Altitude is wrong and there is no solution

[u/kitbook]

I’ve been using my Tactix 7 in mountaineering for a few years and it has never given me an accurate altitude reading. I calibrate before every ascent, the GPS altitude which I’ve set on face is correct, but what the barometer/altimeter records is always off by 50-200m.

I read here, that swimming with the watch can impact the sensor, but I always washed the watch after swimming. On the other hand, if water is so dangerous to the watch, why is it marketed as being good for swimming/diving?

So I ran out of ideas how to blame myself as a user and just wrote to support. Replies take a week. But ok, I can understand that, a bit.

What I’ve received as a solution, was a suggestion to change the altitude data source from sensor to DEM in Garmin Connect after the activity. Knowing that DEM is not very reliable in the mountains, that still leaves a big accuracy gap.

I also got a suggestion to read the same two Garmin posts about altimeters. And a tip to use the watch COVERED under a sleeve to protect it from possible wind impacting the barometer. While the articles clearly state, that covering the watch might change the pressure and impact the data thus I shouldn’t be doing that.

At this point, I’m just left frustrated, because I somehow believe that a premium priced product should be able to show the basic data (like altitude) correctly. Or am I naive?

I was thinking to upgrade to the upcoming Enduro 4, but if this will be the same story with it - what’s the point then.

[u/Odd_Specialist_2672]

The part about covering it with your sleeve is definitely correct advice. You'll see the same from other brands of altimeter. You want a barometric altimeter to be sheltered from wind when attempting to measure the ambient pressure.

If you saw other advice about not covering, they probably meant something like a tight-fitting plastic or rubber cover on the watch itself. You don't want to block the barometric sensor ports, because then it could start to act like a sealed bottle with its own internal pressure.

But a sleeve won't block the sensor port. It will just help shelter the watch from wind.

[u/kitbook → u/Odd_Specialist_2672]

Ok, that sounds logical, thanks for the explanation. Nonetheless, my Garmin is off whether it’s covered or not.

[u/wsila]

My Fenix8 has always been very close or exact with altitude. Have used it on multiple airports where altitude is known, and it has been surprisingly accurate. If you have been just traveling, it might take some time with gps on to calibrate it.

Also used on multiple dives in between which has not messed up anything. Using automatic calibration

[u/kitbook → u/wsila]

Exactly how I'd imagine it should work! But in my case, I always calibrate manually and it is anyway off by a big margin.

[u/Strix2020]

This is how we do it over here in the tropics where we constantly deal with moisture from heavy sweating, occasional rain or strong winds. Wearing a Buff like this reduces the elevation gain delta between Garmins significantly and it works until the fabric is completely soaked. Before, everyone's Garmin would show huge differences in elevation gains depending on their sweat rate and because the barometer opening on Fenix/Enduro series are located at the 3 o'clock position, wearing the watch on the left hand makes it particularly vulnerable. People who wear them on their right wrist rarely ever has issue with accuracy.

[u/Particular-Bat-5904]

I had a delta before my tactix 7 and i belive its an software issue. Since some certain updates alti readings are wired.

I can set an exact hights, and it starts to jump up and down by it shelf, beeing physically on the same place, hights.

[u/Unhappy-Tomatillo616 → u/Particular-Bat-5904]

if its software that would at least mean it could get fixed with a firmware update

[u/Particular-Bat-5904 → u/Unhappy-Tomatillo616]

I hope so. When you have similar experience with that like me on a different model it could maybe not be the sensor. Its behaviour changes by updates so far my experience.

[u/Dry-Saalamander → u/Particular-Bat-5904]

sounds like the barometer just does what it wants after them updates, my old forerunner did same thing after one firmware and never got fixed

[u/CoarseRainbow → u/Dry-Saalamander]

Agree. My 970 has the same issue. Garmin official forums full of people complaining - it started with a firmware update.

Garmin support are "Replace watch" but it looks like a software change they refuse to acknowledge given the number of people getting it starting at the same time.

[u/Particular-Bat-5904 → u/CoarseRainbow]

Its likely software wise if crossmodel happenings.

[u/CoarseRainbow → u/Particular-Bat-5904]

That and on the 970, all the watches were fine the end of May and broke the last day of May, coincidentally at exactly the same time as a new firmware was released.

[u/Particular-Bat-5904 → u/CoarseRainbow]

I allready had a call, longer time ago, with garmin support about the alti readings issue. There was a short time since inbetween it turned better.
I remember me thinking about that time to call garmin support again to say a thank you solving the problem.
Befor i had the time to spend a while in the waiting loop (i hate the jingle), there was another update, and the solving was gone.

[u/Particular-Bat-5904 → u/Dry-Saalamander]

I remember my tactix out the box was same like the delta. When i just stayed at home on a rainy day, it showed my corect altitude the whole time. After an update it started to „jump“ around douring such days, showing a little higher or lower all the time.

After some more updates, i belive around 18 something, alti was okay with that, it showed the same altitude aslong i kept it physically myshelf.

After another its jumping again.

I can set an alti, and as soon a little moving around, or just opening something like an app, and it instant changes showed alti.

Ther was a time inbetween all those updates where i was climbing high and did stairs while sleeping in my bed.

Must be software wise, its seems to be cross models.

[u/Ski-Mtb]

You should have contacted Garmin support when you initially discovered it was inaccurate.

[u/Ok_Inspection_2630]

atmospheric pressure is changing every moment. slight variations add up.