  Fluctuations in the flow velocity and magnetic fields are ubiquitous in the
Solar System. These fluctuations are turbulent, in the sense that they are
disordered and span a broad range of scales in both space and time. The study
of solar wind turbulence is motivated by a number of factors all keys to the
understanding of the Solar Wind origin and thermodynamics. The solar wind
spectral properties are far from uniformity and evolve with the increasing
distance from the sun. Most of the available spectra of solar wind turbulence
were computed at 1 astronomical unit, while accurate spectra on wide frequency
ranges at larger distances are still few. In this paper we consider solar wind
spectra derived from the data recorded by the Voyager 2 mission during 1979 at
about 5 AU from the sun. Voyager 2 data are an incomplete time series with a
voids/signal ratio that typically increases as the spacecraft moves away from
the sun (45% missing data in 1979), making the analysis challenging. In order
to estimate the uncertainty of the spectral slopes, different methods are
tested on synthetic turbulence signals with the same gap distribution as V2
data. Spectra of all variables show a power law scaling with exponents between
-2.1 and -1.1, depending on frequency subranges. Probability density functions
(PDFs) and correlations indicate that the flow has a significant intermittency.
