Observations with MERLIN at 408 MHz have been used to establish the low-frequency part of the spectra of more than a hundred compact radio sources taken from the part of the Jodrell Bank-VLA Astrometric Survey (JVAS) limited by 35{deg}<={delta}<=75{deg}. These sources were selected from JVAS and other catalogues to have convex spectra between 1.4 and 8.4GHz, characteristic of Gigahertz Peaked Spectrum sources. We have confirmed convex shapes of the spectra of 76 objects.