1) The SiRFDemo User Guide indicates that these settings are saved in battery-backed SRAM. How long will these settings survive after the EM408 is powered off? I can't find any documentation and USGlobalSat tech support said the settings are “terminated once power is removed from the device.” The settings aren’t terminated but I’d like to know how long they survive.
2) With the EM408 sitting indoors on my desk I have watched the GGA sentence output and calculated position variations over 120 feet without moving the EM408. Is this normal when the number of satellites acquired varies between 3 and 7? Would an active GPS antenna reduce the position variations? Thanks.