Barometer reading inaccurate

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My 01536CDI's barometer has never worked properly for me, it's been way off compared to neighboring stations, despite making corrections, resetting, etc.  One thing that is something I had hoped would resolve itself is it shows a sawtooth pattern, swings you can notice on the Acurite page or on my WU page (KNYVALLE2).  Is this fixable?  I wish I had found this forum much sooner - thanks in advance!
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Jim M.

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Posted 3 months ago

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Jim M.

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Anyone?  I've never had a barometer that behaved like this, especially with that sawtooth swings.  This is not my first personal wx station, I've used lacrosse stations before, but gave up on them due to rf interference issues from a amateur radio station.  I'm not thinking of upgrading unless someone can point a way to dealing with the barometer swings...
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Jim M.

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Anyone?
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Jack Canavera

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Not sure what you consider as accurate.  Obviously there are various means of displaying your barometer pressure.  One is a pressure adjusted for sea level which in many cases is what the local weather bureaus use, another is station pressure which is the actual pressure reads at your location. Your 01536 is using station pressure which then is adjusted by an Acurite algorithm.  Typically when you first power up your display the pressure is adjusted by that algorithm for a period of 15 days before it becomes relatively acurite.  However that adjustment process will continue to occur over a 30 day period.  I currently have multiple Acurite display units in my home, including a 01536.  I find that they all have their difference in reporting rate of changes.  For example the 01536 display and my Atlas displays during periods of stable pressure will remain within .02 hg.  the 01536 seems to show changes in barometric pressure more rapidly than the Atlas units and a simple temperature/humidity display Acurite unit with a barometer built in show the changes the fastest.  So right now that unit in a rising barometer environment is reading 29.95 with the 01536 29.89, one Atlas display is 29.97, and the other Atlas display is 29.95.  All show a rising pressure except for the last Atlas which is showing steady.  But again all the displays show variances during times of change.  Compound that by the NOAA weather station at the St. Louis airport which shows 30.03 about 40 minutes ago under a rising barometer.  They are about 30 miles NE of me about 70 feet higher in elevation.  Their readings are adjusted to sea level.  

So bottom line not sure what "saw tooth" is to you because to me it would depend upon the granularity of the length of time you would be graphing for example and the number of samples within that time period.  Technically I have much more granularity than the local weather bureau  so I would expect my saw teeth to be a lot smaller.  Secondly the locale in which you live in has a lot to do with the rate of change.  Right now in the midwest in spring, we see a lot of the low and high pressure centers traveling closer to us, again giving us much more barometric pressure variances.

You also have another can of worms when if you have a SmartHUB or Access reporting to the MyAcurite site since those devices can report station or actual pressure or adjusted pressure where AcuRite uses altitude adjustments for your locale.  Since I have both devices I use station pressure with each along with a calibration factor which allows the MyAcurite site to stay within lockstep of my displays.  
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Jim M.

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Wish I had caught this sooner, my email notification didn't work.  This is my first accurite station, I've had several Lacrosses in the past which I used to use in the CWOP network.  However while this one has not had the issues I've had in the past, the barometer would never past muster with MADIS so I've been out of network since I've used this.   All I know is I can't get the barometer close to what I have with my other ones (old school analog, previous wx station)  I have tried calibrating once and waiting the two weeks, repeating the process with and without checking the calibration box in the pressure (acurite pc connect dialog) and I've not been even close, trending with the real pressure or not.  I don't know if my barometer is simply broken, or it's being thrown off by the algorithm.  Below is my reading for this afternoon, and then a neighboring station using an old Davis.  His pressure parallels what is broadcast by JFK airport 5 miles away. 
That's actually pretty smooth for me, normally it's just a jagged up and down wave.  This is more apparent on the WU if you look at the weekly reading https://www.wunderground.com/personal-weather-station/dashboard?ID=KNYVALLE2

I'm looking to see if there's a way to disable the algorithm and see what the actual barometer is.  If not, then I'll go looking for another weather station and politely tell Acurite to stop sending me the upgrade notices.  It would've been nice if one of their techs had responded, but I do appreciate you getting back to me - many thanks!!
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Jack Canavera

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Here's a little more info regarding the 01536 and PC-Connect that you are using.  Note that the display screen you are looking at is showing you adjusted pressure using Acurite's algorithm.  I don't believe you can override that.  Check out page 20 and 21 of your display manual for instructions on how to calibrate the barometric pressure on the display screen.  If you haven't tried that.  Critical in this however is that for the first 30 days that pressure will not be stable until you get through that learning period.  Then you make your adjustments after that time frame.  

Be aware that the PC-Connect software, has an two options available to use adjusted pressure or the raw station pressure unaltered and sends that info to AcuRite and Weather Underground.  That station pressure however can be altered using the calibration field that is part of the PC-Connect software.  So make sure you are set for station pressure.  Then it should be a matter of determining what you want to  adjust it by, using the PC-Connect adjustment factor to get it in sync with the surrounding stations in your area.  https://kbase.myacurite.com/web/content/devices/set-pressure-calibration.htm  No need to wait for a calibration function on the PC-Connect side.
(Edited)
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George D. Nincehelser

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Jack is correct.  The only thing the "learning method" affects is the reading on the display screen.  It has no impact on what is transmitted to myAcurite and wunderground.

I'd do a full hard-reset on the console and remove any calibrations you've done in either myAcurite or PC Connect.

Then re-calibrate within the PC Connect software to an altimeter pressure reading you know is correct.  Ignore what is on the display screen for at least two weeks.

If the trends still don't match well, then there's probably something wrong with the baro sensor inside the display.
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Jim M.

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Thanks Gents!  Did the hard reset and calibrated to JFK airport.  Hopefully in 2 weeks it will work, or at least parallel the neighbors!