Author Topic: Which barometer would you get and why...  (Read 782 times)

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Offline WX4GPS

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Which barometer would you get and why...
« on: January 22, 2018, 01:17:32 AM »
I am wondering if anyone has looked closely at these two digital barometers and which one you think is the better quality and feature set that is more important to you...


DBX2 HIGH PRECISION DIGITAL BAROGRAPH     http://www.digitalbarograph.com  $599
High precision Bosch Pressure Transducer Accuracy 0.25 mb/hPa
Supports multiple units of measure: mb, inHg, mmHg, psi, h20, atm, pas, includes a one Day Graph and a one Week Graph, Ability to display multiple formats at once
Audible and visual alerts and warnings.
Display Sea, local and User definable pressures
Nist Test Certificate


Mintaka Duo Sensor Digital Barometer      http://www.weems-plath.com/Mintaka.html   $595

Two independent, high-precision atmospheric pressure sensors
Pressure units include: mb, hPa, kPa, in Hg, in H2O, cm H2O
Graphic pressure history display, past 30 minutes to 120 days
Choose between station or sea-level pressure display
<B>Georgetown, KY Weather Station</B><P>
Campbell Scientific CR1000 with Thermometris PRT / HMP35C/LI200X/RM Young 05305/ PTB101B/TB4 // HOBO Weather Station / Davis VP 2 FARS / Peet Bros U-100 / Davis Vantage Vue / Texas Weather Report WR-25 / Heath ID-5001 / Heath ID-4001 / Rainwise WindLog / NovaLynx 8"  SRG / 4" CoCoRaHS (KY-SC-1)

Offline openvista

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Re: Which barometer would you get and why...
« Reply #1 on: January 22, 2018, 08:16:44 AM »
I have the DBX2, and I like it.

With it, I am confident that the airport is, indeed, off, not me. CWOP agrees (http://weather.gladstonefamily.net/site/search?site=KSAW&Get%20information=Get%20information;). However, as you may know, that's certainly not gospel truth. So the DBX2 confirmation is essential to knowing who to trust.

One thing to note is that currently, although this may have changed since I got mine a few months ago, there is no battery power should the AC fail. I was told by ASI that a battery option would be forthcoming. Until then, if you unplug it, you lose all your history graphs and have to set the elevation & preferences again as they aren't stored in non-volatile memory. To keep from having to go through that, I hooked mine up to my battery backup unit.

6 months ago, when the airport had accurate pressure readings, I took my various iDevices down there to see which ones were closest to the truth. My wife's iPad Pro was virtually dead on. Turns out, that's the one closest in readings to the DBX2. Closer, in fact, than either my Davis VP2 (+1.2mb) or Vue console (-0.4mb).
« Last Edit: January 22, 2018, 08:21:15 AM by openvista »
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Offline openvista

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Re: Which barometer would you get and why...
« Reply #2 on: January 22, 2018, 08:18:57 AM »
I should also say that I received very good service from Chris @ ASI before and after the sale.
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Offline ValentineWeather

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Re: Which barometer would you get and why...
« Reply #3 on: January 22, 2018, 12:59:56 PM »
The airport and CWOP use altimeter does the DBX2 unit have options to pick altimeter? Looks like it does if altimeter is what they call local pressure. Quote: Display Sea, local and User definable pressures
Randy

Offline openvista

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Re: Which barometer would you get and why...
« Reply #4 on: January 22, 2018, 01:04:41 PM »
The airport and CWOP use altimeter does the DBX2 unit have options to pick altimeter? Looks like it does if altimeter is what they call local pressure. Quote: Display Sea, local and User definable pressures

Local pressure = station pressure (a.k.a. raw atmopsheric pressure).

Sea level pressure = altimeter

User defined pressure currently is the same as local pressure but, according to ASI, forthcoming firmware options should distinguish this from the others.
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Offline openvista

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Re: Which barometer would you get and why...
« Reply #5 on: January 22, 2018, 01:06:39 PM »
I should also point out that the DBX2 has been officially released for less than 2 months (announced Nov 30). I got mine when it was still in beta testing in September. It's been rock solid.
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Offline ValentineWeather

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Re: Which barometer would you get and why...
« Reply #6 on: January 22, 2018, 01:11:28 PM »
 Nope, Sea level pressure isn't altimeter. Maybe that's the issue this barometer doesn't do altimeter. The exact problem with the VP2 it doesn't do altimeter either but the Vue console does.
« Last Edit: January 22, 2018, 01:13:45 PM by ValentineWeather »
Randy

Offline openvista

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Re: Which barometer would you get and why...
« Reply #7 on: January 22, 2018, 01:16:42 PM »
Nope, Sea level pressure isn't altimeter. Maybe that's the issue this barometer doesn't do altimeter.

No, I mean they call altimeter "sea level pressure". I can say with 100% certainty they are using altimeter. They even have the formula in the manual. It's the ASOS 1 formula. It's the same formula that the Vue console uses.

In fairness, most barograph manufacturers (as well as iPhone app developers) refer to altimeter as "sea level pressure". Technically, altimeter is the current atmospheric pressure reduced to sea level, except it uses standard atmospheric conditions (ISA) rather than actual atmospheric conditions to calculate the reduction.
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Offline CW2274

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Re: Which barometer would you get and why...
« Reply #8 on: January 22, 2018, 03:04:59 PM »
Nope, Sea level pressure isn't altimeter. Maybe that's the issue this barometer doesn't do altimeter.

