Topic: OS vs Davis ?

[Snowda]

Oh, how slippery the slope.  We wanted to get a good rain gauge so that we'd know if we needed to water our gardens.  (No, this really isn't as stupid as it sounds, it's not unusual for it to rain where we are at work, but not at home 10 miles away and I work in a theatre so sometimes wouldn't know if a tornado hit.)  There are some decent seeming rain gauges for $50 - $75, but if spending the money and mounting the thing I thought it might be fun to get a little weather station since we live in MN and do get some interesting weather.  

The OS WMR968 is appealing at $189.  Am I just asking for headaches with this?  Does it do what it does well but just doesn't have some advanced features of the Davis and doesn't update as often?  How important are the accuracy and update interval differences and when would I be likely to be complaining if I had the OS?

Thanks,

[ANPweather]

Another to consider is the Honeywell TE923W (and they're coming out with a TE824W). Sold overseas as Irox and one or two other brands. It's $20-30 more than the OS. I haven't found many reviews online but from what I've found they may be somewhat better quality. For example sealed battery/electronic compartments on the Honeywell and not on the OS.

That said I'm leaning toward the Honeywell but haven't got out my credit card yet.

[Snowda]

Funny you should mention that one. I was just looking at it on ambient and one interesting aspect is very affordable remote temp sensors.

[jwyman]

Depends of course on the size of your wallet....

Ihave an OSI and like it for the most part.... IF you are really serious into weather then get a DAVIS. I plan to do that later when the time is right....

Jim

[windy]

the OS or La Crosse or Irox stations are good starting off stations
but the serious observers later upgrade to a Davis station  

[Snowda]

but the serious observers later upgrade to a Davis station  

Why?  

Reliability? Acuracy? Update Intervals? More data? Easier to use? Features? Keeping up with the Joneses?

Thanks,

[windy]

because davis stations have good quality reliable sensors and great back up service and fast update rates of the data and a great data logging for when not connected to a pc....
The vast majority of people sending data to the CWOP are Davis VP owners, just to show how popular they are

[Anthony]

I currently have an OS WMR-968. It has served me well in over 5+ years of operation. So far I've only had to replace the anemometer and it's transmitter. As the others have said. It's a good starter station. Down side. Slow update intervals for wind speed/direction, rain is measured in 0.04" and not 0.01 like the Davis & from what I hear. Customer support is all but non existant on the OS products.

As for the Davis. Better update intervals, better quality, more sensors to choose from & I hear the customer support is great.

So it's all just a matter of how serious of a weather observer your are and how big your wallet it.

[CookevilleWeatherGuy]

Snowda....depending on your tolerance for digging into your pocket, I would go with the Davis..it is BY FAR the best.....then I'd back it up with a PROFESSIONAL rain gauge (for the garden)...the best one I've found is located by clicking here....

[Snowda]

Thanks for all the info.  Still researching and debating.  The cost dif between the OS or Honeywell and Davis is considerable though I'd rather spend the money now than spend $200 and be sorry.

Thanks everyone.

PS, Has anyone used this detail of weather information to improve gardening at all?

[Ravenstar]

Lots of good advice here. When I was looking for a WS I boiled it down to these same two stations. I was very tempted to go with the OS because of the savings but made my final decision reading thru posts on the Ambient forum (I hadn't found this forum yet 'Gary's original'). Saw too many people having problems with the OS and very few with the VP 2. That cinched it for me.

This doesn't mean there aren't a lot of people happy with their OS stations, they just seem to be the silent majority.

[jaded]

Has anyone used this detail of weather information to improve gardening at all?

Absolutely. Davis systems are marketed to farmers, nurseries and other commercial businesses, and are used to determine soil moisture and how much supplemental water is needed.  Given that fuel costs are among the highest costs a farmer can incur, irrigation can be quite expensive especially in a drought year.

One of the nice things I like about Davis is the wide variety of sensors.  They offer soil moisture sensors so you can tell precisely when to water, and soil temperature sensors for knowing when to plant.  Even without the soil sensors, if you have a solar sensor one of the values a Davis station will compute is "evapotranspiration", an estimate as to how much water is in your soil based on wind, air pressure, temperature, etc.

