KaVA has provided two correlation modes with 8 IFs 32 MHz and 16 IFs 16 MHz, called as the C4 and C5 modes, respectively.
To obtain the accurate amplitude values across the all frequency channels, however, the number of basebands (or IFs in AIPS data handling) yielded by the digital filter unit (DFU)
is better to be reduced because the amplitude losses mainly occur at the edges of each baseband.
This reduction is especially helpful to observe continuum sources, such as active galactic nuclei (AGN).
The C2 mode, which has 2 IFs 128 MHz, therefore, is opened but at only Q-band in 2018A.
Note the following two matters:
there are some amplitude slopes mainly at VERA stations
(Figures 12 and 13 in the VERA status report: http://veraserver.mtk.nao.ac.jp/restricted/CFP2018A/status18A.pdf),
which must be corrected by all the gain calibration procedures (AIPS tasks ACCOR, BPASS, and APCAL);
multiply the scaling factor to recover the quantization loss (1.3 for Daejeon correlator) .