Abstract

The VLA’s new Lowband system has been employed to measure the flux densities of seven proposed standard flux density calibration sources between 220 and 460 MHz, based on the Baars et al. (1977) expression for Cygnus A. Using these data, legacy VLA 74 MHz data, and the results of Perley and Butler (2013), we generate interim polynomial expressions for the spectral flux densities of 3C123, 3C196, 3C286, and 3C295 valid between 50 MHz through 50 GHz.