An automatic radio interference monitor for the National Radio Astronomy Observatory Very Large Array

The National Radio Astronomy Observatory (NRAO) operates the Very Large Array (VLA) Radio Observatory on the Plains of San Augustin in New Mexico, and the Very Long Baseline Array (VLBA) with 10 antenna locations from Hawaii to St. Croix. Harmful radio frequency interference (RFI) is a growing problem for the VLA and the VLBA, and for that matter, all Earth-based radio astronomy. The paper describes an automated monitor system that has been recently installed at the VLA for use in identifying and cataloging RFI. The operation of the VLA and VLBA are summarized and the reason interference is a problem is explained. Initial results of the monitoring are included as are plans for future expansion of the program.