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K. P. Stewart, P. C. Crane, N. Paravastu, B. C. Hicks (Naval Research Laboratory), A. Theodorou, R. M. Price, Y. M. Pihlstrom (University of New Mexico), T. S. Bastian (National Radio Astronomy Observatory), D. E. Gary (New Jersey Institute of Technology)
An initial survey of the radio-frequency environment at the site of the Long Wavelength Demonstration Array (LWDA) has been performed using a measurement protocol developed for both the Long Wavelength Array (LWA) and the Frequency Agile Solar Radiotelescope (FASR). The measurements cover the frequency range from 25 MHz to 18 GHz to include the LWA (23-80 MHz) and FASR (30 MHz-30 GHz). Measurements were obtained nearly continuously for a week to characterize the day/night and weekday/weekend variations expected for many sources of RFI. The equipment, antennas, and protocols are suitable for measuring strong RFI that potentially threatens the linearity of radio-astronomical receivers and may therefore rule out possible sites or influence the design of the receivers. (Weak RFI which may obscure weak signals of interest is beyond the capabilities of these measurements.) The protocol seeks only to identify RFI originating from terrestrial sources; RFI from satellites and astrophysical sources is assumed to be site independent and not a factor in site selection. Therefore, the receiving antennas provide azimuthal coverage in the direction of the horizon. This first survey, conducted prior to the start of LWDA construction, establishes a baseline for the later identification of any self-generated interference from the LWDA and its mitigation to ensure no adverse effect on the operations of the VLA.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.