Technical Article

The Small Phased Array DEmonstrator (SPADE)

Description and first results

¹ Solar Terrestrial Center of Excellence – Royal Observatory of Belgium, Avenue Circulaire 3, 1180 Brussels, Belgium
² Center for mathematical Plasma Astrophysics, KU Leuven, Leuven, 3000 Belgium

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 2 December 2025
Accepted: 18 May 2026

Abstract

We present the Small Phased Array DEmonstrator (SPADE), a compact phased array spectrograph designed for the monitoring of solar activity in the decameter range, where a majority of bursts of interest for solar physics and space weather occur. Unlike other existing phased arrays, SPADE operations like Sun tracking and spectra productions are made entirely digitally, and rely on the use of open source library software and commercial generic software defined radio receivers. In this paper, we describe the instrument and its associated software and present the first observations of the Sun and the Jovian magnetosphere conducted between September and December 2024. For the solar observations, in particular, we highlight the capacities of the instrument in terms of temporal and frequency resolution, making it capable of addressing science topics like turbulence in the coronal medium and propagation effects affecting radio waves, which are currently only accessible by larger but non-solar dedicated phased arrays.