Average pulse profiles of the three pulsars. The profile changes with sky frequency is clearly evident. The profile for PSR B1133+16 at 163.5 MHz is not shown because it was too corrupted by RFI. The profiles are shown at 809, 580, 460 μs time resolution for PSRs B1112+50, B1133+16 and B0031−07 respectively. All profiles are normalised by the maximum flux density in the band and are aligned at the phase of maximum intensity in each band. Profiles at 116.75 and 130 MHz have comparatively more noise because up to  ~15% of pulses were removed to reject RFI.