Ok. I've found a solution for the loop():
if (fix.status==gps.fix::STATUS_NONE && fix.satellites==0) lcd.write (byte(0));
0 NF
0 t
1 t
2 t
3 t
4 t
4 F
5 F
Now, only when are 0 satellites can appear the symbol "NF". It works, but why STATUS_NONE is true with one or more satellites?
It still doesn't work in Ora e data.