  Results of phase formation, resistivity (r), and thermo-electric power (S),
are reported on Y1-xCaxBa2Cu2.7Co0.3O7 compounds with x = 0.1 and 0.2. Pristine
compound i.e. without Co or Ca substitution crystallizes in orthorhombic
structure with space group P/mmm. Cu-site Co substituted compound i.e.
YBa2Cu2.7Co0.3O7 is tetragonal. With simultaneous doping of Ca at Y site in Co
substituted compound i.e. Y1-xCaxBa2Cu2.7Co0.3O7 the tetragonal nature still
remains. r(T) measurements showed superconducting transition temperature (Tc)
to decrease from 90K (YBa2Cu3O7) to 33 K for YBa2Cu2.7Co0.3O7 which with
further Ca substitution increases from 33K to 53K (Y0.9 Ca0.1Ba2Cu2.7Co0.3O7)
and 67 K for Y0.8 Ca0.2Ba2Cu2.7Co0.3O7. Tc decreases first with Cu-site Co
substitution by hole-filling and later recovers by simultaneous hole creation
by Y site Ca substitution. Room temperature thermoelectric power S(300 K),
which is an indirect measure of mobile carriers shows the decrease of carriers
with Co doping and creation by Ca substitution. Our results demonstrate the
hole filling by Co substitution is compensated by simultaneous Ca substitution.
