2001 The sband narrow cals have a single diode that feeds both polarizations. This is the lcorcal (if you select any other type of cal with sbn you will always get lcorcal). I'm not sure the date of the original cal measurements. On 14oct03 the polarizations were switched. Measurements of the sbn cals. date . ... New receiver installed . ... installed 10apr06 . ... Pre 14oct03 : polA 6.9, polB 6.76. ... These were the values used until the new values were installed on 10apr06 . ...