GPSrChive Discussion Forum

When a 66st is running in Expedition Mode (EM), has anyone else found pronounced positive/negative elevation spikes shown on the elevation plot when the GPX track is viewed in Base Camp or GPS Visualizer?

From my experiments, these spikes are generated every time the device is "woken-up" from EM.

The spikes are corrupting the cumulative altitude figures grossly inflating both ascent and descent figures. The distance walked figures seem to be okay.

Also has anyone found any other issues with EM?

What are the Firmware and GPS Software versions of your GPSMAP 66?

GPS Software update (v2.60) was released two days ago to improve Expedition Mode reliability.

GPS Software version is 2.50
Software is 2.80

I have now loaded firmware update 2.60 and will see if things have improved on my next outing.

We look forward to hearing about your results!

I think this is the same problem I reported earlier on the trip odometer in expedition mode. I also found this sometimes affected the ascent figures it reported (10km ascent on a 2 hour walk on the flat).

I've paid more attention to the distance rather than ascent. I've also found that the error is mainly (though not exclusively) on wake up from expedition mode. I can zero the odometer, put in expedition mode wait five seconds wake it up and my odometer reads 9825km. If I do it again it's another 9825km added. Doesn't always do it. I went a couple of days with good behavior but it's normally bad. The amount added is always the same though appears position dependent. At home, it is always 9825km at work it is 9807km. I'd hoped to find they represented distances from a couple of common points but they don't seem to (though I'd likely need a reading from a more distant location).

I'm surprised you're he first person who seems to get something similar. If you use expedition mode you can't miss the problem. For the record, it does not appear related to settings, if I reset my unit to default settings it still happens.

I've reported it to Garmin.

Garmin Express doesn't show the update for me. Maybe because I'm on a Mac.

rogerm wrote: ↑Sat May 04, 2019 4:28 pm I think this is the same problem I reported earlier on the trip odometer in expedition mode. I also found this sometimes affected the ascent figures it reported (10km ascent on a 2 hour walk on the flat).

I've paid more attention to the distance rather than ascent. I've also found that the error is mainly (though not exclusively) on wake up from expedition mode. I can zero the odometer, put in expedition mode wait five seconds wake it up and my odometer reads 9825km. If I do it again it's another 9825km added. Doesn't always do it. I went a couple of days with good behavior but it's normally bad. The amount added is always the same though appears position dependent. At home, it is always 9825km at work it is 9807km. I'd hoped to find they represented distances from a couple of common points but they don't seem to (though I'd likely need a reading from a more distant location).

I'm surprised you're he first person who seems to get something similar. If you use expedition mode you can't miss the problem. For the record, it does not appear related to settings, if I reset my unit to default settings it still happens.

I've reported it to Garmin.

There was an issue with the GPS chip intermittently not waking up properly when the unit woke to take a sample, or so I heard. The latest GPS Software (not device firmware) is intended to resolve this issue.

RubbrDug wrote: ↑Sat May 04, 2019 5:01 pm Garmin Express doesn't show the update for me. Maybe because I'm on a Mac.

Can you try WebUpdater?

I have just had one brief outing having installed GPS software 2.60. Unfortunately, this update has not altered the generation of false elevation spikes every time the device is "woken-up" from EM. On this short walk the cumulative elevation is given as Ascent: 289m Descent 772m. The actual figures should be closer to Ascent: 100m Descent 150m. I have reported this to Garmin.

Anyone else want to try this and report back:

1. Enable EM in Auto mode and check you have a satellite fix.
2. Delete the current activity and reset the trip computer.
3. Go for a hike.
4. Walk for a reasonable distance eg 1 mile/1 km. You need to walk a reasonable distance so a smooth elevation plot is generated so you can contrast the spike artifacts.
5. Stand still and wake the device up. Mark a waypoint here and allow the device to return to EM automatically.
6. Repeat 4 & 5 a few times until your hike is finished.
7. Save track and upload to BaseCamp or GPS Visualizer to examine the cumulative elevation summaries and the plot.

@rogerm
I have compared the 66st with my old 62s and with a friend's 66st on several walks now. I have not seen any issues with the distance recorded in EM, just the consistent production of elevation artifacts every single time the device is "woken-up" from EM. Both the 66st devices show this issue.

Thank you Spiney, I also have made certain the Garmin Software Engineers see your post!