In order to study the Blazhko effect, we characterise the modulation of the RR Lyrae star SS Cancri,
which has been reported to have the shortest modulation Blazhko period. B, V and R band data have been acquired.
The pulsation period is 0.36731 +- 0.00004 d. No significant change in the period over the last 80 years is observed.
We measure a periodic variation in the light curve maxima, which has a period of 5.313 +- 0.018 d and an amplitude
of 0.016 +- 0.003 mag. The best model that describes the Blazhko effect is the resonance coupling between a low
and a high order radial mode
