FIRSTLY:

If light has no mass and is instead a reverbation of it's medium. Then
one could rotate wave reflectors (mirror simulation) in air or water
and record the sagnac effect on sound or water waves....the wave
reflectors (mirrors) disturb the medium thus possibly the ether.


SECONDLY:

If the ether is an energy field then it could resemble a field of
carrier waves.

Modulate a radio carrier wave to travel in both directions of rotating
reflectors (material from satellite dishes) as in a Sagnac model. Then
record if there's any phase latency between both modulations.

If the Sagnac has ZERO ***OR*** a similar effect to light then the
Sagnac experiment CANNOT validate the existance of an ether for it
cannot validate the existance of air, water or a carrier wave.