What mode of transmission is commonly used by amateur radio satellites?

Amateur radio satellites often utilize multiple modes of transmission to accommodate different types of communication and to allow a greater variety of operators to connect. Both FM (Frequency Modulation) and CW (Continuous Wave) have specific applications in satellite communication.

FM is commonly used for voice operations on some amateur radio satellites due to its relative simplicity and effectiveness in providing clear audio signals over short distances typical for satellite communication. This is especially prevalent in low Earth orbit satellites where the signal propagation is more consistent.

CW, which is often employed in the form of Morse code, allows for efficient communication over limited bandwidth, making it suitable for weak signal operations and providing opportunities for digital data transmission as well.

Single Sideband (SSB) is another mode utilized in satellite communications, particularly for operators who may wish to engage in voice communication over longer distances, especially during contests or special events.

Since all these modes—SSB, FM, and CW/data—are utilized in various amateur radio satellites, the correct choice is that all these choices are correct, reflecting the versatility and adaptability required in amateur radio operations involving satellites. This multi-modal approach allows operators to select the best mode based on their equipment, the characteristics of the satellite, and the type of communication they wish to pursue