Radio pollution: the invisible threat to radio astronomy

Impact of Cognitive Radio on Radio Astronomy

The introduction of new communication techniques requires an increase in the efficiency of spectrum usage. Cognitive radio is one of the new techniques that fosters spectrum efficiency by using unoccupied frequency spectrum for communications. However, cognitive radio will increase the transmission power density and cause an increasing level of Radio Frequency Interference (RFI), which may impa...

Radio Frequency Interference Mitigation in Radio Astronomy

Radio Astronomy with RASDR2

The RASDR design team is releasing a software-defined receiver (SDR) for radio astronomy called RASDR2 7 . The receiver consists of two high-density circuit boards -a wide-band femtocell 8 chip on the front end analog interface MyriadRF board 9 linked to a DigiRed digitization and function control board -coupled to a computer via either a USB2 or USB3 interface. RASDRViewer software runs in a W...

National Radio Astronomy Observatory

Measurements of microwave attenuation at room temperature and 4.2 K have been performed on some conductors commonly used in receiver input circuits. The reduction in loss on cooling is substantial, particularly for copper and plated gold, both of which showed a factor of 3 loss reduction. Copper passivated with benzotriazole shows the same loss as without passivation. The residual resistivity r...

Techniques of Radio Astronomy

This chapter provides an overview of the techniques of radio astronomy. This study began in 1931 with Jansky’s discovery of emission from the cosmos, but the period of rapid progress began fifteen years later. From then to the present, the wavelength range expanded from a few meters to the sub-millimeters, the angular resolution increased from degrees to finer than milli arc seconds and the rec...