16. A non-empirical rotation activity relation for RS Cvn binaries using radio luminosities. Gunn A.G., Irish Astronomical Journal, 1998, 25, 33. Compressed Postscript (76 kbytes) Compressed PDF (393 kbytes) ABSTRACT. An analysis of a comprehensive survey of radio luminosities for RS CVn binary systems is given. A comparison is made between the rotation-activity correlations found using the usual semi-empirical Rossby number and a Rossby number deduced from detailed convection zone models. The use of a non-empirically derived Rossby number does not significantly improve the rotation-activity correlation. Although there are some indications that the rotation-activity correlations are marginally better for theoretically derived convective parameters this study is limited by the size of the sample.