A Davis console can also be interfaced to a set of "alarm" relays.  You can set certain parameters that will operate equipment (rain and soil moisture levels could control your sprinklers, inside temperature could sound an alarm if the temperature dropped to the point where your pipes are about to burst, etc.)  It's quite the versatile environment monitor.

The drawback to a Davis system is, of course, the cost.  You can spend anywhere from $495 for their low-end solution to thousands after adding transmitters, sensors, loggers, etc.  I wasn't sure about the cost at first, but I bought the wireless pro and I've been amazed at how often I refer to it, and how much my wife likes having it, too.

And sure, we could have gone with an Oregon Scientific or La Crosse station, but after reading various forums about peoples experiences, I was sold on a Davis station.

Of course if you're only looking for a way to shut off your sprinklers on rainy, cold or windy days, Hunter, Orbit, Toro and other manufacturers make shutoff sensors designed specifically to control your sprinkler system.  They're convenient to install and usually much less visible in your yard than a full weather station, but they're just on/off switches and don't provide you with readings.

[WeatherHost]

Haven't had any problems with my OS wired (yet).  Whe it dies, I'm not sure what I'll get since I can't find a duplicate.

[brad3k]

This is truly a tricky question.  My experience may help guide your choice. In summary, the Oregon Scientific is not an out-of-the-box accurate/precise solution. You need to make modifications to acheive readings that are accurate/precise.

I have dabbled with weather monitoring equipment for a few years - focusing on manual precip. measurements. My youngest son wanted a weather station, so I bought a WMR968. I didn't want to spend much on a potentially passing hobby for him.

When he first set up the outdoor sensors, we noticed a huge discrepancy with our temperature and humidity readings from my manual readings, as well as from the local weather values. The out-of-the-box sensor in my opinion and experience does not have adequate radiation shielding.

After extensive modifications to make the thermo-hygrometer measure closer to it's design limits (i.e. fan aspirated radiation shielding), the readings are in line with what we would expect.

Also, the base station is not very practical for me or my son. I was able to make adjustments to the barometer to read at sea level (+- 1 mb), but the base station didn't allow us to make adjustments to the thermometer or dew point readings to accurately calibrate the values the sensors are reporting.  

I would recommend hooking the base unit serial port to a pc and install a weather logging software package to adjust the values from the instruments. We use my son's pc to track the results from the station, and don't even look at the base station.

The wind speed/direction issues have been well documented with this station.  I have had no problems with the unit, other than a freeze-up during an ice storm.  If you are OK with long period averages as we are, then this is not going to be a major factor in your choice.

I noticed that the documentation for the WMR968 doesn't mention the sensor accuracy. The documentation does mention "resolution".

From personal experience with one station here is what our station shows:

When comparing our readings to the MADIS values, the barometer shows a standard deviation of 0.5 mb.  The temperature shows a SD of 1.4 deg. F. and the dewpoint shows a SD of 1.7 deg. F.

The precipitation level matches my manual rain gauge within a millimeter or so, but I haven't taken the time to do a statistical comparison.

I have not called tech support, so I can't comment on them.

This is just one experience.  Take it for what it's worth.

[Snowda]

Thanks for everyone's help.

Brad, do you think your temp issue was the OSI probe or would any other mfr's system have given similar readings without a fan aspirated shield?

Thanks,

[brad3k]

I think a fan aspirated system gives the best results.  A colleague from work owns a Davis system and installed the fan aspirator and saw an immediate improvement in accuracy.

[glorfindeal]

While it cost even more, the Davis Vantage Pro 2 allows you to connect a soil moisture station which will give you a definitive answer to whether you  need to water or not.


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[carterlake]

While it cost even more, the Davis Vantage Pro 2 allows you to connect a soil moisture station which will give you a definitive answer to whether you  need to water or not.


Glor[/list][/i][/url]

Correct, but you can do the same thing with 1-wire (and a lot more work)... for a lot less.

One thing about Davis, you pay for convenience. If you can afford it, the wireless is definitely the most plug-n-play weather station on the market. And that includes all the add-ons.