automatic elevation calibration don't work at all

Discussion related to the Garmin Montana 7x0 series GPSr
Bebo20aug
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Joined: Wed May 05, 2021 1:47 am

automatic elevation calibration don't work at all

Unread post by Bebo20aug »

automatic elevation calibration, once o time nor continue, dont work.
putting elevation on 10000m and set automatic cal. to continue elevation start slowly counting down.
that seem oké. I am on 15 m
putting elevation on 1000 m it dont do anything.
by the way ofcourse gps accuracy is very good: 3 m.
On my Oregon 750 everything works oké:
with good GPS accuracy baro elevation tends to GPS elevation rather fast, without counting descent meters.
very good!
Is this a bug or is my Montana 700 not oké?
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GPSrChive
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Re: automatic elevation calibration don't work at all

Unread post by GPSrChive »

Start an activity recording....
Bebo20aug
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Joined: Wed May 05, 2021 1:47 am

Re: automatic elevation calibration don't work at all

Unread post by Bebo20aug »

I did that already. start automatic by setup
Bebo20aug
Posts: 8
Joined: Wed May 05, 2021 1:47 am

Re: automatic elevation calibration don't work at all

Unread post by Bebo20aug »

experiment:
manual calibrate altitude to 10000m
set automatic calibration to continue
start activity
nothing happened
restart device
altitude start to tend to my elevation at 15 m with 2m/sec very slowly
I dont wait for more than an hour and RESET my activity and then......
The altitude also reset back to 10000m!!!
same experiment but now manual to 100m
nothing happened
so I restart device.....
new altitude: 105m and no tending to my level
clear activity, altitude back to 100m
GARMIN GARMIN will this Montana become the successor of my Monterra?
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GPSrChive
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Re: automatic elevation calibration don't work at all

Unread post by GPSrChive »

Knowing what I do about how Garmin devices 'remember' manual elevation calibrations, I am hesitant to deliberately configure my device with such a large error.

In fact, my Montana 7x0 has always been accurate enough on its own I do not believe I have ever performed a manual calibration for the elevation value.

Perhaps a full device reset and not modifying the elevation calibration after may provide you with suitable results? Certainly teaching the device that your elevation is two or three or more times from the actual value is not going to contribute to meaningful operation.
Bebo20aug
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Joined: Wed May 05, 2021 1:47 am

Re: automatic elevation calibration don't work at all

Unread post by Bebo20aug »

sorry I started this issue with a wrong word Elevation while I was meaning Altitude.
later on I used the right word.
manual or automatic one have to calibrate the barometric altitude because of atmospheric changes of the pressure
when the weather comes into a depression, lowering pressure it seem one gain altitude while staying on place.
for that Garmin always give a feature to actualize, calibrate to actual altitude.
one can do that manual with known info (p.e. I live at 15m) known baro related to seelevel or given by GPS
If you re not interested at all in altitude but only in elevation data there is no need of calibration. but altitude info may not be oké
While mountainering accurate altitude is of great inportance. So one has go calibrate
With my eTrex Vista, GPSmap60, 60Cs, 60Csx, Oregon 450, 550, 600 and 750 I used to continue automatic calibrate.
That means when GPS position is very oké the altitude is also oké. from that moment the barometric altitude tends to the GPS altttude.
For testing its behaviour ot a new device one can misleading the device with a manual wrong altitude
by the way mis indication by barometric causes can be + or- 200m or more.
back to my previeus input: Oregon 750 works perfect, Montana 700 is totaly idiot on this issue!!!
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GPSrChive
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Re: automatic elevation calibration don't work at all

Unread post by GPSrChive »

"Altitude is typically only used to describe the height of an aircraft in flight. It is a barometric measurement expressed relative to the height of a runway or mean sea level in a given location or region (taking into account current local atmospheric conditions), or to an arbitrary standard datum (to eliminate the effect of localised variations in air pressure).

Elevation is usually used to describe the height of the ground, or a feature fixed to the ground. It is a geometric measurement expressed relative to the mean sea level datum established for the region by the national mapping agency."
Bebo20aug
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Joined: Wed May 05, 2021 1:47 am

Re: automatic elevation calibration don't work at all

Unread post by Bebo20aug »

altitude or elevation, names are not the problem. The totaly idiot behaviour of the Montana 700 regarding to alt. / elevation is the problem!!
truckinguy
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Joined: Mon May 27, 2019 11:37 am

Re: automatic elevation calibration don't work at all

Unread post by truckinguy »

I too use only the default by Garmin. I can tell you you I need to start the unit for a few minutes or so before using so it can calibrate and give acceptable accuracy. And depending on how much you use it and how far from the last spot will effect the timing. These recievers just can calibrate instantly under all circumstances.
With these units you'll never have perfect elevation or altitude data. Over the ground these units (older gps's too) give better data but not for altitude.

My 680 Montana needs more time at the start of the hike to calibrate so the elevation is close before I start a hike for the day. The 700 seems to do it faster. Maybe Galileo vs Glonass? who knows.
Bebo20aug
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Re: automatic elevation calibration don't work at all

Unread post by Bebo20aug »

sorry this all has nothing to do with barometric calibration. only about getting a reliable (3D) lock.
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