Hi The gotcha is that the GPS numbers are related to a geoid model and not to sea level. You can indeed find points that are “underwater” based on the geoid, but quite dry in real life (and vice-versa).
Bob > On May 19, 2015, at 12:26 PM, Demian Martin <[email protected]> wrote: > > I would buy that (Google Maps being off) except that I'm less than 2 miles > from the SF bay and -5M would have me underwater. That may well happen but > not for a few years at least. Also the Arbiter does match Google maps pretty > closely. It doesn't really matter a lot, just a curiosity. > Demian > >> Date: Mon, 18 May 2015 18:12:58 -0400 >> From: Bob Camp <[email protected]> >> To: Discussion of precise time and frequency measurement > <[email protected]> >> Subject: Re: [time-nuts] Thunderbolt Height Error >> Message-ID: <[email protected]> >> Content-Type: text/plain; charset=us-ascii > >> Hi > >> The simple answer is that Google maps may or may not be correct. There are a >> lot >> of examples of them being off by 10M or more. That said, my *guess* would be >> that the >> Thunderbolt is closer to the truth. > >> Bob > >> On May 18, 2015, at 2:34 AM, Demian Martin <[email protected]> wrote: >> >> I have 2 GPSDO's. A Thunderbolt and an Arbiter 1083A. The Arbiter is old but >> it works fine (and has a Wenzel 5 MHz streamline oscillator in it). It has >> the 1995 firmware issue, and I could get new firmware for it ($$) but I'm >> not using it as a clock, just a frequency source. >> >> >> >> I just moved and have re-setup both. They share an antenna. I got both to do >> a self survey. The Arbiter was really close to what Google maps indicate is >> my location. The Thunderbolt was about the same except it has me >> underground. The arbiter has the height as +30M. The Thunderbolt as -6M. >> What setting do I have wrong in the Thunderbolt? Would it affect the >> operation as a frequency standard in any way? >> >> >> >> >> >> Demian Martin >> >> San Leandro, CA 94577 > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
