Alti Measurements

[ach5]

I have noticed that even under the same conditions, my Riseman gives significantly different altitude readings in the same place on different days.

I calibrated the correct altitude - where I live is 195m above sea level.

On three days this week, with the same (off the wrist) temperature (+/- 0.5degC), I have had readings from 160 to 250m.

I keep re-calibrating it back to 195m, and then a day later it's way out.

Is this to be expected, or do I have a dud?

I LOVE this watch, so am hoping all will be ok!

[ach5]

PS, I know it relies on air pressure, but surely this shouldnt cause such a big difference, or it'd be useless as a tool as you cant calibrate temp AND air pressure just to get an alti reading.

[ThomAsio]

Hi ach5,

Changing air pressure, can have two causes: Changed altitude or changed weather. So when you need altitude readings, you have to calibrate the altimeter as often as possible. For instance just before you start a mountain trip.

This also goes the other way around: When your altitude change, your barometer will be of.

The Suunto's are supposed to be better in this regard, but it's the same physics behind it. So basically, you tell your Suunto "Today I'm climbing a mountain, so all pressure changes is due to changed altitude. Therefor, you (the watch) have to compensate the barometer". This is of course a handy feature. But if the altitude change AND the air pressure change simoultanous due to weather the watch cant figure out, what is what. They also got the opposite feature, you can tell the watch you're stationary, so all pressure changes is due to weather - keep the altimeter where it is, only change barometer.

My version of the Riseman, seems to be temperature compensated - the barometer/altimeter dont change if I put it in the fridge - I also have an older Casio alti watch, which is very sensitive to this treatment. Seems like it took Casio 15 years to implement this temp. compensating - I cant help but wonder if it'll be the same with the Suunto baro/altimeter style ...

[dougcee]

I think this is normal. I have a Kestral hand held weather station which does the same exact same thing. I believe you're o.k.

[cal..45]

@ ach5,

unfortunately you just found out one of casio's biggest ABC shortcomings - lack of an altimeter lock - the hard way.

the way your riseman behaves is normal, yet unfortunately not very useful. to make full use of an altimeter, a lock out is essential. this can be done either automatically (times WS4 for instance) or manually (tech4o traileader series). since i never had a suunto, i can't tell how they do it.

the incorporation of sea pressure level (along with current pressure) helps further to keep altimeter readings more stable, unfortunately this feature is also not found in any casio product to date.

so take your riseman for what it is: a very good, tough digital watch with great look, very good to read display, great "normal" functions and very basic altimeter/barometer functions.


cheers

[ach5]

Thanks for all the replies!