/GAINIMAGE gainImage [dB]
Specify the gain ratio of image to signal sidebands.
Real :: gainImage !
If "dB" is added after the value, the ratio is assumed to be in dB,
otherwise a decimal fraction.
Simple standard values for these gain ratios can be found on the IRAM
30-m web pages (Telescope Summary). If you need accurate values for the
single-pixel heterodyne receivers, you should measure them with:
CALIBRATE /GAINIMAGE receiverName