Doubt about Suunto 9 Baro altimeter/barometer calibration

[mario_b]

@TELE-HO yes suunto service is fantastic.
no it really didn’t.

on small hikes i do not record it, but wanna know the nearly correct elevation. and a guy from search and rescue (with an a3p) told me: if you look at the nearest weatherstations ambient pressure and compare that with your watch, you know about +/-10-15 meters if your elevation is correct, without the need of activating gps. and that works very well.

[johann.fuehrer]

@mario_b said in Doubt about Suunto 9 Baro altimeter/barometer calibration:

@johann-fuehrer just to be sure:

• you know the exact elevation you are when reading your watch pressure? and the altimeter is set correctly?

Definitely!

• you did the fridge test which @Dimitrios-Kanellopoulos mentioned above?

Yes, coming back to exact the same altitude. In my opinion it was very quick, some 5 minutes. But I’ll do it again if you like.

• you are not inside a building?

No.
I did check this also inside the office (open windows), so ambient pressure inside and outside should be equal, no aircondition and the behaviour is the same like outside.

[mario_b]

@johann-fuehrer so maybee it should be recalibrated. i would ask the support.

[johann.fuehrer]

@johann-fuehrer said in Doubt about Suunto 9 Baro altimeter/barometer calibration:

@mario_b said in Doubt about Suunto 9 Baro altimeter/barometer calibration:

@johann-fuehrer just to be sure:

• you know the exact elevation you are when reading your watch pressure? and the altimeter is set correctly?

Definitely!

• you did the fridge test which @Dimitrios-Kanellopoulos mentioned above?

Yes, coming back to exact the same altitude. In my opinion it was very quick, some 5 minutes. But I’ll do it again if you like.

• you are not inside a building?

No.
I did check this also inside the office (open windows), so ambient pressure inside and outside should be equal, no air condition and the behavior is the same like outside.

Finally, meetings are over: watch was 1 hour in the fridge @ 8 degrees Celsius:

10:00 before fridge, 1024 hPa, 30 C, @ 210 m
11:00 immediately after taking out the fridge, 1024 hPa, 8 C, @ 210m
11:15 another 15 mins later…, 1024 hPa, 25 C (still going up) @ 210m

LOWW & ZAMG still at 1020/1019.5

[Dimitrios Kanellopoulos]

@johann-fuehrer if not affected by temp your sensor is pretty well clean and no defect

[mario_b]

@johann-fuehrer are you at the “Umspannwerk Südost”? that’s the only point which is on 200m elevation. according to different maps, the rest of unterlaa is between 165 and 180m of elevation.

[johann.fuehrer]

@mario_b I had been, but now im at Hauptbahnhof/Belvedere which is (funny) also at 200m (Info from Geodatenviewer, wien.gv.at).But the pressure in different altitudes here in Vienna is not that big at the moment so that this would have an effect.

[mario_b]

@johann-fuehrer if the baro works, so altimeter is correct, meanwhile i would not mind, because i know over time it slightly drift anyway. but if you care, i would contact the support. the support is really great and helpfull.

[Fatih Kale]

Hi all,

Yesterday I ran on a track while raining so watch was covered by my jacket.

When I check altitude profile it’s veird. It shows that I went downhill but it’s not possible as I was at the same location turning around. Why could this strange values observed?

Here is altitude profile
link text

Here is the temperature graph
link text

[freeheeler]

@Fatih-Kale
I’ve seen a similar behavior with my Suunto Core some years ago.
When the sensor is covered or in contact with wet skin it seals off and or has a pumping effect.
I would expect that this wrong measurement is detected by fusedalti, but until today I still don’t understand how fusedalti works in detail and what it does over an entire activity or when for some reason the alti is completely off reality.

[sartoric]

@Fatih-Kale
Check if you also have some magnetic stuff (like magnetic jacket cuffs)

[Mff73]

@sartoric said in Doubt about Suunto 9 Baro altimeter/barometer calibration:

@Fatih-Kale
Check if you also have some magnetic stuff (like magnetic jacket cuffs)

For altitude issue? 🧐

[isazi]

Also if it was raining and there was a storm coming in, or any other air front, and you just came out of your place, the altimeter may be adapting to pressure change.

[sartoric]

@Mff73
mostly for gps (so fusedalti)

[Mff73]

@sartoric said in Doubt about Suunto 9 Baro altimeter/barometer calibration:

@Mff73
mostly for gps (so fusedalti)

I didn’t know about GPS issues with magnetic parts Compass OK, but GPS.

[sartoric]

@Mff73
For sure not the signal , but I won’t discard issues due to components (maybe not directly related to gps) or maybe something related to fusedtrack

In an old topic we discussed about issues with OHR reading due to magnetic interference … or maybe was gps … need to check it

EDIT :
Was fusedtrack (keep asking to calibrate) in that case, don’t you remember ?
https://forum.suunto.com/topic/1371/s9-2-4-14-calibrate-fusedtrack-interface-problem-suunto-case-01853829/100

[Brad_Olwin]

@Fatih-Kale If the sensor is covered altitude readings can be wrong or distorted. I have this happen when the sensor is covered by a buff as well.

[Fatih Kale]

Thanks all it was possibly due to sensor was covered.

I had another run last night, this time I strapped watch over the jacket and got correct readings.