  We present results of a 2014-2018 campaign of radial velocity measurements of
$\delta$ Ceti. Combining our determination of pulsation period with historical
data we conclude that the most likely explanation of observed changes is the
presence of a secondary component with a minimum mass of $1.10 \pm 0.05
M_{\odot}$ on an orbit with a period of $169 \pm 6$ years. Consequently, we
revised the intrinsic, evolutionary period change rate to not larger than
$0.018 \pm 0.004$ s/century, which is significantly lower than previous
estimations and is consistent with evolutionary models of Neilson & Ignace
(2015). We did not find any significant multiperiodic frequencies in radial
velocity periodograms such as those reported by Aerts et al. (2006) in
photometric data from MOST satellite. Using interferometric angular size of
$\delta$ Ceti from JMMC Stellar Diameters Catalogue we determined several
physical parameters of the star with bolometric flux method. They turned out to
be consistent with most previous deteminations, confirming lower mass and
slower evolution of $\delta$ Ceti than obtained using different methods by
Aerts et al. (2006) and Neilson & Ignace (2015).
