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No Velocity Data/QC Warnings?

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Euan-Angus MacLeod

Hi all,

I recently retrieved an Eco we deployed last month but no velocity vectors were part of the data (all values "nan"). Without QC warnings, I don’t have any way to work out why this is and how to make adjustments. It appears that the depth of the sensor met the minimum 60cm of depth to get all three layers and nothing could be identified as interfering with the acoustic cone for the full deployment. Has anyone else had this experience? 

When our client was informed, they were pretty annoyed that no velocity data was collected and there was no apparent reason why. Having a couple of error messages would be helpful during the post processing stage. 

Thanks,

Euan

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    David Velasco

    Hello Euan

    Thank you for the feedback, and sorry to hear you didn't have a successful deployment this time.

    Can you confirm the orientation your Eco was deployed, and how it was installed on the stream?  The Eco can only operate in up-looking orientation, so that would be an easy thing to check.  Full blockage of a beam will also cause data loss, although this would have to have happened for the entire deployment.  Another thing to check is excessive tilt.  Unfortunately, there's no clear-cut threshold for tilt, and it's also a function of water depth, but in general, you want to keep the Eco as vertical as possible to maximize data return.

    Best regards,

    -Dave

     

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    Euan-Angus MacLeod

    Thanks, Dave, 

     

    It was upward facing using the tripod for support. The tripod was secured to the bank using a 1/8" crimped steel wire tied to one of the legs. Tilt values appear to be between 4 and 8 deg as read from the results .csv. From what you're saying it sounds like something must've been interfering with the beam despite nothing being wrapped around the Eco when it was retrieved; I redeployed the Eco in a different location and it collected data as expected.

    If Nortek could add QC warnings for beam blockage etc, I think that would be a valuable addition to the measurement readouts. 

     

    Cheers,

    Euan

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