# Korean VLBI Network (KVN)

## Multi-frequency observations

Simultaneous multi-frequency observation is a unique capability of KVN with which we can calibrate out the short-term phase fluctuations at higher frequency data by referencing the phase solution obtained from lower frequency data. This phase referencing technique allows us to integrate the data for the time scale much longer than the coherent time scale of atmospheric phase fluctuation and so to observe weak sources at mm wavelength efficiently. For multi-frequency observations, we can select no more than 4 IFs among 8 IF signals ( = 4 receivers x 2 polarizations).

## Fast position switching observations

The slewing speed and acceleration rate of the KVN antenna are 3 deg/sec and 3deg/sec^2, respectively. Due to this high speed and acceleration rate, the KVN antenna can switch its pointing from target to calibrator at a short period.

## 2Gbps/4Gbps/8Gbps observation modes (NEW!)

2Gbps(1x512MHz), 4Gbps(2x512MHz), 8Gbps(4x512MHz) modes, which use fila10g and Mark6 recorder, have been fully evaluated in 2017. These modes are available for common use observations from 2017B semester. For multi-frequency observations, we can select 1,2 or 4 IFs among 8 IF signals ( = 4 receivers x 2 polarizations). Note that it is not allowed to assign multiple 512MHz streams for one IF.