Interference between stations - a cautionary tale
Posted: Tue 24 Sep 2013 5:09 am
Hello
I have a Vantage Vue. It was using Station ID 1, the default.
Lately I have been getting strange wind direction and wind speed readings. It can't be a sensor failure, because there are two sensors - the temperature-humidity-wind speed sensor at one end of the unit and the wind speed sensor at the other. I changed the wind direction constant using Weatherlink. Possibly better. Next time I looked it wasn't. So I changed it again. The default for VV in the southern hemisphere is 179. I tried 0, then 90 degrees, with no improvement. Then, confusion increasing, I thought I would set it back to 179, to I put in a calculated value of 358 for a displayed reading of 179 degrees. It doesn't immediately show you the correction value. You have to go back in. I closed Weatherlink and looked at the data. The wind direction was about right. Hmmm. It turned out Weatherlink had set the constant to -181 and the data was about right.
The Davis agent here in NZ asked Davis USA, who suggested I change the Station ID. The instructions in the manual (!) said something about other stations nearby. Clang - penny dropped! A while ago a neighbour installed a Vantage Pro. My console is closer to my ISS than his, but the signal goes through more walls between the console and my ISS than it does to his. The ISSes are about 100 m apart. Davis didn't know about the other station - I hadn't thought about it.
After setting ISS to STA 4, the console was still recording data for STA 1 when I got back inside! The wind direction was 180 degrees out. After setting the console to STA 4, wind direction returned to the correct place. Yay!
So, strange readings may not be a failure, they could be due to interference between stations. I have my fingers crossed that the problem is solved.
Graham
Tauranga, New Zealand
I have a Vantage Vue. It was using Station ID 1, the default.
Lately I have been getting strange wind direction and wind speed readings. It can't be a sensor failure, because there are two sensors - the temperature-humidity-wind speed sensor at one end of the unit and the wind speed sensor at the other. I changed the wind direction constant using Weatherlink. Possibly better. Next time I looked it wasn't. So I changed it again. The default for VV in the southern hemisphere is 179. I tried 0, then 90 degrees, with no improvement. Then, confusion increasing, I thought I would set it back to 179, to I put in a calculated value of 358 for a displayed reading of 179 degrees. It doesn't immediately show you the correction value. You have to go back in. I closed Weatherlink and looked at the data. The wind direction was about right. Hmmm. It turned out Weatherlink had set the constant to -181 and the data was about right.
The Davis agent here in NZ asked Davis USA, who suggested I change the Station ID. The instructions in the manual (!) said something about other stations nearby. Clang - penny dropped! A while ago a neighbour installed a Vantage Pro. My console is closer to my ISS than his, but the signal goes through more walls between the console and my ISS than it does to his. The ISSes are about 100 m apart. Davis didn't know about the other station - I hadn't thought about it.
After setting ISS to STA 4, the console was still recording data for STA 1 when I got back inside! The wind direction was 180 degrees out. After setting the console to STA 4, wind direction returned to the correct place. Yay!
So, strange readings may not be a failure, they could be due to interference between stations. I have my fingers crossed that the problem is solved.
Graham
Tauranga, New Zealand