[amsat-bb] Loss Between Right and Left Circular

About 10 years ago got interested in sat radio and bought a Left Circular Quadrifilar Helix Antenna which got good review in QST. Didnt use it and now retired and trying to get on sat. Evidently most ham sats are right circular and depending on what I read. there is a 30db OR 3db loss going from one circular polarization to another. Which is it?

Thanks Roger N3RC