I have a handheld unit that I use on occasion at the coast. Lately it has a hard time locking on to satellites. I say lately but I really have not used it a bunch. I took it out today and it locked on after a minute then lost position. There were some oak trees around but nothing major to block a view of the sky. It was a partly cloudy day. I changed the batteries and tried again this evening and it did ok. The Lowrance website says expect 20 minutes to lock onto a satellite. This seems excessive to me. Are these units that temperamental? I tried using it in my vehicle last month and it would not pick up a satellite. Is this normal? Thanks in advance