Hi i have a navman f20. i can not get a gps signal, everything seems to work ok. when you put a post code in it searches for gps signal but does not find it, or if you just switch on it searches but does not find it. the last time i went out everything was ok, i returned home and switched off. when i put it back on i can't get no signal. even standing in the garden with it is the same. i have tried resetting the gps and also put it back to factory setting. i have updated the system from navman, but still can't get gps. can you please advise me.
many thanks eric

GPS - Navman - F20 GPS Receiver