  We analyze the 26 November 2005 solar radio event observed
interferometrically at frequencies of 244 and 611 MHz by the Giant Metrewave
Radio Telescope (GMRT) in Pune, India. These observations are used to make
interferometric maps of the event at both frequencies with the time cadence of
1 s from 06:50 to 07:12 UT. These maps reveal several radio sources. The light
curves of these sources show that only two sources at 244 MHz and 611 MHz are
well correlated in time. The EUV flare is more localized with flare loops
located rather away from the radio sources. Using the SoHO/MDI observations and
potential magnetic field extrapolation we demonstrate that both the correlated
sources are located in the fan structure of magnetic field lines starting from
a coronal magnetic null point. Wavelet analysis of the light curves of the
radio sources detects tadpoles with periods in the range P = 10-83 s. These
wavelet tadpoles indicate the presence of fast magnetoacoustic waves that
propagate in the fan structure of the coronal magnetic null point. We estimate
the plasma parameters in the studied radio sources and find them consistent
with the presented scenario involving the coronal magnetic null point.
