* On 2021 12 Jan 13:40 -0600, galfert wrote: > Stop saying that the airport is at the same elevation or at different > elevation from you. That is extraneous and irrelevant information.
I am merely attempting to be factual as I'll admit to being still a bit confused as to what unit the METAR from my airport shows, whether barometer or altimeter. No matter, I shall not concern myself with that any longer. > Use this sight to find out your elevation: > https://www.freemaptools.com/elevation-finder.htm I think Google Earth is better for this purpose as the satellite view lets me pinpoint my house exactly. This site has not such view that I've seen and there is a hill side from the west around to the east and even being 100 yards off can mean a difference of 20 to 40 feet, maybe more, of elevation. > If you don't have the latest firmware then you may not have Loop2 data. Not > having Loop2 data will inhibit greater Altimeter calculation by WeeWX > because station pressure will be missing and it will have to work backwards > and that is less accurate. Better to send the software station pressure > which is done by having Loop2 data. According to the Davis site the latest firmward for the Vantage Pro2 is 3.15 and wee_device reports my console is at 3.15. I have not specified which LOOP data WeeWX is to use as I assume it is coded to use the best available format. > Do not attempt to constantly calibrate your station with the airport. It is > perfectly normal for there to be times when your pressure and the airport > are experiencing different pressures, meaning you'd both be right by each > showing what is occurring at each location. If you want to know why then > study isobars. I wrote this little piece which might introduce the subject, > but I think you should read more about it to fully grasp the concepts. > https://www.wxforum.net/index.php?topic=36579.0 I set the Correction Constant to 0 last night with wee_device and right now the airport shows 30.08 and my station is at 30.09. However, there is a falling tendency right now. I plan to leave things as they are and let it run for some time with no correction. > There are also other reasons than isobars when the pressure could be > different between your location and the airport and that has to do with > differences in equipment and how pressure is calculated internally by the > hardware. Different times of the year when the average temperature is at > extremes will also cause for more discrepancies. Therefore the best time to > calibrate your barometer is when: > > > - when the METAR indicates the pressure is very near 1013.25 hPa > - at the top of the hour when METAR data is most current > - when the pressure is steady > - when it is midday > - when it is good weather > - when the temperature *outside* is close to 15°C (least critical) Thanks. - Nate -- "The optimist proclaims that we live in the best of all possible worlds. The pessimist fears this is true." Web: https://www.n0nb.us Projects: https://github.com/N0NB GPG fingerprint: 82D6 4F6B 0E67 CD41 F689 BBA6 FB2C 5130 D55A 8819 -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/20210112201215.ycbmik6g3myajbab%40n0nb.us.
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