Call'n Grey Fox....
Use Grey Fox Pup sounds
Keep behind red lens
Keep red light on at all times
Keep scan'n for eyes
Some folks say when call'n IN woods or brushy areas the light will cast a shadow and things won't appear natural to critters. You may be shook'n 'em.
This may not be the case because many a critter has be killed in the woods.
Many areas of the state, the best setup is the woods or on a log'n road or power line.
My guess why you had no response, the Greys are not there or weren't in hear'n distance or weren't interested.
Do you know Greys are there?
I do like to call at night, from a clearing or field, standing in the open, for the most part.
I scan the intended approach routes, staying behind my red lens.
Grey Fox are bringing $30-$33 at most fur sales.
Folks are hitting Greys hard this season and maybe your area has been called or trapped this late in the season.
Do some scout'n.