# Radio Interferometer Telescope

 Subject classification: this is a physics resource.
 Subject classification: this is an astronomy resource.
 Subject classification: this is an education resource.
 Educational level: this is a research resource.
 Educational level: this is a tertiary (university) resource.

## Introduction

This project deals with making a astronomical interferometer (a type of a radio telescope) based on the techniques of aperture synthesis. This telescope is designed to work at a radio frequency of 74 MHz.

The basic idea is to measure complex cross-correlation coefficients between voltage signals from two antennas separated by a distance, ${\displaystyle b}$. This technique, called interferometry, is used to obtain higher angular resolution, which may not be attainable due to modest sizes of individual antenna (or dishes) involved in observations.

## Methodology

We plan to use half-wave dipole antennas to sense electromagnetic waves from astronomical sources at ${\displaystyle 74}$ MHz. This signal will be down-converted to ${\displaystyle 1.9}$ MHz using a mixer, after necessary amplification. A small band around 73.9 MHz, of about ${\displaystyle 0.25}$ MHz will be recorded using a direct-voltage recorder system. This raw, 2-bit quantized data will be stored on a PC for a later processing by customized computer programs.

These programs have been termed as `software correlator'. Our code for cross-correlation is based on lookup-table approach, details of which will be available on a separate page titled BITS Correlator.