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Discussion Starter #1 (Edited)
Hello everybody,
Just browsing through the T-Touch related threads I realise that there appears to be a general misunderstanding of how the altimeter in the T-Touch - or any other altimeter - is supposed to work.
It has been suggested that the T-Touch altimeter has a problem due to sensitivity to weather change. This is NOT a problem. It behaves exactly like it should.:-!

I own a T-Touch Expert, and as a field geologist, I have extensive experience in orienteering in difficult terrain and using compasses, altimeters and GPS devices.

There are two main ways to measure altitude on the ground. One is by triangulation relative to satellites (the GPS system).
The other way to measure altitude is by observing variations in air pressure relative to altitude.
Using a certain formula, your altimeter (I.E. your T-Touch) converts the ambient pressure into altitude. Ambient pressure changes as a function of altitude: At higher altitude, the air pressure is lower, and at lower altitude, the air pressure is higher.
However, air pressure also changes as a function of weather: Bad weather usually accompanies lower pressure, and good weather usually accompanies higher pressure.

The T-Touch tries to compensate to remove weather effects by measuring the rate of pressure change and trying to determine whether it is an altitude effect or a weather effect. However, this is difficult to do because usually people also move around at the same time and the air pressure change is therefore generally a combined effect of varying weather and altitude. Therefore, there is always a slight drift, even though this effect is quite low relatively to other altimeters (A mechanical altimeter, for instance, cannot compensate at all).
The altimeter in the T-Touch Expert is also temperature compensated and normally, non-extreme variations in temperature (the watch temperature will by buffered by the temperature of your wrist) will not affect altitude readings to great effect.
All in all, the T-Touch altimeter is actually very good and *much* better than other models I have used (Thommen, Casio etc) if used properly.

Therefore, if you want to have altitude readings as precise as possible, you HAVE to calibrate your altimeter as frequently as possible; that means that if you start a day's hike, calibrate your altimeter relative to the parking lot where you leave your car. Or if you reach the summit, recalibrate the altimeter to the indicated altitude if required.
To repeat myself, ALL altimeters fuction this way.
For some technical reading see: http://www.biber.fsnet.co.uk/altim.html

Cheers,
Roelant
 

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Registered
Joined
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904 Posts
Hello everybody,
Just browsing through the T-Touch related threads I realise that there appears to be a general misunderstanding of how the altimeter in the T-Touch - or any other altimeter - is supposed to work.
It has been suggested that the T-Touch altimeter has a problem due to sensitivity to weather change. This is NOT a problem. It behaves exactly like it should.:-!

I own a T-Touch Expert, and as a field geologist, I have extensive experience in orienteering in difficult terrain and using compasses, altimeters and GPS devices.

There are two main ways to measure altitude on the ground. One is by triangulation relative to satellites (the GPS system).
The other way to measure altitude is by observing variations in air pressure relative to altitude.
Using a certain formula, your altimeter (I.E. your T-Touch) converts the ambient pressure into altitude. Ambient pressure changes as a function of altitude: At higher altitude, the air pressure is lower, and at lower altitude, the air pressure is higher.
However, air pressure also changes as a function of weather: Bad weather usually accompanies lower pressure, and good weather usually accompanies higher pressure.

The T-Touch tries to compensate to remove weather effects by measuring the rate of pressure change and trying to determine whether it is an altitude effect or a weather effect. However, this is difficult to do because usually people also move around at the same time and the air pressure change is therefore generally a combined effect of varying weather and altitude. Therefore, there is always a slight drift, even though this effect is quite low relatively to other altimeters (A mechanical altimeter, for instance, cannot compensate at all).
The altimeter in the T-Touch Expert is also temperature compensated and normally, non-extreme variations in temperature (the watch temperature will by buffered by the temperature of your wrist) will not affect altitude readings to great effect.
All in all, the T-Touch altimeter is actually very good and *much* better than other models I have used (Thommen, Casio etc) if used properly.

Therefore, if you want to have altitude readings as precise as possible, you HAVE to calibrate your altimeter as frequently as possible; that means that if you start a day's hike, calibrate your altimeter relative to the parking lot where you leave your car. Or if you reach the summit, recalibrate the altimeter to the indicated altitude if required.
To repeat myself, ALL altimeters fuction this way.
For some technical reading see: http://www.biber.fsnet.co.uk/altim.html

Cheers,
Roelant
Good one Roelant. Many dont realise that instruments, especially even percision instruments needs regular calibration. Much less a side feature of a device that is meant mainly to tell time. :-!
 
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