SOLAR SYSTEM

Detailed explanation-1: -Explanation: The original signal being transmitted from the earth station to the satellite is called the uplink, and the re-transmitted signal from the satellite to the receiving stations is called the downlink. Usually, the downlink frequency is lower than the uplink frequency.

Detailed explanation-2: -In satellite communication, the uplink frequency is higher than the downlink frequency because the attenuation level increase with an increase in frequency. The power at the ground station (Base Station) is more than compared to the power available at the satellite.

Detailed explanation-3: -So, in order to overcome the attenuation, MS has to transmit on high power. But due to the constraint on the amount of energy available on the MS battery, this approach is not feasible. Hence, downlink frequency should be greater than uplink frequency. This point is from user perspective.

Detailed explanation-4: -Ku-band (12–18 GHz) Used for satellite communications. In Europe, Ku-band downlink is used from 10.7 GHz to 12.75 GHz for direct broadcast satellite services, such as Astra.

Detailed explanation-5: -The communication going from a satellite to ground is called downlink, and when it is going from ground to a satellite it is called uplink. When an uplink is being received by the spacecraft at the same time a downlink is being received by Earth, the communication is called two-way.

Detailed explanation-6: -For cellular devices such as smartphones & tablets, uplink and downlink pertain to the data speed and coverage we know as 4G/LTE, and newer radio frequencies such as 5G. Signal coming to your phone from the cell tower is known as the downlink. Signal leaving your phone back to the cell tower is known as the uplink.