I think it would increase the coil losses, compared to a higher inductance coil of same Q, without the capacitor.
Pcoil = I*U/Q
At same radiated power, you'll have the same voltage but higher coil current due to the extra capacitor.
Hi Marcus,
indeed, parallel capacitor will increase the coil current, but on the other hand you will get resonance with a smaller inductance. I haven't done any calculation on the case (yet), but probably both effects (larger current vs smaller coil) will more or
less compensate each other.
73, Rik ON7YD - OR7T