Total posts : 45366
I’m pretty sure you’re actually using an iron powder rod, common mistake, made it myself before. Ferrite is usually used for filtering and Iron Powder for tuning, according to the Amidon tomes.
I have read that the trade off is that air core has higher Q but more wire and therefore more resistance
Slug tuned can have lower Q but far less wire, less resistance to an already tiny signal.
I have had far better luck with iron powder toroid and rod rod core wound inductors than with air cores. Others the opposite experience.