Cal -- source status: We consider a source suitable as a calibrator if 1) the number of good X/S pairs of observations is 8 or greater in order to rule out the possibility of a group delay ambiguity resolution error; and 2) position error before reweighting is less than 5 mas. It was found that usually 8 observations at the VLBA is sufficient to get positions with errors less than 5 mas. If the errors are significantly greater, this means that the source was not detected at long baselines, and therefore, we do not possess information on whether the source can be detected when used as a phase referencing calibrator.