Altitude Issues

As this discussion is titled altitude, I can confirm there is such problem with the MK1. It's seems altitude changes are confusing the software, the faster and bigger the changes, the larger the confusion. There is a discussion about the skiing activity here, in short, this problem makes the MK1 almost useless for skiing. GarminHeath tried to help and finally requested log files from some users. However, the problem has not been solved so far. For example, I went for a hike this Sunday, on the valley ground the altitude was correct (480m), I drove up to a mountain parking lot (@1'240m) and started the activity under perfect clear sky with spot-on GPS accuracy, however the Altitude measured by the MK1 was 1'753m what is a whopping +513m off ! This +500m offset remained for 12 hours or so, only the next day the MK1 did a correct auto-calibration and the altitude was back to reality. It's kind of frustrating to enter the 3^rd skiing season with the MK1 soon, knowing after almost 2 years on the market this bug has not been fixed by Garmin. I understand they have to put their focus on new and higher volume products, but I think it's not ok they ignore such major bug on a lower volume, higher price product like the MK1. It's not about bashing Garmin or their products, I like their Sportswatches. But they promote the MK1 for Skiing, Hiking, etc, so as a customer I can expect this to be working and if not we should inform Garmin about it and request them to fix it.

P.S. I don't see this problem on my Edge1030 and also did not on my old Fenix3HR, both units deliver spot-on altitude information.

hi, and thanks for your comments.  Thanks for spotting that I also, quite deliberately, titled the thread appropriately.

My understanding is that the architecture of all the wearables from Garmin is the same - I am unaware of any change to the sensor/sortware/firmware across the range of fenix, marq, descent etc - I have asked Garmin directly many times for a technical explanation and one has never been provided.

I also asked here - Mr Nobody claims to have knowledge but is unwilling to share.

There seems to be a corporate denial that there is anything wrong with the architecture or the sensors, however there do seem to be many hundreds of users of all devices reporting the exact same issue - perhaps Garmin will eventually take note, or perhaps they are relying on sheer volume of sales to 'hide' the data such that it doesn't represent a significant enough percentage to trigger any kind of response.

Either way, I am unimpressed and would still be very wary of spending 1K on a new dive watch - that's a lot of money for a depth gauge!

For clarity, my original fenix - the 3 - bought when they first came out, worked perfectly for 4 years, then suddenly the sensor started to fail, despite auto-calibrate and regular use with gps tracking on activities, the device shows a c 10m loss every day when essentially stationary and, like you have reported, significant losses/gains when actually used at altitude.

I had it showing me I was at -47m when I was trekking at 220m

Goose said:

nteresting link - I take it you've actually read it?  An out of court settlement which only applies in the USA and only if your device was bought through Aqua Lung as the distributor?  Interesting that Suunto deny publicly any issues with the products, also very interesting that this claim has only been brought as a class-action in the USA.  I would have thought any real issues would have brought in the USA equivalent of health and safety, advertising standards and if true, would have led to a world-wide recall.  Perhaps I'm missing something, but the article, and judgement makes no comment on the veracity of the claim, only that if you purchased one of the products listed you are entitled to an assessment and possible replacement if it is found to be defective.

That's just one article of many that discusses the problem.  The point is this is a brand that "have a depth of knowledge and history of performance under the water" that had a known major problem with their pressure sensors and tried to hide it.  This is actually a safety problem.  A company doesn't settles for $50M unless they have something to hide.  

So the issues is: Is the incorrect Altitude affecting diving at the altitude? Basically, if the altitude is incorrectly measured by Garmin MK1, does it affect the diving calculations? Do we have a safety problem here!?

I googled "Altitude accuracy watches" and got some interesting hits.

This one was particularly interesting:
https://www.outdoorgearlab.com/topics/camping-and-hiking/best-altimeter-watch/buying-advice

There's a lot of information in there that talks about how the altimeters work, what affects them (such as weather, latitude, etc) and how often they need to be calibrated.

