  The primary goal of the pulsar timing array projects is to detect
ultra-low-frequency gravitational waves. The pulsar data sets are affected by
numerous noise processes including varying dispersive delays in the
interstellar medium and from the solar wind. The solar wind can lead to rapidly
changing variations that, with existing telescopes, can be hard to measure and
then remove. In this paper we study the possibility of using a low frequency
telescope to aid in such correction for the Parkes Pulsar Timing Array (PPTA)
and also discuss whether the ultra-wide-bandwidth receiver for the FAST
telescope is sufficient to model the solar wind variations. Our key result is
that a single wide-bandwidth receiver can be used to model and remove the
effect of the solar wind. However, for pulsars that pass close to the Sun such
as PSR J1022+1022, the solar wind is so variable that observations at two
telescopes separated by a day are insufficient to correct the solar wind
effect.
