If you are connected to us via Radio-SkyPipe at 0 hours Universal Time (UT) every day, you will see our receiver go through an automated calibration process. When this happens the antenna is removed from the receiver and a calibrated noise source is connected instead. This device produces a sequence of wide band noise outputs of known strength. It then becomes possible to estimate the strength of the signals we receive through the day by comparing their Y values to these known Y values.
Often in radio science we calibrate noise signal levels in terms of equivalent temperature. Roughly this is the noise produced by a hypothetical resistor raised to some temperature. We cant really raise a resistor to the high temperatures used. It would burn up. We use a diode or other noise producing device to make the noise signal for calibration. Stating with the lowest step the noise temperatures you see on the chart above are:
290 Deg Kelvin
12,500 Deg
25,000 Deg
50,000 Deg
100,000 Deg
200,000 Deg
400,000 Deg
800,000 Deg
1.6 million Deg
3.2 million Deg
6.4 million Deg