Solar
radio type IV bursts can sometimes show directivity, so that no burst
is observed when the source region in located far from the solar disk
center. This has recently been verified also from space observations, at
decameter wavelengths, using a 3D-view to the Sun with STEREO and Wind
satellites. It is unclear whether the directivity is caused by the
emission mechanism, by reduced radio wave formation toward certain
directions, or by absorption/blocking of radio waves along the line of
sight. We present here observations of three type IV burst events that
occurred on 23, 25, and 29 July 2004, and originated from the same
active region. The source location of the first event was near the solar
disk center and in the third event near the west limb. Our analysis
shows that in the last two events the type IV bursts experienced partial
cut-offs in their emission, that coincided with the appearance of
shock-related type II bursts. The type II bursts were formed at the
flanks and leading fronts of propagating coronal mass ejections (CMEs).
These events support the suggestion of absorption toward directions
where the type II shock regions are located.