Neptune indications wrong after transitions?

[MikeyT]

I recently purchased a Neptune Altimeter and was happy with it so far, until this happened:

In 1500m (5000ft) I am on my back watching a friend who couldn't keep up with me on a freefly dive due to stability issues.
My altimeter showed 1200m shortly thereafter my audible alarm set at 1100m went off while I was doing a transition onto my belly, I then again checked my Neptune (on my belly) and it showed 1200m again I waited for 1100 m (3600ft) to show and pulled.
Under canopy after rear risering towards the DZ (2sec) my Neptune showed 512m. Deployment is logged at 470m in the Neptune's Log. (500m = 1640ft)

I had a similar jump 2 jumps later where I was logged as deployed at 1900ft.

My usual distance between pull altitude and logged deployment are around 250-300m (1000ft).
My sequence is 1.pull altitude- 2.wave off- 3.pull.

I have the neptune on my left wrist, so it is in a burble when on my belly and in direct airflow when I am on my back. I also have the protective housing mounted- without the glass cover..

Other than on this occasion my neptune seems to be working normally

I am pretty conservative when it comes to pulling.. these are my first two low pulls, and I don't want to make them a regularity.

I have been using the neptune for about 30 jumps. Prior to that I had an Altitrack and never had similar problems.

Any advice?

[Roger Allen]

I recently purchased a Neptune Altimeter and was happy with it so far, until this happened:

In 1500m (5000ft) I am on my back watching a friend who couldn't keep up with me on a freefly dive due to stability issues.
My altimeter showed 1200m shortly thereafter my audible alarm set at 1100m went off while I was doing a transition onto my belly, I then again checked my Neptune (on my belly) and it showed 1200m again I waited for 1100 m (3600ft) to show and pulled.
Under canopy after rear risering towards the DZ (2sec) my Neptune showed 512m. Deployment is logged at 470m in the Neptune's Log. (500m = 1640ft)

I had a similar jump 2 jumps later where I was logged as deployed at 1900ft.

My usual distance between pull altitude and logged deployment are around 250-300m (1000ft).
My sequence is 1.pull altitude- 2.wave off- 3.pull.

I have the neptune on my left wrist, so it is in a burble when on my belly and in direct airflow when I am on my back. I also have the protective housing mounted- without the glass cover..

Other than on this occasion my neptune seems to be working normally

I am pretty conservative when it comes to pulling.. these are my first two low pulls, and I don't want to make them a regularity.

I have been using the neptune for about 30 jumps. Prior to that I had an Altitrack and never had similar problems.

Any advice?

I'm sorry to hear you are having problems with your Neptune.

If I am reading your e-mail correctly it t would appear that your Neptune was reading correctly at about 3900' "My altimeter showed 1200m shortly thereafter my audible alarm set at 1100m went off ", so freefall lag is not likely.

Wrist burble may cause a reading variation of 100-200 ft.

There is no obvious cause for the symptoms you describe.

Where are you located? I would like to make arrangements to get a replacement unit to you and put your unit in a test chamber and see what is going on. (Please Private Message me with this information).

Also, for reference, what is your serial number and software version?

Roger