Does anyone have useful thoughts on why a track my 66i recorded a track today, 24 Jun 2022, with only one point during a period lasting longer than an hour?
The 66i Recording settings were Record Method Auto, Interval Normal, Auto Pause off, Auto Start off, Activity Type Hiking. The device was recently updated to Software ver. 9.20 and GPS version 2.90.
Before starting the hike, I activated satellite tracking at one-hour intervals, which automatically started recording, put the 66i into Expedition Mode, located it upright in the back of my pack so that only one thin layer of nylon was between it and the rest of the universe. Then I began hiking at 11:46 local time. I didn't touch it or take off my pack until I returned to my starting point at 15:23 local, about 3.5 hours later. At that point I stopped the Iridium tracking, which also stopped the recording. And I turned off the device. When I looked at the track on BaseCamp, the 66i had recorded the track at My GPX File (a link that will expire after 8/31/22).
Compared to past tracks (not in Expedition Mode), the track's planar record is reasonably accurate until 13:36. As expected from Garmin documentation, the Expedition Mode track was less accurate than the non-Expedition Mode tracks on the same trail, but track recorded today in Expedition Mode was still fairly accurate up until the point where it wasn't. At 13:36, it essentially stopped recording. It resumed recording at 14:40 and continued recording a reasonably well until I finished. Between 13:36 and 14:40, it recorded one track point at 13:47. That point was an a fairly accurate planar position.
There were no events or local conditions that would account for hour-long lapse in recording. In fact, the first part of the hike where the device was recording an appropriate track was at the bottom of a narrow canyon with almost vertical walls. So if it were to fail to record an accurate track, you would expect it to fail there. Moreover, the point at which the failure begins is seconds after the highest point of the hike where the view of the sky was best.
My 66i has never recorded a remotely accurate spatial track when in Expedition Mode, although it records plausible spatial tracks when not in Expedition. I've tested one other 66i that was also unable to record a reasonable spatial track in Expedition Mode. After every few updates I recheck again to make sure this undocumented defect still exists. I've asked Garmin more than once in past years to either document or fix this defect in Expedition Mode. As you can see from the elevations in this track, the spatial track is absurdly inaccurate, as usual. Today, the Altimeter was set to Auto Calibration Once.
I anticipate someone will be tempted to post a reply saying he never uses Expedition Mode and I can solve the problem by not using Expedition Mode. However, Expedition Mode is a tremendous feature for applications like one I'll need in a few weeks. Today, the battery level went from 99 percent at the start of the hike to 98 percent 3.5 hours later, during which time it was sending up track points to the satellite. Several times, I've gone more than a week on one full charge with the 66i in Expedition mode sending hourly updates through most of the daylight hours and sending and receiving dozens of messages. So it's a great feature. If only it would work as advertised.
I also sent an InReach message before starting today's hike and another when I finished. I received an InReach message while I was hiking, though I didn't see it until much later. As I said the 66i remained untouched during the hike. It may not be unrelated but the received message I referred to was sent from a smartphone at 13:03 and was "received" (I think that means by the 66i) at 13:51, which was 13 minutes after the failure started. So the 66i may have been trying to receive the message when the failure began at 13:37.
In case it is relevant, there is a loose correlation between the track points sent to the Iridium network and the failure points in the recorded track. The first track point after the initial track point at the trailhead was recorded at 12:46 at a position where it might have been difficult for it to transmit to an Iridium satellite. As I said, the first failure in the recorded track began 10 minutes later at 13:37. Then the single point that was recorded in the track during the hour+ lapse in recording was recorded at 13:47, which within a minute of when the next track point for the Iridium network was recorded. As I said before, the device began recording the track again at 14:40. The next track point sent to Iridium was recorded six minutes later at 12:46.
