Integrated spectra of the radio sources in the A3528 cluster complex. Top row: Flux densities were measured after convolving all the frequencies at the same resolution. Different dashed lines in each panel are colour-coded based on the region where the flux density was extracted (see bottom panels), and describe the fitted α (see Column 6 in Table 4). Bottom row: uGMRT Band 3 images of the three clusters (from left to right: A3528N, A3528S and A3532) at ∼12″ (see beam in the bottom-left corner of each panel). Radio contours start at the 3σ_rms level, which was used as reference for drawing the regions.