General Weather Station Data Handling Question

[bippen]

Hi everyone,

I'm a newbie to the forum and have spent the last couple of weeks pouring over manuals from the various manufactures studying and comparing specifications of many weather stations as I determine which system will be my see-if-I'm-interested-enough-to-spend-way-more-later station.  I'm an avid amateur telescope maker (a geek through and through  ) and just completed my dream telescope, a 20 inch Dobsonian which in the end cost me about that of a small car.  As such, while I'm very aware that Davis is probably the most reputable and reliable station, I do have a strict budget on this one....around $200.....but I do want to get into the world of personal weather observation.  I am an amateur radio operator and trained SKYWARN spotter as well, so this next step makes a lot of sense.....ok, so maybe geek is too gentle, I could be bordering on nerd....but don't tell my family!

The system I am zeroing in on is the OS WMR968 and it seems to have some pretty good reviews on this forum, lest some technical issues from time to time with some of the sensors and data connections.  I'm OK with tinkering and trouble-shooting, I'm a database and web programmer, I HAVE to be.  OK, here is my question......On all of the specifications for the various stations I've paid close attention to the transmission intervals of the sensors, most aptly the WIND sensors.  I've seen intervals from 2.5 seconds (Davis) to as much as 128 seconds (Zephyr's) and was wondering if anyone could clear up the following for me.  The OS WMR968 has an anemometer transmission interval of 14 seconds, I assume that means the sensor sends both a point reading (for the console to display) AND the continuous readings for that ENTIRE 14 seconds to be stored for download to a PC which allows for daily GUST values and so on.  Is my assumption correct?  In other words, even though the transmission intervals can be long (for power concerns), I would still have the continuous data from the entire day?

OK, I hope this makes sense and I look forward to hearing from anyone with some insight, your time would be greatly appreciated.

Kevin.

[Bushman]

According to the manual, the OS WMR968 determines gusts every 14 seconds and averages every 60.

[SlowModem]

I was going to post the link to the radio shack manual for the 968 (it's much easier to understand and more detailed) but I had to search for it.  I found the post where I had listed it before and it's got other info on it as well.

http://www.wxforum.net/index.php?topic=5371.msg48407#msg48407

Good luck,

Greg 

[d_l]

Have you looked over the new Davis Vantage Vue specs and prices?  For a little over double your budget price (depending on where you purchase it), you could have Davis system specs and a computer hook up to record weather data.

Unless you live at a dark site, you probably will be traveling with that gigantic Dobsonian.  One interesting aspect of the Vantage Vue could be its relative transportability.  I think you could carry it with you to observation sites and rapidly set it up on a portable tripod/mast to monitor and record local wind, temperature, and dew point conditions.

[bippen]

Thank you all for your replies, the numbers match the numbers I had found and I'm glad I had the right Radio Shack manual to look at as well.  I do travel with my telescope to specific dark sites in my area....and between weather stations that exist at those locations and my 2 meter radio which can receive current NWS conditions, the portability of this unit isn't a priority at this point.  A great great suggestion though, I didn't even think of that aspect of the Vantage Vue.  My budget on this project really must stay around $200 

With the OS WMR968, I'm trying to determine if a maximum wind gust occuring on second 10 would be recorded.  Is the sensor collecting continuous data and sending it to the console for storage in 14 second chunks?

I don't mind having the console update every 14 seconds, just hoping that the data I download to my pc is continuous (smaller interval) at the end of the day.

[Bushman]

AFAIK, no consumer level weather station will do continuous wind.  Even my Davis is every couple seconds.  Worse, some staions only report 1/16 compass points for  direction.  Why do you need continuous wind?

[SlowModem]

I have thought and thought and don't know the technical answer for this question.  What you may want to do is find a weather underground 968 station in a windy place that's got rapidfire enabled and watch it for a while and see how the updates actually are.

[bippen]

Slow Modem....that would answer my question, great idea!

Bushman....yeah, I don't need continuous wind.  My confusion here is differntiating between sampling and transmission intervals on these stations.  Is the 14 seconds just the transmission interval or is it the actual sampling interval as well.  Does the unit gather data every second and send a packet to the console every 14?  Or is 1 sample collected and sent every 14 seconds and I'll never see anything in between in the downloaded data?

I'm going to find a 968 on weather underground and see what the data looks like.

Again, pardon my ignorance on this stuff and I appreciate the feedback....I'm a computer guy and tend to make stuff more complicated than it really is!

[Bushman]

I can tell you that my Davis samples and reports wind every 2.5 to three seconds.  So if you had a real time sniffer on the data you would only see a reading every 2-3 seconds.  I suspect the OS is every 14 seconds.  BICBW.  I have a Kestrel  hand held unit that shows real time wind in continous  mode.

