing amateur satellite information. This resulted in the publication of a series of original科普 articles titled "Original科普《Amateur Satellite Communication》." Both series of articles were widely praised. Recently, we have compiled the history of the development of amateur satellite communication and global amateur satellite situations, combining relevant content from the book "Amateur Satellite Communication," to launch a series of excerpts titled "Introduction to Global Amateur Satellites" (selected), which will be serialized on the WeChat public account "China Radio Management" starting today for two days, with the aim of providing in-depth information about amateur satellite communication.
First Part: Overview of Amateur Satellites
Chapter 2: Amateur Satellites in the United States
Chapter 3: Japanese Amateur Satellites
Chapter 4: Amateur Satellites in China (Part 1)
Fifth Section: Chinese Amateur Satellites (Continued)
Chapter Six: A Typical Abandoned Amateur Satellite
First Part: Overview of Amateur Satellites
The primary function of amateur satellites is to relay signals or transmit voice, and we can categorize the status of these satellites into five states: transmitter operating, International Space Station (voice) normal, only beacon, no signal, and conflict report (Figure 1). This status information is updated in real-time by amateur enthusiasts worldwide, and they voluntarily share this information so that amateur satellite communication enthusiasts can develop communication plans based on the real-time status of the satellites.
Figure 1: Real-time communication status of in-orbit amateur satellites
1. A Brief History of Amateur Satellite Development
In 1957, the Soviet Union launched Sputnik 1, the first artificial Earth satellite, marking the beginning of the human space age. Four years later, a satellite developed by amateur radio enthusiasts, OSCAR-1, was launched from a U.S. Air Force base in California. This not only demonstrated that amateur radio enthusiasts were capable of technical collaboration with aerospace launch agencies, developing, tracking, and controlling their own satellites, and collecting and processing relevant scientific and engineering data; it also marked the entry of amateur radio communication into the space age. To date, hundreds of amateur satellites have been successfully launched by amateur radio enthusiasts around the world. Currently, the OSCAR identification number has reached MO-46, but there are approximately less than 30 operational amateur satellites. Many new generation OSCARs are currently under development or manufacturing and testing. Amateur radio enthusiasts in various countries can use these amateur satellites to conveniently experiment with and communicate using various communication methods. In recent years, amateur satellites have also been used by university technology organizations, for emergency communications during natural disasters, and for high-tech experiments.
AMSAT-OSCAR satellite development stages:
The satellites launched in the first phase typically had a short lifespan and were only used for simple signal transmission experiments. Notable examples from this period include OSCAR-1 through OSCAR-5. The OSCAR-1 satellite, launched on December 12, 1961, remained in orbit for only 22 days, with over 570 amateur enthusiasts in 28 countries receiving its signals. The OSCAR-3 satellite remained in orbit for 18 days, and received signals from over 1000 amateur enthusiasts in 22 countries.
Figure 2: Lance Ginna（K6GSJ）And compared to the first amateur radio satellite, OSCAR-1.
The satellites launched in the second phase not only had a long lifespan (most were used for over 10 years), but also included linear transponders, digital automatic transponders, and other various communication devices. Many of the satellites currently in use, such as AO-6 to AO-8, the Russian RS series, and the Japanese FujiOSCAR series, were launched during this phase. Due to their low orbits, these satellites transmit very strong signals to the ground, making it possible to conduct satellite communication experiments with simple equipment. However, the orbital periods of these low-orbit satellites are very short, typically no more than 150 minutes, and the time they spend above a given radio frequency is only a few minutes each pass.
The satellites launched in the third phase are characterized by their higher orbits, and like those launched in the second phase, they also have a long lifespan and can be used with various communication methods. Key examples include the already launched AO-10, AO-13, and AO-40 satellites. The longer orbital period of these high-orbit satellites compared to those in previous phases significantly increases communication time; furthermore, their higher orbits allow them to cover a larger area, reaching approximately one-third of the Earth's surface when at their farthest point.
Figure 3: Coverage map of QO-100, the first amateur satellite in GSO (Geostationary Orbit), Es'hail-2.
The Russian RS series satellites are a good choice for those venturing into amateur satellite communication. Since October 26, 1978, Russia has launched over ten amateur satellites (RS-1 to 17), including Radio Sputnik-1. However, the early satellites' orbits at an altitude of 1700 kilometers were located within the Van Allen radiation belt, and the high-energy particle streams there caused significant damage, preventing these satellites from reaching their intended lifespan. As a result, since RS-10 and RS-11, the RS series satellites have been launched into lower-radiation orbits around 1000 kilometers.
