G/T is the figure of merit for a satellite system.

G is the Receive antenna gain.

T is the system noise temperature.

System noise temperature = antenna noise temperature + Receiver noise temperature (LNA)

Antenna noise temperature is the noise power seen at the receive output of the antenna. (To LNA)

If you are not measuring with an LNA or Receiver then the System noise temperature = antenna noise temperature. This is not a representative value for calculating G/T since the G/T relates to the receive performance of both antenna and receiver.

To convert to dB, T dB = 10 log(T kelvin)

If both are measured in dB then the G/T = Ant Gain - System Noise Temp.

Edited by Satcoms UK - 16/April/2015 at 22:51]]>