FM stands for Fan Marker. The frequency is 75MHz, true for all such markers.
The ident is modulated on a 3000Hz tone.

"S Herman" wrote in message
...
The LOC-D approach for SAN DIEGO/GILLESPIE FIELD (SEE) shows different
minimums for "GRIGG FM". There is an ident code shown for GRIGG, but
no frequency. Is the dot-dash-dot ident just the generic MM ident? I
can't find "GRIGG" listed as an airspace fix at airnav.com. Are the
higher minimums to be used for an approach in an aircraft without an
operating audible marker annunciation? What does "FM" stand for?
Airnav shows GRIGG as a Middle Marker. Thanks.