# Suunto Core Altimeter - accuracy test



## Ambor (Nov 28, 2007)

Hi guys, just wanted to share with you my first experience with altimeter on my Core.

1. Set the reference altitude on the watch.
According to foundation plans of my house and internet input (topomaps) I have figured out that my house location altitude is 180m. As I was standing when setting the reference in the watch, I set the altitude to 181m. Just for the record the whole day there was no change in barometer reading, very steady 1030hPa. So I was not expecting any influencing by the barometer. 


2. Setting the correct profile and measure.
After that I went for a walk to the top of the nearby hill, which was supposed to have an altitude of 215m (according to the same topomaps).
I switched to Altitude profile from the Time/Date view. The altitude jumped immediately to 182m. As I was climbing the hill slowly, I was watching how the altitude was changing. I was a bit surprised, as the visual height change could be some 1m, but the watch showed some 4m change. I thought it might be due to the changing angle of the slope and when I would reach the top, I would see. 
I have reached the top of the hill after some 30min of walk. The Core displayed 225m of altitude. Which was a difference of 10m to the reality. :think: 


3. Resetting the reference altitude again and measure again. 
Immediately I have changed the reference altitude to 215m and went down the hill.I have noticed the same trend of decline and measurement as before. It seemed to me a bit off the reality, but this time I thought that's the way the Core measures the altitude. 


4. Final observation.
When I have reached the initial starting point, at that moment the Core was reading 177m, so some 4m difference where it should be. 
However, after a minute or so it went up to 180m where it remained. I was amazed, as this showed the real altitude -0,5m. And that is already quite precise measurement!!!


On this small altitude difference (35m) the Core proved to be precise (-+ 0,5m / 1,5ft), but you need to give it a time to make the readings actual and display current information. At the top of the hill I did not allow the watch to correct the final readings and went to resetting the reference. I think if I'd wait, the Core would adjust the readings. 


Can you pls share your experience with altitude measurement and its precision ? Thanks. :-!


----------



## Seamaster73 (Jul 12, 2006)

I did a similar test on mine, taking it to the top of the Tour Montparnasse, the famous Paris skyscraper earlier this year. It was spot on. Very impressive.


----------



## Jeff_C (Feb 11, 2006)

You can look HERE for a static test I did.

I have taken mine on some local rides. I travel up and down a LOT... and when I get home its usually right on or only a few feet off.

Pretty impressive. Im convinced that the Auto mode is helpful in keeping things in check over the long haul. Evidenced by my "static" test.


----------



## Reed Kingsley Dagg (Dec 22, 2007)

Very cool Jeff_C,

Wish I had more time to read the forum right now. Still busy with christmas, but my significant other is absent this morning and as of late...her new horse I got her for X-mas..she's been a lot lately! It's all part of a plan fellas. Must be a guy thing=)

Although I've yet to 'officially' de-box my core, and it is sitting outside until I commece our list stress testing. (I am recording measured temperatures and relative humidity around the watches conditions) On a side note, day two outside, the Suunto was extremely screen lazy and at times difficult to read. However, good news is there is absolutely no sign of humidity in the watch or watch face whatsoever! 

Point, THE ALTIMETER...I have been using my mobile GPS, which is actually a USB GPS receiver that runs with 2007 Microsoft Streets and Trips software. I have it running with my laptop =) Speaking for the Microsoft GPS, the one time we had really put it to the test was on a road trip to the Smokey Mountains last year. It was a dead accurate measurment of our current speed when driving (according to the speedometer in the VW Passat) and bang on at every route map and elevation look-out we stopped at. Although it did loose GPS signal many times and we completely drained the battery on the lap top once while it was running, it always reboots and never needs a referance altitude to be set. Now that all said, I have set the actual GPS unit streaming from it's USB cable into the box beside The Core. Although I have set the referance altitude according to the GPS, the measured reading from The Core varies as soon as it is switched back manually from Baro to Alti. Understand that I can not use the 'Auto' mode yet because the watch sits in one place. If I didn't manually change it back and forth it would stay in Baro mode. Now, I reset the referance altitude in the Core three times. The GPS unit is still reading the exact same, in fact it is even to a smaller measured degree! Unfortunately, there must be something in the 'air' that is messing with it's Alti mode. Without looking into it further, yet, I have to assume that it is a software issue...although I am not certain.

Your thoughts?


----------



## Jeff_C (Feb 11, 2006)

This has been reported sevearl times and is common to many ABC watches. As I have said before, every one of my ABC's do this to some degree. If its a few feet or meters I wouldn't worry about it. If its MAJOR, then it may be an issue. 

Its important to realize that NONE of these watches are EXACTLY perfect. If thats what a user wants then they should go with a GPS unit like you have. 

Again, I have seen this exact thing with every one of the ABC's I own. 

YMMV.


----------

