Satellite Uplink Frequency Greater Than Downlink

Io 86 lapan a2 145 880 mhz.

Satellite uplink frequency greater than downlink. The description provided here is imprecise as the exact configuration can vary widely. The term uplink chain is used to refer to the series of pieces of equipment that are used to produce a radio frequency signal for sending out data. The downlink chain is built using nearly the same equipment in reverse order. Now as would have thought separate frequency bands are always allocated for uplink and downlink signals often separated by a gap maybe for future allocation since the span of guard bands are relatively very less compared to the actual information carrying bands e g 100 khz guard bands in case of gsm 900 where the uplink and downlink.

Take a look at the drawing below and note the path of devices on the left hand. Now as would have thought separate frequency bands are always allocated for uplink and downlink signals often separated by a gap maybe for future allocation since the span of guard bands. If both uplink and downlink shared the same frequency. So we require more bandwidth in dl than in ul and it can be attained only if dl freq.

For real time updates about which mode the satellite is in see the amsat live oscar satellite status page. Pertaining to radiocommunication service an uplink ul or u l is the portion of a feeder link used for the transmission of signals from an earth station to a space radio station space radio system or high altitude platform station. The satellite transmitter generates a signal that would jam its own receiver. Generally people download more than upload however its converging now.

This point is from user perspective. Satellite is in a low inclination low earth orbit and not visible north of about 30 degrees north or south of 30. Pertaining to gsm and cellular networks the radio uplink is the transmission path from the mobile station cell phone to a base station cell site. Trying to receive and transmit an amplified version of the same uplink waveform at same satellite will cause unwanted feedback or ring around from the downlink antenna back into the receiver.

5925 mhz to 6425 mhz is uplink band where as 3700 to 4200 mhz is downlink band. Hence downlink frequency should be greater than uplink frequency.