i have an e-trex legend, & a magellan 315. decided to hook up the magellan up to the kenwood (aprs) radio - for a few reasons. it doesn't have a built in map, it's bigger so i actually don't want to carry it around - but it has a much better antenna and better reception. it's perfect for a plain old gps receiver. although larger than say a gps-mouse unit, i have it tucked away in the corner on the dash. i'll save the e-trex for walking around, plus i don't need to buy anything new. this does require i leave the unit powered up (usnig 12volt adapter), but it shouldn't drain the battery.
while testing things out, i noticed when i lost satellite reception with the e-trex, the kenwood would start to **beep**. however with the magellan, it didn't...
as far as i can tell (reading the serial data from both), the e-trex keeps sending packet data when there is no reception.
in theory that would be fine - various NMEA sentences include validity of the location data, and you can still get other details like current time, or see how many satellite its tracking (or not). so it keeps sending data.
they both take a while to determine they've lost reception. the magellan keeps sending data for a while (with less data) - but then it just stops.
therein lies the difference. where the kenwood starts to complain about the data it's receiving from the e-trex, the magellan isn't sending data!
in this circumstance, the later is much preferable. although i find the e-trex screen notification about losing satellite reception distracting, having a device beep at you in annoying. especially since i don't really care i've lost reception.
if kenwood included a setting for that, it also wouldn't be a problem really.
so the magellan really shines here. it tracks better and won't raise a fuss - it just updates the kenwood when it gets a location again.