No, I mean they call altimeter "sea level pressure".
Well they'd be wrong, they're not the same. For instance my SLP earlier was 30.35", my altimeter 30.26". That's significant.

This is from the NWS:

ALTIMETER SETTING: This is the pressure reading most commonly heard in radio and television broadcasts. It is not the true barometric pressure at a station. Instead it is the pressure "reduced" to mean sea level using the temperature profile of the "standard" atmosphere, which is representative of average conditions over the United States at 40 degrees north latitude. The altimeter setting is the pressure value to which an aircraft altimeter scale is set so that it will indicate the altitude (above mean sea level) of the aircraft on the ground at the location for which the pressure value was determined. The altimeter setting is an attempt to remove elevation effects from pressure readings using "standard" conditions.

MEAN SEA LEVEL PRESSURE: This is the pressure reading most commonly used by meteorologists to track weather systems at the surface. Like altimeter setting, it is a "reduced" pressure which uses observed conditions rather than "standard" conditions to remove the effects of elevation from pressure readings. This reduction estimates the pressure that would exist at sea level at a point directly below the station using a temperature profile based on temperatures that actually exist at the station. In practice the temperature used in the reduction is a mean temperature for the preceding twelve hours. Mean sea level pressure should be used with caution at high elevations as temperatures can have a very profound effect on the reduced pressures, sometimes giving rise to fictitious pressure patterns and anomalous mean sea level pressure values.

Offline openvista

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Re: Which barometer would you get and why...
« Reply #9 on: January 22, 2018, 04:11:11 PM »
Nope, Sea level pressure isn't altimeter. Maybe that's the issue this barometer doesn't do altimeter.

No, I mean they call altimeter "sea level pressure".
Well they'd be wrong, they're not the same. For instance my SLP earlier was 30.35", my altimeter 30.26". That's significant.

Look, I get it. MSLP or "SLP", as NOAA sometimes employs the term, is not the same as altimeter (example: http://www.wrh.noaa.gov/mesowest/timeseries.php?sid=E7933&num=48). Aviation refers to it as either QFF or QNH. My point is that different communities, for instance mariners who depend on barographs in closed cabins, refer to sea-level pressure differently with varying degrees of precision. It results in a lot of confusion.

Bottom line is this: how would a digital barograph intended for indoor usage that lacks external sensors calculate MSLP? It couldn't. So the only sea-level reduction method available would be altimeter.
« Last Edit: January 22, 2018, 04:17:13 PM by openvista »
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Offline CW2274

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Re: Which barometer would you get and why...
« Reply #10 on: January 22, 2018, 04:34:20 PM »
Yes, it's very confusing. I use the altimeter merely so I can be on a level playing field with what the rest of the country uses for public consumption, nothing more, nothing less.

Offline CW2274

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Re: Which barometer would you get and why...
« Reply #11 on: January 22, 2018, 05:20:02 PM »
Here's a perfect example why I use the altimeter; when the cold front barreled through a couple of days ago, I could tell pretty much down to the minute when it happen as the subsequent pressure took off and accompaniment wind shift. The two ASOS's 8 miles SE of me, had not. Within minutes, I could tell at a glance, they followed suit. Is it life and death stuff, no, but it is fun, at least for me.

Offline openvista

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Re: Which barometer would you get and why...
« Reply #12 on: January 22, 2018, 05:33:33 PM »
Here's a perfect example why I use the altimeter; when the cold front barreled through a couple of days ago, I could tell pretty much down to the minute when it happen as the subsequent pressure took off and accompaniment wind shift. The two ASOS's 8 miles SE of me, had not. Within minutes, I could tell at a glance, they followed suit. Is it life and death stuff, no, but it is fun, at least for me.

The DBX2 sensor is VERY sensitive. It reads to the thousandth of an inch of mercury or hundredth of a millibar. It's almost always in motion, even when the Davis console pressure trend reads "steady".
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Offline CW2274

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Re: Which barometer would you get and why...
« Reply #13 on: January 22, 2018, 05:39:20 PM »
Here's a perfect example why I use the altimeter; when the cold front barreled through a couple of days ago, I could tell pretty much down to the minute when it happen as the subsequent pressure took off and accompaniment wind shift. The two ASOS's 8 miles SE of me, had not. Within minutes, I could tell at a glance, they followed suit. Is it life and death stuff, no, but it is fun, at least for me.

The DBX2 sensor is VERY sensitive. It reads to the thousandth of an inch of mercury
So does WL. Is the Vue as accurate or responsive, surely not, but it is as precise.

Offline jas340

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Re: Which barometer would you get and why...
« Reply #14 on: April 23, 2018, 03:12:53 AM »
An excellent digital barometer for a reasonable price.  http://www.dracal.com/store/products/usb_bar20/index.php

A comparison with much more expensive units:  https://www.analogweather.com/-accuracy-of-digital-barometers.html

Offline Old Tele man

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Re: Which barometer would you get and why...
« Reply #15 on: April 23, 2018, 05:54:44 PM »
Would really HELP if everybody used the SAME words/terminologies for parameters!

QFE = Raw = STA = Local
QNH = ALT = Altimeter
QFF = SLP = Sea Level

QFF ≈ (QNH = QFE*(ISA elevation correction))
« Last Edit: April 23, 2018, 06:05:25 PM by Old Tele man »
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