Doubt about Suunto 9 Baro altimeter/barometer calibration

[A Former User]

Near my home I have a aiport. They report the weather conditions each one hour including altitude (fixed), pressure, etc. The report from today says: 1017 hPa and 6 meters (fixed).
I know that my home altitude is around 38 meters of elevation, that need result is similar pressure measurement, but when I set 38 meters as altitude reference on my Suunto 9 Baro the watch pressure change to 1021 hPa ¿?
I can expect a lower pressure value (1013-1014), but higher is not logic…
Any idea?

[Prenj]

I’m having crazy fluctuations of pressure inside my flat, but outside my ambit3 peak is very accurate. You are checking air pressure from inside your home right? And both of those numbers are sea level pressure?

[A Former User]

Thanks @Emir-Karisik
I have made reviews inside and outside, but it is a very good point that marks me about the interiors. I will check it again in detail and on the outside and recalibrating everything.

[sartoric]

@flypg
There should be a note somewhere in the manual saying that all the calibrations should be done outside, possibly in open fields

[A Former User]

@Emir-Karisik said in Doubt about Suunto 9 Baro altimeter/barometer calibration:

I’m having crazy fluctuations of pressure inside my flat, but outside my ambit3 peak is very accurate. You are checking air pressure from inside your home right? And both of those numbers are sea level pressure?

Test done @Emir-Karisik, same experience at outdoors with same results than in indoors with the with the auto-adjust altitude option
Yes, my previous Ambit 3 Peak was very precise in all situations. Never had a problem. Now with Suunto 9 Baro I can´t say the same

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

@flypg
There should be a note somewhere in the manual saying that all the calibrations should be done outside, possibly in open fields

Thanks @sartoric, I can´t found this on the manual when I readed, but even this is not the problem.

To be clear: today I done the auto-adjust at outside. The altitude that I get is really good, around that I know that is the altitude of this place, 35-40mts, and Suunto 9 Baro shows 35, OK with this. When I check the barometer screen of my Suunto 9 Baro showing: 1012 hPa. Pressure today around my area is 1005 to 1008, depending the zone. When I check this on my very cheap Decathlon weather station of 10 € show: 1005 hPa ¿! ?

How this cheap weather station can be more precise and not need re-calibrations?

BTW, my mobile sensor show: 1008 hPa…
Now again, I manually test the altitude reference by 39 mts, to check if this is a altitude problem, Suunto 9 Baro change the pressure that display to: 1013 hPa… ¿ ? With higher altitude the pressure need decrease, not increase. What is wrong?

[Prenj]

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

Now again, I manually test the altitude reference by 39 mts, to check if this is a altitude problem, Suunto 9 Baro change the pressure that display to: 1013 hPa… ¿ ? With higher altitude the pressure need decrease, not increase. What is wrong?

Manually increasing altitude by 4 meters (from 35 to 39) should not make a significant difference in sea level pressure. as it’s approximately only 0,5 hPa difference I think.

Are “baro holes” clean? Maybe you should try soaking your watch in a water for some time, just to rule that out.

[sartoric]

@flypg

Thanks @sartoric, I can´t found this on the manual when I readed, but even this is not the problem.

That’s why I said “should”

Check if the sensor is clean.
You can drop an email to support, maybe it’s a defective altimeter.

[A Former User]

@Emir-Karisik said in Doubt about Suunto 9 Baro altimeter/barometer calibration:

Manually increasing altitude by 4 meters (from 35 to 39) should not make a significant difference in sea level pressure. as it’s approximately only 0,5 hPa difference I think.
Are “baro holes” clean? Maybe you should try soaking your watch in a water for some time, just to rule that out.

Thanks, exactly, and be a reduction on the pressure, I believe.
No, this is a almost new device, no dirt or obstructions on the sensor. Tested also in other equal device.

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

That’s why I said “should”

Check if the sensor is clean.
You can drop an email to support, maybe it’s a defective altimeter.

Thanks, but I think that is not the problem. Sensor works well. I tested on two Suunto 9 Baro, also test mine walking on the stairs and sensor respond very well to the altitude change and showing correct data.

[surfboomerang]

I just did a test with my Suunto 9 Baro.
Calibrated at my altitude I get a reading of 1012hPa. Weather stations around me report 1010.7 - 1011 hPa.

[A Former User]

Update: My bad…

Doing testing and checks I see that I have, by default, on my SA the Altitude Source as: GPS. After I changed to Barometer and set the altitude reference the readings are very close to the reality

The only annoying is that I get different altitude value for the same point. For example: I set one specific point in 37 meters and tomorrow the exactly same point is 39, yesterday was 35, minimal differences, but differences.

