Profile evolution of the three MSPs detected in the LBA frequency range of 38.2–77.2 MHz. The grey profile on top of each panel is the average profile within the 39-MHz wide band. All profiles are from 1-h LBA observations. There are 64 bins in the profiles of PSRs J0030+0451 and J0034−0534 and 128 bins in the profiles of PSR J2145−0750. The numbers on the left in each panel show the central frequency in MHz of the corresponding 7.8-MHz sub-band.