What role does a radio receiver play in a radio telescope?

In a radio telescope, the radio receiver—also known as a radiometer—serves as a critical component responsible for amplifying and detecting the weak cosmic radio signals collected by the telescope's antenna.1

The receiver plays several essential roles in the operation of the instrument:

• Signal Processing: It receives incoming signals transferred from the antenna's feed (often a waveguide horn). To achieve the highest possible sensitivity, modern systems utilize solid-state amplifiers that are cooled to extremely low temperatures, which significantly reduces internal noise.1
• Sensitivity and Bandwidth: The receiver's ability to measure weak sources depends on its sensitivity and, for broadband continuum emission, its bandwidth. By utilizing advanced technology, receivers allow astronomers to detect faint signals that would otherwise be masked.1
• Data Analysis: Receivers are used to measure both broad-bandwidth continuum radiation and narrow-bandwidth spectroscopic features. Modern systems can observe multiple frequencies simultaneously by dividing signals into thousands of separate channels. These signals may be converted into digital form for analysis via Fourier transforms or processed through filter banks to produce detailed spectral data.1