Elevation always increasing

I would like to ask if some of you have the same problems I've been experiencing since a few months.

I already hinted to this in some other posts but I would like to make a more structured thread here.

Basically what I'm experiencing (Fenix 6X Pro) since I would say firmware ~12, is that during whatever activity the elevation measured by the instrument always rises, to the point that, going in a loop, I end up several tens of meters higher.

This happens always, be it walking, cycling, running: even just doing flights of stairs.

For instance, at my workplace I use to go several times downstairs (to the lab) and then upstairs (to the office), and I'm consistently getting something like this (these are taken during different days:

Thinking it may be a clogged barometer port, I took the suggestion by C.sco and soaked the watch in a warm water bath with soap, but it did nothing.

What do you think can be the problem? Software or hardware issue?

0 5693709 over 4 years ago

what happens if you go into the altimeter mode and remain at the same elevation? Does the reported altitude slowly increase?

Or are you saying that even if you go to a lower elevation, the altimeter reading goes higher when it should go lower?

Do you have any auto-calibration option enabled, if so, disable it and see if anything changes.

0 C.sco over 4 years ago in reply to 5693709

5693709 said:
Do you have any auto-calibration option enabled, if so, disable it and see if anything changes.

That's what I suspect. Auto-calibration (in "continuous" mode) will sometimes cause weird elevation shifts over time like this. It uses the DEM (earth contour) file in the watch, and gradually adjusts your elevation reading either up or down until it matches what it thinks is your elevation (according to the DEM file & your GPS location), which may not be correct, especially when you are not at ground level (ie, in a building, using stairs). If the DEM file isn't precisely accurate, then it results in an inaccurate drift upward or downward during the activity.

The solution is to not use "continuous" auto-calibration during activity. I use "at start of activity" instead, which works great for me. It calibrates the altimeter to the DEM file once, at the start of the activity, and then uses ONLY the barometer thereafter.

0 gspinoza over 4 years ago in reply to C.sco

Autocalibration has always been off for me.

And the solution cannot be "not to use continuous autocalibration during activity" because my issue happens out of activities. I don't use any activtity just walking up and down stairs during a normal day of work..

0 gspinoza over 4 years ago in reply to 5693709

5693709 said:
Or are you saying that even if you go to a lower elevation, the altimeter reading goes higher when it should go lower?

No. What I'm saying is that i go down a flight of stairs and the altimeter goes down, say, 2 m. Then I go up the same flights, and the altimeter goes up 4 m. This over and over, consistently, so at the beginning of the day I find myself at 245 m, while at the end it says 260 or something like that. And, as I said, this is consistent: every day, every time I go up and down stairs.

Not to mention the same problem during activities (running, walking, cycling): it seems that the barometer does not read in the same way a rise and a descent of the same value in air pressure.

0 5693709 over 4 years ago in reply to gspinoza

that does sound odd because if it always happens the same way then its not likely caused by barometric pressure changes due to weather. those would be more random up or down, not always up.

So are you saying that if you went up and down the same flight of stairs, let's say 20 times as fast as you could walk, that the altimeter reading would be 40m higher at the end of the test, and there's no way it could be due to weather changes. If so, then that's very odd.

0 gspinoza over 4 years ago in reply to 5693709

5693709 said:
So are you saying that if you went up and down the same flight of stairs, let's say 20 times as fast as you could walk, that the altimeter reading would be 40m higher at the end of the test

Well, as a matter of fact I don't know, as I don't want to go up and down 20 times for no reason, given that I have backache these days.

What I can tell you is that today I've gone up and down that flight of stairs maybe 3 or 4 times, and I'm already 8 m higher.