The combined use of digital recorders and a fast Fourier transform analyzer made it possible for us to carry out wideband field analysis direction finding measurements for whistlers at low latitude (geomagnetic latitude 25¿N). It is found that there is a negligibly small frequency dependence of the ionospheric exit point and polarization of daytime whistlers during each occurrence peak with duration of about 2 hours, which lends further support to their propagation in a field-aligned duct in the magnetosphere for each occurrence peak. ¿ American Geophysical Union 1989