[sam2004gp]

I am a WMR968 with some wind and my rapid fire is on my site.

[Bushman]

Hey Bippen - found a solution for your wind problem.    http://www.inspeed.com/wind_data_logging/Windware_Wind_Speed_Data_kit.asp  Under a hundred bucks for realtime!  Needs a PC though.

[bippen]

Hey Bushman, I came across that inspeed unit while search on this stuff the other day, it's a pretty small world when you're noodling on this type of stuff.   

Nice site / station you have Sam2004gp.....and I especially like the elephant avatar!

I think I may be experiencing the usual 'make it more complicated than it is' situation I often get myself into.  My whole thing with all of this is that I'm concerned I'll miss a day's ACTUAL highest wind gust because it didn't occur on one of the sampling events at a 14 second point.  However I just realized that these units most likely keep track of the highest wind speed BETWEEN transmissions and send it along during a transmission to keep the gust data accurate.

Does that sound right?

[sam2004gp]

On the OSWMR968, the "high wind speed" is the highest "wind speed" pulled on the normal 14 sec sample intervals.  So if you miss the "true" high wind speed in between the 14 sec, then you miss it.   

[bippen]

Thanks Sam, that is what I needed to know...I might've led everyone a round-about way of getting there, but we're there.

The 968 looks to be my station of choice with the requirements I have.

I'll be sure to keep everyone posted as I purchase and set it up.  I'll also let you know if I learn anything else regarding this topic.

Kevin.

[sam2004gp]

No problem, always around to help.

[SlowModem]

Hey Sam,  he hasn't gotten around to the  "s" word yet.

[bippen]

Hmmmm, the dictionary is awfully big....s, um..........

[SlowModem]

I am assuming that you will want to connect your 968 to a computer.  If you do, you will need Software to analyze/store/upload your data from the 968.

 

[bippen]

Oh yeah, that word.  Thankfully for you guys (famous last words) I've got that one covered.  Might even try to write my own since that's what I do by day....but I've seen a lot of stuff that will work that's already out there.  Suggestions are of course welcome.

[SlowModem]

Oh yeah, that word.  Thankfully for you guys (famous last words) I've got that one covered.  Might even try to write my own since that's what I do by day....but I've seen a lot of stuff that will work that's already out there.  Suggestions are of course welcome.

There's lots of good programs out there.  My favorite word is FREE.  Of course, I don't do as much with my data as other people here.  But FREE is a good word to keep in mind.   

[bippen]

Oh yeah, FREE is good, already found a few on CWOP.  Now if I could only build telescopes for FREE......

[SlowModem]

I don't know if this will come to pass or not.  But, the NWS has posted high wind warnings for my area tomorrow.  I suppose my anemometers will be tested, but it will be a good comparison between the 2315 and the 968.

From the NWS:

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST TENNESSEE...SOUTHWEST
VIRGINIA AND EXTREME SOUTHWEST NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT

A LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE OHIO RIVER VALLEY
TONIGHT...WITH WINDS INCREASING ACROSS THE MOUNTAINS AFTER MIDNIGHT.
DAMAGING HIGH WINDS WILL BE POSSIBLE IN THE FOOTHILLS OF THE SMOKY
MOUNTAINS TOWARDS SUNRISE...WHERE A HIGH WIND WARNING IS IN EFFECT.

FOR FURTHER DETAILS ABOUT THESE HIGH WINDS...PLEASE SEE MEMNPWMRX.


.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THESE HIGH WINDS AROUND THE MOUNTAINS AND THEIR IMMEDIATE FOOTHILLS
WILL CONTINUE THROUGH FRIDAY AFTERNOON...AS A COLD FRONT SLOWLY
APPROACHES THE REGION.

[sam2004gp]

Hey Sam,  he hasn't gotten around to the  "s" word yet.

MMMmmmmmmm, awe Yes, the "S" word. 

[SlowModem]

I know as soon as I post this the wind will probably die, but we've been having pretty good wind this afternoon and if you're still wondering about the update rate, you can see it here.

[fritz_monroe]

I hate bringing up older threads, but have a couple questions for you guys. 

I'm shopping for my first weather station.  I've been leaning towards the Davis units, but the WMR968 is about half the price, and that's a good thing.  But does the WMR968 require an additional piece of hardware like the Davis units do?  I plan on using some of the Linux software out there, so don't really want to purchase software to be able to connect it to the computer.  Also, would those of you with the WMR968 recommend it as a good unit for a beginner to purchase?  Is it upgradeable?

Thanks in advance.