Increase in Interference Levels in the 45 – 870 MHz Band at the Spanish e-CALLISTO Sites over the Years 2012 and 2019

• Published in: Solar physics 2020-02, Vol.295 (2), Article 11
• Main Authors: Prieto, Manuel, Gordo, Javier Bussons, Rodríguez-Pacheco, Javier, Martínez, Agustín, Sánchez, Sebastián, Russu, Andrés, Monstein, Christian, Fernández, Rafael
• Format: Article
• Language: English
• Subjects: Astronomical instruments; Astronomy; Astrophysics and Astroparticles; Atmospheric Sciences; Broadband; Celestial bodies; Physics; Physics and Astronomy; Radio astronomy; Radio frequency interference; Solar observations; Solar physics; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Spectrometers; Spectroscopy
• ISSN: 0038-0938; 1573-093X
• DOI: 10.1007/s11207-019-1577-5

Two sets of radio-frequency interference (RFI) measurements in the 45 – 870 MHz band are compared. The first set was taken in 2012 at various sites in the province of Guadalajara (Spain) as part of a worldwide site-testing campaign for the deployment of an international network of solar radio-spectrometers, the Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory (e-CALLISTO) array. Peralejos de las Truchas was found to be an ideal location, even for high-sensitivity non-solar observations, with the lowest interference levels ever measured in the framework of e-CALLISTO. The same set of measurements have been repeated seven years later using the same experimental setup at the same locations. The results presented in this article show that the RFI levels after seven years have notably increased, at some places by a factor of two, thereby placing at risk broadband spectroscopic radio-astronomy studies from the ground.