Here's another interesting like that compares various watches:
https://www.outdoorgearlab.com/topics/camping-and-hiking/best-altimeter-watch

MarcinB said:

So the issues is: Is the incorrect Altitude affecting diving at the altitude? Basically, if the altitude is incorrectly measured by Garmin MK1, does it affect the diving calculations? Do we have a safety problem here!?

I thought I already answered this.

The simple answer is NO.  No problem at all.  The worse that could happen is that the Mk1 might display the incorrect depth. The NDL and deco calculations are based on the relative pressure changes from the start of the dive to the end of the dive rather than the displayed depth.  Those pressure changes will be just as accurate at altitude as they would be at sea level.

Edit

I should add that if you are diving with tables at altitude and using the Mk1 in Gauge Mode, then definitely manually calibrate the altitude at the known elevation just before the dive as accurate depth information is necessary.

What starts worrying me after this discussion here is the question if a wrong altitude has an impact on the dive calculation. Above I have described a situation my MK1 was of +500m after a fast altitude change and only recalibrated to reality some 12-24h later. So what would have happened if I did a dive in this situation? Would the MK1 have assumed I am doing an altitude dive 500m above my real position? And what influence would this have to the dive calculation?

Maybe one of the dive pros here is ready to test this on a MK1 with a wrong altitude setting and compare is with a reference dive computer. If this should have an impact I think in minimum Garmin should let out a warning that altitude of the MK1 can be wrong and needs to be verified before each dive. If the Altitude does not have an impact on the diving calculation, I am relieved, but still have this known issue for mountain sports. This is still frustrating, but at least not dangerous to my health.

Edit: The Bühlmann ZHL-16C algorithm does include the elevation. Other dive computers have a manual setting for the elevation, typical in 3 levels 0-300m, 300-1500m and above 1500 and give a clear warning in the instructions that you MUST check the altitude before the dive and have this setting right. The MK1 does not provide this setting. Is it correct to assume it uses the altitude information for this ? If yes, an offset of 500m can very well make the difference if a dive is considered a sea level dive or an altitude dive. 

rolfsg said:

The Bühlmann ZHL-16C algorithm does include the elevation. Other dive computers have a manual setting for the elevation, typical in 3 levels 0-300m, 300-1500m and above 1500 and give a clear warning in the instructions that you MUST check the altitude before the dive and have this setting right. The MK1 does not provide this setting. Is it correct to assume it uses the altitude information for this ? If yes, an offset of 500m can very well make the difference if a dive is considered a sea level dive or an altitude dive. 

The Shearwater Perdix in OC Rec mode uses ambient atmospheric pressure. This can't be set and it measure it itself.  I can't imagine the sensor for ambient atmospheric pressure being more accurate than the Mk1.

In OC Tec mode you can override this to Sea Level for sea level dives but in auto mode it determines the pressure itself.

My understanding is that if you are at sea level but the Mk1 thinks you are at 500m it will actually be safer (shorter NDL, etc.) and so wouldn't be a safety problem. Ultimately, it should be using the change in pressure from the start to the dive and so may not make any difference at all.

Interestingly, I have never seen that much variance in elevation with my Mk1.  Mine is out by at most 50m at any time.

rolfsg said:

Maybe that's why other dive computer producers leave entering this parameter to the user, knowing about the challenge of accurate altitude measurement. But of course this is pure speculation.

As above, users can't enter their elevation/altitude with a Shearwater Perdix (also Bühlmann ZHL-16C).  In OC Rec mode, only Auto is possible where the Perdix determines the ambient pressure.  In OC Tec mode you can change from Auto to Sea level but even then if the pressure is lower than 965mb it reverts to auto. i.e. you cannot enter elevation.

Shearwater are the bees knees in dive computers.

How many people, other than James Bond, would go directly from skiing/mountaineering to diving?