Spikes troughs and flatlines

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magical46
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Spikes troughs and flatlines

Post by magical46 » Sat Oct 21, 2017 8:29 pm

Hi
I am sure anyone, like me, who uses a FineOffset based weather station has experienced the title of this post. I just thought I'd ask if anyone has come up with a fix to stop it happening. My station goes for weeks without any issue then suddenly for no apparent reason it starts producing spikes (wind at 57.9mph usually along with troughs in dewpoint and temp). Last night for example from midnight to 2 in the morning continuous spikes, then all ok till about 4.30 and again some spikes, then all fine until 1735 this afternoon when again a spike.
I have Weather Display running 24/7 and these spikes really mess up the data, in MT I go through the data quality check and remove the offending lines (sometimes I do bulk editing but I find it better to do it line by line), I cannot get rid of these issues in WD though.
I know this has been an issue for years, as I have had several fine offset stations (I'm afraid for me it comes down to cost, yes I'd love a vantage pro with all the bells an whistles but it ain't gonna happen). I have searched to see if the manufactures have produced a patch or fix of some kind but can't find anything. Any ideas :?
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John B
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Re: Spikes troughs and flatlines

Post by John B » Sun Oct 22, 2017 1:44 am

G'day, magical46,

I do not own a FineOffset unit. However, on a number of occasions I experienced a similar phenomenon with a La Crosse station.

The first time I solved it was due to unreliable cable contacts. That result came about as it was cured when I cleaned thoroughly all the connections from all the units attached to the station and the station console. The last time it happened it wasn't that simple. After lots of cleaning it still didn't change the behaviour. I even bought a new rain gauge, transmitter unit and console - not all at the same time. Eventually, checking the cable connecting the console to the computer I noticed a crack in a couple of the wires' insulation. Further investigation showed that the internal wiring was broken but still touching most of the time. This resulted in intermittent contact through temperature, movement and just pure "inanimate-object" sadism. A new cable fixed it.

If you go down the cleaning track make sure you use a non-residual cleaner - most, if not all, methylated spirits and other domestic cleaners sold are not.

The same symptoms can also be caused by dry joints in the circuitry. These are really the same as the above except that the poor contacts are in the unit's electronics. It also means that unless you are happy to pull things apart and work, very carefully, on the FineOffset's innards, you will need help.

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Re: Spikes troughs and flatlines

Post by Johnny » Sun Oct 22, 2017 8:44 am

Hi Phil, I've never used Weather Display, but I too experienced the same problem and I use Cumulus which has options to remove spikes (see image below) Does Weather Display have any similar settings that you can use to resolve this?

I know this is not getting to the root of the problem - in my case I never did, what John suggests above is certainly worth looking at. The other thing to also keep in mind is that many electronic devices use the same frequency as our weather stations (433MHz), so something as daft as a door bell being rung could cause such a spike. I'm sure there are plenty of other sources of radio interference as well.

Cumulus-Calibration-Settings.jpg
Cumulus-Calibration-Settings.jpg (53.46 KiB) Viewed 8479 times
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Davis Vantage Pro2 Plus: http://www.watfordweather.uk Bloomsky 2 & Storm: http://www.watfordweather.co.uk

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Re: Spikes troughs and flatlines

Post by nikokara - BANNED » Mon Oct 23, 2017 4:56 pm

Hi magical46

In addition to Johny's and John's B post....

Stronger signal = less spikes

Try to turn 1-2 grad at the time either the transmitter or the receiver (console)
but be aware, you can lose the DCF signal if you have it and live in EU
and try to ground your transmitter mast

And check if the antenna length is
0,658198614 m = λ
0,329099307 m =λ/2
0,164549654 m =λ/4 <<===== This for 433Mhz
m=meter λ=Frequency
niko

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magical46
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Re: Spikes troughs and flatlines

Post by magical46 » Fri Oct 27, 2017 3:34 pm

Thank you all for the above replies, I think I will live with it till the summer when I will have chance to try some of the above.
Odd one today though, when I checked my site at work there was one spike at 0655 showing the usual wind spike value of 57mph, so when I got home I deleted it in MT but on checking my WD (with the intention of deleting it from the log files) no such spike was showing, checked the log file and that time showed wind of 3.3mph (and the lines before and after that time showed similar values) so that spike seemed to have occurred when the data was transmitted to my site.
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Re: Spikes troughs and flatlines

Post by weather display » Fri Oct 27, 2017 8:04 pm

you could try adding RF chokes to the data cable/USB cable
also WD does have data limits
i,e you can set a limit say for max gust/max temperature so that data above that is ignored
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Re: Spikes troughs and flatlines

Post by Ron » Sat Feb 03, 2018 2:32 am

I know this post is 3 months old, but I wanted to drop my thoughts in here since I solved something similar.

About 4 years ago, I had a fine-offset station, Weather Display software at the time on Windows 7. I would randomly get high spikes in wind-speed, and large dips in other readings at that same moment. If I remember correctly the speed was nearly always the same value.

It nearly drove me nuts. I finally realized, that just before the events started, I had hooked up a usb web-cam. (cheap one)
I unplugged it for a day and the spikes stopped, I plugged it back in, and the spikes randomly started again. Perhaps a timing issue with something the webcam was doing or the webcam generated a spike in the usb circuit when it performed some type of operation.

You never know, it could be a peripheral, generating garbage noise at random times, but the same strength. Webcam, usb hub, anything, may or may not be the culprit, but it is worth looking at,. For me it was the webcam. I replaced it with another, and all was fine.
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