This was very clearer previously on MC than in SA. Also because I could select the altimeter profile for each activity individually, very useful.

Thanks to everyone

[mario_b]

@flypg thanks for the link. if the alti baro watch profile is set to Baro. it should not change in elevation. but if you are doing sports meanwhile, the altitude will get changed by fused-alti (combi of gps value to pressure value). so that could be.
if the watch mode profile is set to auto and the pressure changes more then 0,5 hPa in 3 minutes or change in altitude for 5 meters it switches to alti mode until the pressure change is less then 0,5 hPa (or 5 meters) in 12 minutes.

[A Former User]

@mario_b You´re welcome. Yes, but now on my SA I not have anymore “Auto”, and also I not have anymore the possibility of assign a custom altitude profile to each Sport Mode
I miss MC… ajajajajjaa
Or I´m wrong?

[mario_b]

@flypg ahhh ok. i did not know that. i thought, whats on an “old” ambit, is same on an S9. sorry for that.

[mario_b]

@flypg on the manual it is written, that you can change to profile. maybe you can that in the watch without SA. like on the ambit3?

[A Former User]

Thanks! I not sure, but I believe that info from the manual are from old fw…

https://www.suunto.com/en-us/Support/Product-support/suunto_9/suunto_9/valid-for-barometer-version-only/outdoor-insight/

"AUTOMATIC ALTI-BARO PROFILE
Weather and altitude changes both cause a change in air pressure. To handle this, Suunto 9 automatically switches between interpreting changes in air pressure as altitude or weather changes based on your movement.

If your watch senses vertical movement, it switches to measuring altitude. When you are viewing the altitude graph, it is updated with a maximum delay of 10 seconds.

If you are at a constant altitude (less than 5 meters of vertical movement within 12 minutes), your watch interprets air pressure changes as weather changes and adjusts the barometer graph accordingly.

NOTE:
Sport modes have their own alti-baro profile setting. You can change this setting in our online account. The options are automatic, barometer only, or altimeter only."

[dombo]

@flypg I would say that watch is displaying sea level pressure and you are expecting real pressure. I have spartan and by manually increasing elevation also sea level presure is increased.

[mario_b]

i was confused before too. i think that the S9 also like the Ambit3 is not showing ambient pressure, but showing sea level pressure calculated with QNH. that calculates the from the ambient pressure and Altitude the sea level pressure without taking care of the temperature. the temperature is always calculated with 15° celsius. like METAR (METeorological Aerodrome Report) so for all the airplanes. local weather stations taking care of the surrounding temperature which gives you completly different values. search for your nearest Airport and METAR in google. for example METAR vienna and stay on the same elevation. you should get a quite accurate reading.
using QNH calculations gives you a great way traveling to a destination and set your watch to a pressure anywhere in the world, if you took that QNH value for getting nearly accurate altitude values.

[A Former User]

@dombo Yes, exactly. Later I noted this thanks to the Suunto Support. Thanks.
@mario_b Exactly, METAR is a great reference around the world and with useful information.

I pasted here the explanation/information in case that be useful for some other.

The watch shows:

1. altitude
2. sea level pressure

It will not show the absolute pressure. These values are interdependent - when you set one, the other one is changed so to be compatible with the absolute pressure the watch is measuring.

An example of this is set altitude to 0, you would see a sea level pressure equal to the absolute pressure - 1016 hPA. Setting altitude to 38 meters, the watch would know that absolute air pressure is 1016 hPA and infer that sea level pressure is higher - 1021 hPA.

Absolute air pressure is measured constantly (though not displayed): Absolute air pressure + altitude reference = Sea level air pressure

Absolute air pressure + sea level air pressure reference = Altitude

Changes in local weather conditions will affect altitude readings. If local weather changes often, it is advisable to reset the current altitude reference value frequently, preferably before starting your journey when the reference values are available.

[Mff73]

Hey guys, nice discussions, but hope you are not confusing SA setting for Altitude source, and watch ?
The only settings currently in SA, is to choose if your smarphone will determine altitude with GPS or Baro, if you intend to record an activity with SA and your smartphone (not your watch).
The settings for watch activities altitude source are still not changeable in SA, still only in MC for now.
Does it make senses ?

[DavorP]

@Mff73 Can you access altitude source settings for Spartan Ultra. This is screenshot of my settings in SA 4.2.4. (SSU)