Suspicious 0.0 winds

Tempest Owners
1

I now have my sky in non power save mode (for a short time) I see wind speed values going like 3.7 2.9 3.1 1.6 3.1 0.0 0.0 3.2 3.2 2.7 3.5 3.2 4.2 3.2 4.7 2.7 3.4 5.9 8.4 6.6 5.9 6.4 4.5 5.8 5.5 5.0 6.6 5.9 6.8 5.3 3.7 4.2 3.7 4.7 2.6 4.3 4.2 4.2 2.6 4.2 3.4 4.5 4.5 2.3 4.5 3.2 3.7 3.2 1.8 0.6 4.4 2.3 3.5 3.4 2.9 3.5 2.1 2.3 5.0 6.8 7.4 5.6 7.7 6.9 6.6 3.9 4.2 3.2 3.2 3.9 6.9 6.1 7.7 8.2 7.1 5.3 3.4 5.1 7.2 7.1 6.4 5.5 6.8 7.2 5.8 6.4 7.1 6.6 6.4 6.3 6.4 7.1 5.3 5.9 4.4 5.8 5.9 5.0 4.2 5.8 3.9 2.6 0.5 0.0 0.0 0.0 2.3 5.0 3.5 4.4 0.5 4.2 4.4 5.5. (real values typed while looking at the app, might have missed one or two).
I suspect these 0.0 values aren’t real. I would have expected measurements like 0.1 0.4 etc. Is the app perhaps reporting 0.0 when a measurement fails? If so are are these 0.0 used to calculate the average speed? If it are failed measurements, are these flagged as such?, shouldn’t the display show ‘—’ instead of 0.0.
I think it is just suspicious how many times the minimum wind within a minute is 0.0 for my station. And that is mostly seen when my station is in power save.

Of course it might be real, but it is what it is… suspiciuous.
(station is now back to power save mode)

2

Perhaps, it is an effect of rounding or minimal detection threshold ?

3

Is this post another example of the issue?

Seems unlikely that with average wind speeds of 30 (mph) and gusts up to 70, that there could be a reading where the wind is absolutely still.

4

that could be, but I have seen on occasion a value of 0.1 (this morning at 08:52 for example) so the system is capable of measuring very low values). There still might be some rounding before conversion to km/h going on. The values I do get to see are 0.0 0.1 0.3 0.5 0.6 0.8 1.0 1.1 but no 0.2 0.4 0.7 for example.
Today it is super calm weather so the 0.0 is now very possible. But the question is more about when it isn’t that calm, and i think it still shows a preference for 0.0 over any other value below 1.0

5

indeed that would be highly unlikely.

6

No. My readings were zero because wind was strong enough to snap poles on the transmission line bringing power to the island

7

I think we might be referring to two different periods of time. The gap in your data starting midway through September 6th is due to the power outage. Before that time though, the average wind speed (blue line) increased from 10 to 30 mph and the gust (red line) from 20 to ~70 mph. The “lull” speed or minimum speed (green line), however, stayed fixed at zero. This just seems unlikely given how fast the winds speeds were becoming.

8

Except that there should be no readings at all then.

9

Ok, I see what you mean. Here’s a closer look - does this help?

Screenshot_20190908-102637
Screenshot_20190908-102637.png1080×1920 166 KB

10

Hi @sunny, In the past I used a video of my screen to record each 3 sec value and calculate the average. It might be helpful for you to display and calculate the possible error. Here is where I show the video and discuss the issue I had (look at the history in that discussion for more info):
https://community.tempest.earth/t/wind-speed-seems-to-be-reading-low-solved-in-firmware-v103/1510/50
cheers Ian :slight_smile:

11

I’m not sure how a video could help in this case as it reports 0.0 wind in the 3 seconds measurements or 15 seconds measurements. I just don’t believe this many 0.0 even on a calm day without having many 0.3 (even though i realise that I’m looking at the minimum, which might easily make the amount of 0.0 two or three times higher, but it is just more)