A 50 MHz System for GMRT

TL;DR

This paper presents the development and initial testing of a new 50 MHz system for GMRT, aiming to enhance low-frequency radio imaging with increased sensitivity and new observational capabilities.

Contribution

It introduces a new 50 MHz receiver system for GMRT, including hardware and software correlator developments, with initial promising observational results.

Findings

Enhanced sensitivity over existing systems

Successful initial observations of bright radio sources

Implementation of new correlator and recording systems

Abstract

This paper describes a 50 MHz system being developed for GMRT to provide imaging capability in the frequency range 30-90MHz. Due to its larger collecting area and higher antenna efficiency, the low frequency GMRT system will be several times more sensitive than the present 74 MHz VLA system and is likely to remain a competitive instrument in this frequency band. In the first phase of this project, receiver systems consisting of V-dipole feeds and front-ends have been installed on four of the thirty GMRT antennas. Test observations were carried out on a number of bright 3C sources. The initial results are encouraging. This paper will also describe results of simultaneous observations carried out using the existing GMRT correlator, the new GMRT software correlator and a system employing digitization and direct recording of signals at two antenna bases.