We present the results of the first low frequency measurements of
the flux densities of a large sample of millisecond pulsars (MSPs)
at 102 and 111 MHz. Combining our observations with data at higher
frequencies borrowed from the literature, we constructed the
spectra of 30 MSPs in the 0.1 to 4.8 GHz frequency range. Our flux
density measurements extend the known spectra of MSPs to the
lowest frequency to date.
The coverage of a low frequency range allows us to search for low
frequency turn-over, which is often observed for normal pulsars.
We find that spectra of MSPs differ from those of normal pulsars,
showing no low-frequency turn-over typical of normal pulsars. We
suggest that the geometry of the radio emission region of MSPs
differs from that of normal pulsars: the magnetic field
configuration in MSPs' magnetospheres may deviate from that of a
pure dipole and/or the radio emission region may be radially
compressed.
Monochromatic luminosities at this low frequency and the integral
luminosity over the 0.1-4.8 GHz frequency range were determined
and their dependence on other pulsar parameters analyzed
