Elevation recording

Discussion related to the Garmin Montana 6x0 GPSr
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Mick F
Posts: 23
Joined: Tue Jan 24, 2017 7:09 am

Elevation recording

Post by Mick F » Fri Jan 05, 2018 9:10 am

I took my Montana on a flight last month and recorded the flightpath. Trouble was, the recorded elevation was dictated by the cabin air pressure and the "altitude" levelled out at 20,000ft ................... instead of the GPS readout at 38,000ft.

Is it possible to record the raw GPS elevation rather than BP?

Thanks,
Mick.

gpsrchive
Site Admin
Posts: 100
Joined: Fri Jan 20, 2017 11:29 pm

Re: Elevation recording

Post by gpsrchive » Fri Jan 05, 2018 2:30 pm

Try:

Setup > Altimeter > Auto Calibration > On
Setup > Altimeter > Barometer Mode > Fixed Elevation

Mick F
Posts: 23
Joined: Tue Jan 24, 2017 7:09 am

Re: Elevation recording

Post by Mick F » Sat Jan 06, 2018 6:52 am

Thanks for the reply.

I'll have a play with Monty later, but one thing puzzles me. On the Trip Computer page, I have one section displaying elevation. This elevation readout is BP elevation which is also influenced with GPS elevation. I calibrate the elevation at home at 222ft to force it correct. If I didn't calibrate it and left Monty outside for a some time, it would eventually drift to 222ft automatically.

By setting the Altimeter in Setup like you suggest, would the Elevation readout in Trip computer be exactly the same as GPS elevation? I can set one of the Trip Computer data fields to display GPS elevation of course. Would this GPS elevation now be the one that is recorded?

As I say, I'll have a play later today or tomorrow.

Thanks,
Mick.

sussamb
Posts: 23
Joined: Sat Jan 28, 2017 11:28 am

Re: Elevation recording

Post by sussamb » Sat Jan 06, 2018 7:33 am

GPS elevation will always vary from any barometric reading

https://support.garmin.com/faqSearch/en ... yoxITW2vZ6

Mick F
Posts: 23
Joined: Tue Jan 24, 2017 7:09 am

Re: Elevation recording

Post by Mick F » Sat Jan 06, 2018 12:06 pm

sussamb wrote:
Sat Jan 06, 2018 7:33 am
GPS elevation will always vary from any barometric reading

https://support.garmin.com/faqSearch/en ... yoxITW2vZ6
That's the point.

BP altimeter will always be at variance with GPS, especially if you are in a pressurised cabin on an aircraft at 38,000ft. ;)

My question was about how to record the GPS elevation instead of the BP elevation.

However, leave your Montana in the open, and eventually the BP will be very close to GPS elevation.

Mick.

gpsrchive
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Posts: 100
Joined: Fri Jan 20, 2017 11:29 pm

Re: Elevation recording

Post by gpsrchive » Sat Jan 06, 2018 12:31 pm

Mick F wrote:
Sat Jan 06, 2018 6:52 am
By setting the Altimeter in Setup like you suggest, would the Elevation readout in Trip computer be exactly the same as GPS elevation? I can set one of the Trip Computer data fields to display GPS elevation of course. Would this GPS elevation now be the one that is recorded?

As I say, I'll have a play later today or tomorrow.

Thanks,
Mick.
I have successfully (in the past) recorded many flights using a Montana GPSr and I believe those are the settings I used. You will need to be seated near a window and keep the GPSr as close as possible to that window for best satellite reception.

Mick F
Posts: 23
Joined: Tue Jan 24, 2017 7:09 am

Re: Elevation recording

Post by Mick F » Sun Jan 07, 2018 6:12 am

Tried it out and it works!

Set the Altimeter to "Fixed Elevation" in Setup/Altimeter/Barometer Mode.

BP Elevation will now be equal to GPS Elevation, so when you produce your GPX track in Track Manager, the elevation profile is the GPS elevation profile. This means then when I go on a flight again, I can record the correct height of the flight and not one that is corrupted by the internal cabin pressure.

Thanks very much indeed.

Mick.

gpsrchive
Site Admin
Posts: 100
Joined: Fri Jan 20, 2017 11:29 pm

Re: Elevation recording

Post by gpsrchive » Sun Jan 07, 2018 2:37 pm

You're welcome!

Happy GPSring!

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