Since 1961, amateur radio enthusiasts have been responsible for creating a constellation of approximately 150 orbital space satellites. These satellites are typically developed in collaboration with academic institutions and launched under the support of space and satellite organizations. Amateur satellites can be divided into: frequency-modulated relay satellites, forwarder satellites, and digital satellites. The existing classification of satellites is as follows:
Frequency hopping repeater satellites: SO-50 (SaudiSat-1C), AO-91 (RadFxSat / Fox-1B), LilacSat-2 (CAS-3H)IO-86 (LAPAN-A2) PO-101 (Diwata-2), AO-27, ISS Crossband Repeater
Relaying satellite: AO-7, FO-29 (JAS-2)AO-73 (FUNcube-1), XW-2A (CAS-3A)XW-2B (CAS-3B) XW-2C (CAS-3C)XW-2D (CAS-3D) XW-2F (CAS-3F)LO-87 (LUSEX / ?uSat-1), EO-88 (Nayif-1 / FUNcube on Nayif-1), CAS-4A, CAS-4B, FO-99 (NEXUS) 、JAISAT-1 、TO-108 (CAS-6) RS-44, QO-100 (Es'hail-2 / P4A) (25.9°E).
Digital satellites: FalconSAT-3, NO-44 (PCsat), NO-84 (PSAT)IO-86 (LAPAN-A2) AISAT-1, NO-103 (BRICSAT2)No. 104 (PSAT2)ISS Frequency Summary
Figure 4: NO-104 effect demonstration
2. International Organization for Amateur Satellites
For over 60 years, AMSAT groups in North America, Europe, and other regions have played a significant role in space science, space education, and space technology, greatly advancing the field to its current level. There is no doubt that the work of amateur radio engineers around the world will continue to have a profound and positive impact on the future of amateur radio and other government, scientific, and commercial activities.
1) The Radio Amateur Satellite Corporation (AMSAT): As a non-profit research and education organization, AMSAT was founded in Washington, D.C., in 1969. It provides amateur satellite design, construction, testing, and operation services, as well as conducting scientific education through the publication of technical books, dissemination of information, and provision of internet services for radio enthusiasts and students worldwide. Over the past 50 years, the work of AMSAT volunteers around the world has had a profound and positive impact on satellite communications and space exploration, playing a significant role in promoting the development of space science, space education, and space technology.
2) French-speaking amateur radio satellite organization（AMSAT-FR）: The aim is to develop amateur satellite and space services, particularly for French-speaking countries. It provides support to amateur radio enthusiasts and operators, enabling them to use amateur radio satellites to implement, guide, or advise on space and aviation projects involving amateur or organic entities (e.g., satellites, launch vehicles).
3) The ARISS (Amateur Radio on the International Space Station) program allows students from around the world to directly communicate with astronauts aboard the International Space Station, fostering their interest in science, technology, engineering, and mathematics careers, and providing them with opportunities to engage with amateur radio and related technologies.
3. Applications of amateur satellites are being explored.
Article 1.56 of the International Telecommunication Union's "Radio Regulations" clearly defines satellite amateur radio for use by amateur radio enthusiasts for self-training, mutual communication, and technical research.
Table 1: Overview of Existing AMSAT Projects
Number
Project Name
Project Overview
Note:
1
AMSAT Education
For those with ambitious dreams and a passion for science, technology, engineering, and mathematics (STEM).（STEM）For young men and women interested in aviation and advanced communications, AMSAT offers a wealth of opportunities to become the next generation of innovators in these fields.
Self-training
2
Cube Star Simulator
The AMSAT CubeSat Simulator is a project of the AMSAT Education Liaison Department. It is a low-cost satellite simulator that runs on solar panels and batteries, transmitting U HF radio telemetry data. It has a 3D printed frame that can be extended with additional sensors and modules.
Self-training
3
ARISS
ARISS allows students around the world to experience the excitement of communicating directly with astronauts working on the International Space Station via amateur radio. The first flight unit of the next-generation ARIS interoperable radio system was launched to the International Space Station in March.
Mutual communication
4
GOLF Cube Star Project
The next phase of the AMSAT CubeSat program, which is also a key component of AMSAT's strategic goals, involves high-altitude, wide-access satellite missions. GOLF will serve as a testbed for new technologies, including software-defined microwave transponders and attitude determination and control systems. The first Golf cube satellite, the "Golf Ball Seat" (technical evaluation environment), is scheduled to be completed by the end of this year.
Technical research
The current status of amateur satellite applications is as follows:
Self-training: Amateur satellite enthusiasts both domestically and internationally are improving their radio communication skills by building their own antennas and tracking the passage of satellites, as well as participating in amateur satellite manufacturing projects. This continuous effort helps them to constantly improve their radio proficiency.
Inter-satellite communication: Amateur satellite enthusiasts communicate over long distances using satellites. According to AMSAT records, the current longest communication distance is 18730 kilometers, as reported in 2003.
Technical Research: Since the first amateur satellite launch, business satellites have made significant progress, with contributions from radio enthusiasts worldwide. From short-lived amateur satellites to large satellites that allow users to communicate across one or more continents simultaneously, this has spurred continuous technical research by amateur enthusiasts.
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