Does a ferrite bead (ring) work the same as an LC filter? Or do I need the capacitor as well...
I'd like to run my VTX off my flight battery (as we all do) but rather then use a LC filter, just use a ferrite bead.. (I am not using a filtered PDB, it's on a fixed wing)

Technically, a ferrite ring IS an inductor... which is the L (inductance) in a LC filter. So - no.

The inductance filter relies on how many winds the wire is wrapped around the ring.

But also, sorta kinda. Coz an inductance in series is kinda like a capacitance in parallel. An LC filter is both (L = inductance, C = capacitance), so more efficient.