The frequency used to transmit a signal from a satellite to a receiving Earth…

Concept

Satellite communication links are named by their direction relative to the Earth: radio transmission toward a spacecraft is an uplink, while radio transmission toward the ground is a downlink.

The same directional naming applies whether the carrier transports commands, telemetry, or payload data.

Application

Here the transmitter is the satellite and the receiver is the Earth station, so the signal travels toward the ground. The associated carrier therefore uses the downlink frequency.

Contrast

• Uplink frequency applies to the opposite direction, from an Earth station toward a satellite.

• Backlink frequency is chiefly a web-link term, not the standard Earth-relative term for a satellite radio link.

• Forward link frequency is a system-role term whose endpoint convention must be stated; it is not the fixed Earth-relative label sought here.

• Downlink frequency names the satellite-to-Earth leg described in the stem.

Cross-check

NASA and ITU terminology both distinguish Earth-to-space transmission as uplink and space-to-Earth transmission as downlink.

Result

The required value is downlink frequency.