If you want to get within a few feet of accuracy a device that measures barometric pressure is the only current option. A basic altimeter is needed. A Barometric Altimeter measures altitude. As noted in another post, they work off of barometric pressure. Aircraft grade equipment, although expensive, is the best option available. A Variometer is also known as a rate-of-climb indicator or a vertical speed indicator (VSI). It measures rate of climb and/or fall. A Variometer can also have an altimeter function built into it.
Here is a good link for building one, http://ludens.cl/Electron/Vario/vario.html Roger Dixon Certified Wind Site Assessor Skylands Renewable Energy, LLC 908.337.2057 cell 908.730.6474 fax roger.di...@att.net -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of penobscotso...@midmaine.com Sent: Wednesday, January 28, 2009 7:26 AM To: RE-wrenches Subject: Re: [RE-wrenches] GPS units I'll reiterate what was said earlier. I paraglide and use a variometer for measuring altitude. It uses barometric pressure and is accurate to within a few feet (cross referencing maps of launch areas). You can find used, very good quality variometers on paragliding and hang gliding sites for a couple hundred dollars or buy one new for about $400. Daryl Penobscot Solar Design > I used to have a WW II aircraft altimeter (out of an Aircobra) installed > in a Diesel LandRover when I first started pump work years ago. The > instrument took all the guesswork out of sizing pumps, and let me know > when the naturally aspirated Diesel was going to be making more smoke > than horsepower. An altimeter needs to be set every time you head out, > but they are accurate to within a few feet. Over the years, I have used > GPS, shot in elevations with transit and rod, used fine elevation topos > and guessed. :-) I agree that the only really accurate method, if > available, is to use a pressure gauge on existing plumbing, but an > altimeter is a close second and a GPS third. > > Matt T > > Jason Lombard wrote: > >> William, >> >> Topographic maps are great if your familiar with them. A laser if you >> can afford it or the best I have heard of is fill a tube or pipe with >> water from the pump to your tank and measure the psi at the base of >> it. The calculation is 2.31 feet of lift for every psi. Not everyone >> has their piping rolled out or on site yet so this could be a >> challenge and again is very accurate. >> >> BTW - GPS units are inaccurate to the extent that they are 40 feet off >> horizontally and 90 feet vertically. This means you could be up to 130 >> feet off. Big difference when your sizing for particular pump out put. >> >> Good luck, >> >> On Tue, Jan 27, 2009 at 2:34 PM, William Miller <wrmil...@charter.net >> <mailto:wrmil...@charter.net>> wrote: >> >> Does anyone have a foolproof tool to measure elevation? I have >> researched GPS units recently. They are notoriously inaccurate >> for elevation: >> >> http://wiki.motionbased.com/mb/GPS_Unit_Elevation >> >> Here are few more links with GPS fundamentals: >> >> http://www.adventurenetwork.com/cgi-bin/adventurenetwork/GPS_101.html >> http://www.gpsreview.net/electronic-compass/ >> >> I have a Suunto Observer watch with an altimeter. I think I can >> get relatively accurate measurements of DIFFERENCE in elevation if >> I measure the two elevations in quick succession. I will be >> trying it. >> >> >> >> William >> >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: RE-wrenches@lists.re-wrenches.org >> <mailto:RE-wrenches@lists.re-wrenches.org> >> >> Options & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> <http://www.re-wrenches.org/etiquette.htm> >> >> Check out participant bios: >> www.members.re-wrenches.org <http://www.members.re-wrenches.org> >> >> >> >> >> -- >> Jason Lombard >> Open Hand Solar LLC. >> Certified Sustainable Building Adviser >> openhandso...@gmail.com <mailto:openhandso...@gmail.com> >> 505 795 8646 >> >> "I'd put my money on solar energy... I hope we don't have to wait 'til >> oil and coal run out before we tackle that." >> >> --Thomas Edison >> >>------------------------------------------------------------------------ >> >>_______________________________________________ >>List sponsored by Home Power magazine >> >>List Address: RE-wrenches@lists.re-wrenches.org >> >>Options & settings: >>http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >>List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >>List rules & etiquette: >>www.re-wrenches.org/etiquette.htm >> >>Check out participant bios: >>www.members.re-wrenches.org >> >> >> >>------------------------------------------------------------------------ >> >> >>No virus found in this incoming message. >>Checked by AVG - http://www.avg.com >>Version: 8.0.176 / Virus Database: 270.10.14/1918 - Release Date: >> 1/27/2009 7:26 AM >> >> >> > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
