Korean VLBI Network (KVN)

Receiver Noise Temperature

Following table shows typical noise temperature of each band. Since the calibration chopper is located before the quasi-optics as shown in the quasi-optics figure, the loss of quasi-optics contributes to receiver noise temperature instead of degrading antenna aperture efficiency. Therefore, the noise temperature in the table includes the contribution due to the quasi-optics losses.

Band Trx (K)
22 30 - 40
43 70 - 80 (40-50 for Ulsan)
86 80 - 100
129 50-80

The receiver noise temperatures of three stations are similar to each other except 43GHz band. Note that the noise temperature of the Ulsan 43GHz receiver is lower than the other stations. This is mainly due to the different type of thermal isolator at Ulsan, which is used to reduce heat flow from the feed horn in room temperature stage to cryogenic cooled stage more effectively.

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Korean VLBI Network (KVN)