MJR Posted September 7, 2011 Report Share Posted September 7, 2011 I've just bought a Kestrel. I calibrated the altitude to 1100ft from the os map and the Baro pressure was showing 999.6mb. This morning its colder and damp outside - the pressure is showing 1007.1 and the altitude is showing 902ft which is obviously wrong as i haven't moved location. I suspect the pressures altered so the kestrel is miscalulating the altitude, is this right? And how do I best use the kestrel for station pressure for shooting? Thanks. Link to comment Share on other sites More sharing options...
Orka Akinse Posted September 7, 2011 Report Share Posted September 7, 2011 Don't get all bent out of shape but...Have you set up your ref data properly? It has took me a couple of goes along with searching the tinternett for a local weather station etc. It now seems to work ok. I have however just done mine and will try it tomorrow to see if there is any difference. Would there be a difference between setting up and being indoors and outdoors? ATB Link to comment Share on other sites More sharing options...
brown dog Posted September 7, 2011 Report Share Posted September 7, 2011 Chaps, Bottom line: - never ever pick up a map to input anything to your kestrel. - always have alt set to zero on the kestrel (forget maps!) - this means the kestrel reading is showing station pressure (not barometric -and that means it will not be giving the same value as the local weather forecast (which is barometric)) - always use station pressure in your ballistic program/solution Read the first three paragraphs of this article by Lindy http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Baro/ Link to comment Share on other sites More sharing options...
MJR Posted September 7, 2011 Author Report Share Posted September 7, 2011 Thanks chaps, i've read that article before and now the penny has dropped. Link to comment Share on other sites More sharing options...
Orka Akinse Posted September 7, 2011 Report Share Posted September 7, 2011 more reading! The older I get the more I just wanna do but.... Happy days Link to comment Share on other sites More sharing options...
terryh Posted September 7, 2011 Report Share Posted September 7, 2011 Find a local weather nut with better kit that you e.g. http://www.ianedwards01.co.uk/live/ go park next to his weather station with a magazine and calibrate your Kestrel (pulling up the live feed on your I phone or whatever). Make sure it's a local one then you can check the cal as you drive through! T Link to comment Share on other sites More sharing options...
andybrock Posted September 7, 2011 Report Share Posted September 7, 2011 Chaps, Bottom line: - never ever pick up a map to input anything to your kestrel. - always have alt set to zero on the kestrel (forget maps!) - this means the kestrel reading is showing station pressure (not barometric -and that means it will not be giving the same value as the local weather forecast (which is barometric)) - always use station pressure in your ballistic program/solution Read the first three paragraphs of this article by Lindy http://www.arcanamavens.com/LBSFiles/Shooting/Downloads/Baro/ BD, I've got a Kestrel 4000 that I've had for a couple of years never used it much because I could never get consistent data out of it (calibrated it as per instructions) so before I dig it out of the drawer to try it again are you saying you set alt to zero every time you switch it on or every time you get to a new shooting position to get station pressure? but then if it's set to zero how do you get accurate alt data....confuessed Thanks Andy Link to comment Share on other sites More sharing options...
brown dog Posted September 7, 2011 Report Share Posted September 7, 2011 BD, I've got a Kestrel 4000 that I've had for a couple of years never used it much because I could never get consistent data out of it (calibrated it as per instructions) so before I dig it out of the drawer to try it again are you saying you set alt to zero every time you switch it on or every time you get to a new shooting position to get station pressure? but then if it's set to zero how do you get accurate alt data....confuessed Thanks Andy Andy, To get what I'm doing you need to read the link and really zero-in on the difference between station pressure and barometric pressure. Station pressure is the genuine 'weight' of the air above you. Barometric pressure is the one weather forecasters use to make an equivalent sea-level pressure (if they didn't you'd always think you were in a low pressure system in the alps, and always in a high pressure system by the coast -and it would all get a bit meaningless). If someone tells you barometric pressure and you want to know the real 'weight' of the air above you; then they must tell you the altitude too....and from that you can work out the real 'weight'. But you can cut this step out if you alway set alt zero. If you set your kestrel to alt 0 it will tell you the actual pressure (ie station) because it's like telling it you're at sea level.....and therefore its telling the real air 'weight' not the weird weather forecaster's one. Never put in any other alt. Always set zero altitude. ....but this means you must also use your ballistic prog/solution in station too........so always input alt zero there too. Use station and never use a map for rifle ballistics again Link to comment Share on other sites More sharing options...
Orka Akinse Posted September 8, 2011 Report Share Posted September 8, 2011 I got it.... mine is now reset Cheers BD Link to comment Share on other sites More sharing options...
gunnery Posted September 8, 2011 Report Share Posted September 8, 2011 how do you 0 set altitude on a kestral 2500 anyone know Link to comment Share on other sites More sharing options...
Orka Akinse Posted September 8, 2011 Report Share Posted September 8, 2011 how do you 0 set altitude on a kestral 2500 anyone know I assume its the same on all of them or am I being silly to apply logic? If not here you go: http://www.r-p-r.co.uk/downloads/kestrel/k25_web.pdf ATB Its Para 8 on page 4 Link to comment Share on other sites More sharing options...
.jpg.0972b4e2bdf0b5a4109eb96f2b1b62ad.jpg)
(200x135).jpg.0fd0a94f065c6cb243fdff1b40e0819a.jpg)
Recommended Posts
Archived
This topic is now archived and is closed to further replies.