Last fall, W9SWR was on 75 m. one night and he had three D104 heads, one with an Astatic xtal element, one with the Astatic ceramic element and a third with a Kobitone xtal element. He did an ABC test swapping the heads on a G stand. the Astatic xtal element sounded great; the ceramic element almost as good but not quite. If he had not mentioned anything about it being ceramic, one might have not noticed anything. The Kobitone was comparatively abysmal, just awful. No where near the clean clear sound of the Astatics. The two or three of us on frequency told him to pull it out of the D104 head and throw it in the trash.