Topic: Fluctuating Temps on Cabled VP1

[colonieweather]

Hello everyone.....

A problem has reoccurred just recently as this weekend and continues this evening and I'm getting a bit frustrated.

I have noticed that my outdoor temperature readings on my cabled Vantage Pro 1 are flucuating frequently. For example, the temperature was 13.3F and it suddenly jumped to 15.4F then went back to 13.3F and then to 14.2F and back to 13.3F... It would eventually return to normal for awhile...then do it again. It has occurred a lot since starting or when I noticed it....it happened several times around this time last year...it seems like only when it is very cold. I really have no explanation as to why this is occurring...I was wondering if anyone might have been in a similar situation or maybe has a solution??

I did check for splicing of cables and there was none....and most of cable is underground in conduit. I do have a rain gage heater and it was on during the issue (because it was snowing)...but I did shut it off to see what would happen and it still did it...

I also tried unplugging the cable from the console to my computer to see if it was a grounding issue (recommended by someone on another forum) and the fluctuations continued....

The temp/hum sensor is brand new as of last year...Davis thought it might be the sensor as I did contact them about the problem when it occurred before and had it replaced....also contacted them again today and got same freakin answer...replace sensor for $70...I don't believe that is the problem....

Thank you,

Chris

I sat at my computer with WeatherLink open and recorded the temps as the changed (about 3 minutes).....

12.6
13.8
12.8
13.3
12.8
13.6
13.1
12.8
13.3
12.8
13.8
12.8

[Mark / Ohio]

Any chance that reading could be correct in that air currents from some heat source could be reaching the sensor?

I live toward the top of a hill and sometimes when the winds are calm or very light I'll see some variations.  I've always figured it to be air currents moving either up or down the hillside.  Cloud cover seems to have an effect as well.

[colonieweather]

I'm not really sure....I have it located in the middle of my backyard....and my land is pretty flat...and it was occurring last night under a crystal clear sky with a foot and a half of snow on the ground.

Does your temps jump like that too??  From lets says 12.1 to 13.0 just like that then return to 12.1 a second later...I feel like it might be some sort of interference but it is a cabled unit though...and it only happens when its very cold...its just weird...

[George Richardson]

Chris,
I have no idea what your problem might be but. . .
Welcome to the forum, very nice web site.
George

[Mark / Ohio]

....Does your temps jump like that too??  From lets says 12.1 to 13.0 just like that then return to 12.1 a second later...I feel like it might be some sort of interference but it is a cabled unit though...and it only happens when its very cold...its just weird...

I've never noticed mine changing that much in a few seconds.  It is more gradual probably only changing a full degree over a period of minutes.  My ISS with the temp sensor is mounted about 6' above the ground.  Also I'm running a wireless unit.

[jchen]

Rodent or bird?

[Mark / Ohio]

Rodent or bird?

A squirrel with hot breath stashing food in the radiation shield.  I'll bet that's what it is.      

[colonieweather]

interesting revelation.......I noticed something else go when my temperatures would flutcuate.....wind direction would go to due north on console and stay......

Before I discovered the latest isuue w/ the wind I had spoken with Davis and ruled out temp sensor which has already been replaced as was the SIM board....recommmended sending it in for repair...which I don't want to do...but now with the wind issue too happening at the same time??  I don't know what to do.....was thinking of just getting the VP2 ....

I'm thinking grounding issue somewhere....but I unplugged the cable to the computer and it didnt fix it....and unplugged console....

[Mark / Ohio]

...I'm thinking grounding issue somewhere....but I unplugged the cable to the computer and it didnt fix it....and unplugged console....

My cousin did have a wind speed intermittent jump when it started raining or storming from a ground loop issue on a wired VP.  Grounding the case of the computer to a cold water pipe seemed to resolve that for him.  But since you've tried unplugging the console from the computer and AC line that would seem to rule that out.