Differencses in amplitude in Booms

Hi,

We are using two Raspberry Booms in our research to collect data, but we experience a large difference in our data. The amplitude difference is by almost a factor 10 between the two booms. Even if we use wind reduction system on the boom with the highest amplitudes, the amplitudes is still way higher than the boom right next to it without a WRS.
We also tested this in our lab, just to confirm that there is a problem.

Do you have any recommendations to fix this probelm?

Hello bjorn, welcome to our community!

Thank you for contacting us about this. It is indeed unusual, since their performance should be the same if they are located in the same spot (or, at least, close enough that the difference between the two is not created by their different positioning, as I am sure you have already checked).

Could you please post a couple of pictures for each BOOM, to verify that the microbarograph filter (the red one, if you haven’t switched for your research purposes to the yellow one) is in the correct place?

Could you also post sample datasets (even screenshots are all right, as long they show the discrepancy you are describing) and the logs from both BOOMs? You can download the log files following these instructions: Please read before posting!

Thank you!

Hi, thank you for the welcome and reply.
Form the hardware perspective, I can se a dent in one of the red tubes in boom 1, but this is actually the boom we are getting the “expecting” results.

Here are the pictures of the Booms:

Log files:
RSH.RCF56.2021-10-08T12_02_34.logs.tar (2.8 MB) RSH.RF32E.2021-10-08T11_51_03.logs.tar (3.3 MB)

Picture results:
Skjermbilde1

The time and date is:
UTCDateTime(‘2021-10-06T13:08:20’)

2 Likes

Hello again bjorn,

Thank you for both logs and pictures, and also for that very interesting data visualization of the two signals!

I will pass them to our hardware team so that they will be able to check that there is nothing wrong with the microbarograph setup. I will update you as soon as I have news from them!

Thank you for your patience.

Hi,

How is the prosess going?

I`ve done some more testing with our Booms, and we can that there are diffrences in the data collected (and a lot more noice in the RC32E).
I used signal 40, 30 and 20 Hz

I will do a new test on monday in a different loaction to see if the 7Hz signal is caused by the building eg.

Hello bjorn,

The last update was that our team was still looking through this, and sorry for the delay in answering you. We had a couple of issues with our services in the last days that took a bit to be solved by our team.

I will ask for another update, and give them this new (and very interesting!) data composition that you have sent me. Please, if you can, provide also something similar when you do the next test, so that the team will be able to look at that too.

Thank you very much for your time.

Thank you for the photos @bjorn .

Can you send new ones without glare? The best would be high quality photos of the tube that has the red bands.

Thank you!

Alberto

Hi @Albertof007 ,

Yes of course. As you can see from the pictures, the RCF56 has a bend in one of the two tubes. The strange thing is that this is the boom we are getting the expected results from.

RCF56:

RF32E:

Bilde 26.10.21, 08 15 53

Hello.

Sitting next to Alberto here. We confirm that all of this looks OK. Are you adding any additional tubing to the external nipple during your tests?

Attached are the results from the huddle test we ran on your units before they shipped. Each unit was run one day apart from the other and compared to reference unit R0044. I applied a filter from 0.2 to 10 Hz.

I now see these units were shipped over 1 year ago. In that time have you replaced or removed any of the filter tubes? Changing out, for example, the red and the yellow filters?

We will get to the bottom of this! Thank you for your patience.

yours, branden

1 Like

Hello, @branden

Thank you for the results from the huddle test.

To answer your questions:

  • The instruments was tested “as is” for comparison. No extra nipples, no additional tubes nor WRS.
  • No changes in the tubes. They are the same as we got them from you.

Is it possible to send the RF32E back to you, and get a new one?

@bjorn going to message you offline

branden