The sensitivity of the PPTA Data Release 1 data to monochromatic gravitational waves (Zhu et al. 2014), along with the expected gravitational wave strain amplitude of some published supermassive black hole binary candidates. The black curve represents the all-sky sensitivity and the red curve is for the most sensitive sky direction. Blue circles have assumed a mass ratio of 1 for candidates reported in Graham et al. (2015). References for other candidates are: OJ287 - Valtonen et al. (2008), PSO J334.2+01.4 - Liu et al. (2015) and 3C66B - Iguchi et al. (2010).