1997A&A...321..519S

Considering the geometry of the hollow-cone model of radio pulsar emission in detail, one is led to the conclusion that several well-known observed effects may be explained quite easily purely on geometrical terms. It can be shown e.g. that the appearance of outriders at high frequencies and a steepening of the whole spectrum (cut-off) must be expected for certain geometrical situations as well as variations in component spectra, e.g. a steepening of the central (core) component. These effects appear in addition to the presumably also existing physical variations with frequency.