Ham Radio Satellites
Amateur radio satellites, often referred to as “ham satellites,” are satellites that are specifically designed for use by amateur radio operators. These satellites provide a unique opportunity for hams to communicate over long distances, experiment with satellite technology, and engage in various forms of radio communication. Here’s an overview of ham radio satellites, how they work, and how to get started with satellite communication.
Types of Ham Radio Satellites
- Low Earth Orbit (LEO) Satellites: These satellites orbit the Earth at altitudes between 160 km and 2,000 km. They move quickly across the sky and are commonly used for amateur radio communication. Examples include:
- AO-91 (Fox-1A): A popular LEO satellite that supports FM voice and digital communication.
- SO-50: An FM satellite that is widely used by amateur radio operators.
- Geostationary Satellites: These satellites orbit the Earth at approximately 35,786 km and remain fixed over a specific point on the Earth’s surface. They provide continuous coverage to a specific area. An example is:
- AMSAT-NA’s Phase 4A: A future geostationary satellite planned for amateur radio use.
- High Altitude Platforms: These are not traditional satellites but can include high-altitude balloons or other platforms that provide communication capabilities.
How Ham Radio Satellites Work
- Transponders: Most ham radio satellites are equipped with transponders that receive signals on one frequency and retransmit them on another. This allows operators to communicate with each other via the satellite.
- Frequency Bands: Ham satellites typically operate on VHF, UHF, and sometimes microwave bands. Common frequency allocations include:
- VHF: 144 MHz (uplink) and 145 MHz (downlink)
- UHF: 432 MHz (uplink) and 435 MHz (downlink)
- Tracking: Because LEO satellites move quickly across the sky, operators need to track their position to establish communication. Software and apps are available to help predict satellite passes and provide real-time tracking.
Equipment Needed
- Transceiver: A VHF/UHF transceiver capable of operating on the frequencies used by the satellite.
- Antenna: Directional antennas, such as Yagi antennas, are commonly used to focus the signal toward the satellite. Dual-band antennas that cover both VHF and UHF are also popular.
- Tracking Software: Software or apps that can predict satellite passes and provide tracking information are essential for successful communication.
- Optional Equipment: Some operators use satellite rotators to automatically track the satellite’s movement across the sky.
Operating Techniques
- Listen First: Before transmitting, operators should listen to the satellite to understand the current activity and ensure the frequency is clear.
- Timing: Satellite passes are brief, typically lasting only a few minutes. Operators should be prepared to transmit quickly during the pass.
- Use of Simplex and Duplex: Some satellites allow for simplex operation (using the same frequency for both uplink and downlink), while others require duplex operation (different frequencies for uplink and downlink).
- Digital Modes: Some satellites support digital modes, allowing for text messaging and data transmission.
- Logging Contacts: Keeping a log of satellite contacts is important for tracking progress and confirming contacts.
Conclusion
Ham radio satellites provide a unique and exciting way for amateur radio operators to communicate over long distances and experiment with satellite technology. With the right equipment, techniques, and a bit of practice, operators can successfully make contacts via these satellites, expanding their horizons in the world of amateur radio. Whether you’re a seasoned operator or a newcomer, satellite communication offers a rewarding challenge and a chance to connect with fellow hams around the globe.