One of the petty irritations of this life is radio science reporters who insist on making sure we know they are a doctor. I suspect they think it gives them credibility. More often it signals they are pompous. The only time it would give them credibility would be when they are discussing the narrow specialist topic they gained their PhD in. The rest of time, their PhD doctorate counts for little. The only exception I would make would be for medical doctors. That's because they train in general medicine before specialising and therefore have more knowledge than the average reporter off the street.