Greenside Posted June 25, 2009 Share Posted June 25, 2009 If anyone has a fairly reliable barometer could they please PM me so I can get a reading at some convenient time. Thanks. Link to comment Share on other sites More sharing options...
Dustoff Posted June 25, 2009 Share Posted June 25, 2009 (edited) ~ Current conditions, Chiangmai Airport Trust the guys Who fly the skies... Edited June 25, 2009 by Dustoff Link to comment Share on other sites More sharing options...
rikki Posted June 26, 2009 Share Posted June 26, 2009 ~Current conditions, Chiangmai Airport Trust the guys Who fly the skies... Can you tell me if I have to be at the same height as the airport to calibrate my altimeter/barometer using their data?? Link to comment Share on other sites More sharing options...
Dustoff Posted June 26, 2009 Share Posted June 26, 2009 ~Current conditions, Chiangmai Airport Trust the guys Who fly the skies... Can you tell me if I have to be at the same height as the airport to calibrate my altimeter/barometer using their data?? No. It doesn't matter how tall you are (height); Your elevation (i.e on a mountaintop); Your altitude (as in an aircraft).. If you are within a reasonable distance from the airport, say 50Km, the barometric pressure will be closer than you would care to question anyway. Assuming of course that you are setting an altimeter? If not, check out this link Link to comment Share on other sites More sharing options...
rikki Posted July 14, 2009 Share Posted July 14, 2009 I want to calibrate my barometer/altimeter on the gps. I believe I have to calibrate both because they are dependent on each other thanks for the link, I'll look at it. ~Current conditions, Chiangmai Airport Trust the guys Who fly the skies... Can you tell me if I have to be at the same height as the airport to calibrate my altimeter/barometer using their data?? No. It doesn't matter how tall you are (height); Your elevation (i.e on a mountaintop); Your altitude (as in an aircraft).. If you are within a reasonable distance from the airport, say 50Km, the barometric pressure will be closer than you would care to question anyway. Assuming of course that you are setting an altimeter? If not, check out this link Link to comment Share on other sites More sharing options...
Blinky Bill Posted July 14, 2009 Share Posted July 14, 2009 Your GPS altitude is calibrated on the GPS elipsoid, most likely WGS84. Link to comment Share on other sites More sharing options...
FarangFlyer Posted July 20, 2009 Share Posted July 20, 2009 Your GPS altitude is calibrated on the GPS elipsoid, most likely WGS84. Pressure decreases with altitude. So it will make a difference if you are at a significantly different altitude from the weather station where you are taking your readings from. 30ft=1mb approx (27 is usually a bit closer to the truth in the sort of atmospheric conditions that we have in Thailand). This is why barometric pressure is normally given with reference to sea-level, and it is this that you would normally want to set when calibrating. Within 30kms of the weather station, pressure should not change too much (on a calm day), unless you are around Lampang which for some reason seems to have quite different pressures from Chiang Mai (with the elevation difference removed of course). By all means use a GPS fix to obtain your altitude, depending on the satellites, it is usually accurate to 100ft (or 3mb) (WGS 84 Datum is solely for Lat/Long co-ordinate position) If you fancied an adventure, you could always take your baro to the weather office at Chiang Mai Airport and set it up from there! For more modern methods, most weather data can be displayed on your sidebar (Vista, Win 7) using the weather network gadget. Link to comment Share on other sites More sharing options...
FolkGuitar Posted July 20, 2009 Share Posted July 20, 2009 How about just going to the parking lot of the CM airport, and setting your altimeter to 340 meters (I believe that's the local height above sea level there. Better check that first. ) That should set your barometer spot on, wouldn't it? Link to comment Share on other sites More sharing options...
davidgtr Posted July 20, 2009 Share Posted July 20, 2009 Why not just go to the Met Station at the airport & get the info direct from the horses mouth in real time. The Northern Region Meteorological station N18 46.299 E98 58.158 Mahidol Road, left hand side after Customs & Immigration. There's a line on the wall with the precise altitude so you can get it right + a barometer that they will read & so give you the exact barometric pressure then & there. Link to comment Share on other sites More sharing options...
cloudhopper Posted July 20, 2009 Share Posted July 20, 2009 Why not just go to the Met Station at the airport & get the info direct from the horses mouth in real time.The Northern Region Meteorological station N18 46.299 E98 58.158 Mahidol Road, left hand side after Customs & Immigration. There's a line on the wall with the precise altitude so you can get it right + a barometer that they will read & so give you the exact barometric pressure then & there. An altimeter set to a known elevation will also automatically read out the pressure setting (which normalizes local actual pressure at that altitude to sea level pressure). This is the pressure number given out by airports but will not be the same as shown on a regular barometer located above sea level. Link to comment Share on other sites More sharing options...
Greenside Posted July 20, 2009 Author Share Posted July 20, 2009 (edited) Sadly, after all this no doubt excellent advice it looks like the lads at Heathrow, Shanghai or BKK managed to render my new barometer inoperable en route from Blighty. Anyone suggest a place to get it fixed? I doubt Amorn would even know what it was Edited July 20, 2009 by Greenside Link to comment Share on other sites More sharing options...
FarangFlyer Posted July 21, 2009 Share Posted July 21, 2009 Sadly, after all this no doubt excellent advice it looks like the lads at Heathrow, Shanghai or BKK managed to render my new barometer inoperable en route from Blighty. Anyone suggest a place to get it fixed? I doubt Amorn would even know what it was An avionics engineer should be able to sort it properly. I may be flying out of Chiang Mai middle of next week. If I find one there, I will PM you contact details. It may be that the aneroid capsules have been damaged though, in which case repair is probably not practical. Link to comment Share on other sites More sharing options...
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