  The low-latitude ionosphere is a dynamic region with a wide range of
disturbances in temporal and spatial scales. The Giant Metrewave Radio
Telescope (GMRT) situated in the low-latitude region has demonstrated its
ability to detect various ionospheric phenomena. It can detect total electron
content (TEC) variation with precision of 1 mTECU and also can measure TEC
gradient with an accuracy of about $\rm7\times 10^{-4}\,TECU\,km^{-1}$. This
paper describes the spectral analysis of previously calculated TEC gradient
measurements and validates them by comparing their properties using two bands.
The analysis tracked individual waves associated with medium-scale traveling
ionospheric disturbances (MSTIDs) and smaller waves down to wavelengths of
$\sim$ 10 km. The ionosphere is found to have unanticipated changes during
sunrise hours, with waves changed propagation direction as the sun approached
the zenith. Equatorial spread\,$F$ disturbances during sunrise hours is
observed, along with smaller structures moving in the same direction.
