----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]----
I've never really seen satisfactory altitude readings from GPS, though they're much better since Clinton shut off the built-in errors. Do I understand that WAAS is really going to help this problem? I think you need four solid satellites (as opposed to 3) to get a good altitude reading, and that more is better. If you look at your display, four is quite often the best you can do even on a 12-channel. I've noticed that my cheap Garmin GPS12 does better at altitude readings than my Lowrance 300 (even though the latter is also 12 channels). The Garmin receiver is, however, God's gift to GPS navigation. So I suppose the s/n ratio on the worst satellite on the 12 is better than it is on the Lowrance. Greg At 11:34 PM 8/7/01 -0500, John Trowbridge wrote: >----[Please read http://ercoupers.com/disclaimer.htm before following any >advice in this forum.]---- > >Anybody notice that the GPS altimeter reading and the >Kollsman reading can vary considerably (100-200 feet), >even when below 3000 MSL? >John Trowbridge >Houston >415E 94783 > >----- Original Message ----- >From: dan & ann curcio <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Sent: Tuesday, August 07, 2001 8:07 PM >Subject: Re: [COUPERS] Altimiter Adjustment ? > > > > ----[Please read http://ercoupers.com/disclaimer.htm before following any >advice in this forum.]---- > > > > Larry, > > You are correct as long as you don't intend on flying any kind of >distance from your airport. The > > problem only surfaces in the air when ATC gives you the current barometric >pressure at their airport which > > is most likely different than the airport from which you started. If you >go ahead and adjust your > > altimeter with the little knob to the new pressure using the kollsman >pressure indicator window your > > indicated altitude could be way off from actual. If you leave the knob >alone and make no adjustments your > > altitude will be off as well. How much off do you want to be on your >altitude? It probably is not to > > much of a problem in VFR conditions other being at the wrong altitude in >the traffic pattern, but having > > your altimeter showing any difference from the actual altitude in IFR >conditions could really ruin your > > day if you break out of the clouds on an approach at 200 ft. only to find >the ground 50 ft. below you. I > > regularly check my altimeter to the current altitude and pressure on the >ground not just adjust to the > > known altitude of my airport. > > > > Dan > > > > Larry Wilkins wrote: > > > > > Don't know what all this altimiter adjustment problem is. I just adjust >mine with the little knob on > > > the front of it. If I do it while on the ground, and at a known airport >altitude, it's always right > > > on. Nooo Problemooo. > > > > > > Larry > > > > > > > > > ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?aVxiLm.aVzvvT Or send an email To: [EMAIL PROTECTED] This email was sent to: [EMAIL PROTECTED] T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================
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