Hi Duke,
Thx for your response and input. Dabis uses a sensirion sensor and compared to a calbirated fast reponse datalogger it has the difference sit has. I use a Vaisala radiation screen (KNMI) for that sensor. The Davis is next to it in its own radiation shield. It is already "calibrated: agfaisnt it. In the past I have had Weather Wizard 3 and a WM2 in a Stevenson screen together with two calibrated min/max mercuty thermometers and much the same differencces were measured. Others have noted the same thing. Moreover Davis themselve guarantee a 0,5 K deviation from the real temp between -20 and +20 (range I am not entirely sure). Their radiation shield is pretty good, but it is not black inside which on very radiant days will add a little to the error. You cannot expect pro performance from a setup tjhat is only 600 euro and that is why I am okey.
The raingaugs are known to be highly inaacurate. BTW: I got mine cleaned just the day before and checked the airbubble in the shield that indicates the wether it is level or not. It is dead in the middle.
I found the Peet Ultimeter two things:
- The tempsensor (but I did not test the temohygor sensor!) is incredible. it is dead on. Just out of the box dead on. It is dead on the minima and dead on in the maxima. I mean within 0,2 K from a calibrated logger in the same shield. The fast response means this IS easy to calibrate. With davis last year I had for instance -13,3 with the datalogger and -12,8 on the Davis. But when it comes to the max. it registers lower. That is difficult to correct for. Mind you out of the box the deviations was more on sided, so the minima especially were way too high.
- Peet registers every 0,5 or even 0,25 s. For wind this is according to WMO standards. It also starts to spin at 0,1 m/s.
- Peets small raingauge has a system that is non tipping bucket. It was dead one. It standardizes the siz eof dropplets coming through. Everytime one such drop means a 0,25 mm or 0,1 mm (yes it registers that!) precipitation. You need larger funnel to register the latter. Which costed me 12 euro or so. The advantage here is that in high downpoors the tipping bucket simply splashes water away. Also if the pluviometer is a bit of balance it does not influence it as much as the tipping bucket which now will not tip at equal amounts. But the latter simply means you need to be accurate.
I am in a commission that writes the guidelines on equipment for the Dutch Society for Weather and Climate and my task is to set the standard for accuracy of the insturments used and the siting and how a station should be sited. It means I probably know a bit more than the average weatherbuff on equipment and how to measure according to some standards/ My reports on the Davis are not unique, they are pretty common.
The Davis to my mind is however ideal for home use and for the money it is incredible value. Also it is so reliable even wireless that it makes Peets claim that wires are so much more reliable a bit laughable. Their station especially lacks usable software like Cumulus. They appear not to be very helpfull towards the maker of Cumulus. You can use Weather Display which I do not like nearly as much as Cumulus and WUHU. Wuhu was okeyish...
And that is a bit sad I think. I plan to use a minipc (like E3350 minisystems) with this Peet, connect it via WifI to a MIFI router and let it run on solar power. A fun project to do. But it will be timeconsuming I think. Well: I fear...
