Thanks Pete, I have a Jupiter-T hooked up right now and wanted to see how the plot compares to your, unfortunately my antenna position is poor, so will be interesting. How many hours did you plot for? -=Bryan=- ________________________________ From: time-nuts <time-nuts-bounces+bpl521=outlook.com@febo.com> on behalf of Peter Reilley <preilley_454@comcast.net> Sent: January 7, 2017 1:15 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Survey plot as art. You start a precision survey with this command; sp You are offered 48 (hour) survey as an option. I think that you can go up to 96 hours. During the survey the scatter plot is displayed. Pete. On 1/7/2017 3:32 PM, Bryan _ wrote: > How do you display the survey plot in LH? i.e. the keyboard commands > > > -=Bryan=- > > > ________________________________ > From: time-nuts <time-nuts-bounces@febo.com> on behalf of Peter Reilley <preilley_454@comcast.net> > Sent: January 7, 2017 9:54 AM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Survey plot as art. > > > This is the survey from my Trimble NTBW50AA. It looks like some > bacteria floating around. > > The curious thing are the excursions. Rather than being noise like, > some follow a distinct > path. But this is only over a few seconds so it seems unlikely that > they are caused by > weather conditions. The survey from my Resolution T taken at the same > time and using > the same antenna (with a splitter) shows much less orderly excursions > and is more noise > like. > > > Trimble NTBW50AA survey. > > > Resolution T survey > > > Pete. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > www.febo.com<http://www.febo.com> American Febo Enterprises<http://www.febo.com/> www.febo.com Welcome to American Febo Enterprises! Welcome to American Febo Enterprises, a proud subsidiary of International MultiGeek. AFE is an intergalactic consultatorium ... > time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > > > > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... and follow the instructions there.

    Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin

Yo Peter! On Sat, 7 Jan 2017 16:31:25 -0500 Peter Reilley <preilley_454@comcast.net> wrote: > In my case (the original post) there can be no multipath difference, > same antenna and done at the same time. There sure can be. The GPS birds are moving in orbit. At certain points in the sky their signal may be bouncing off a nearby steel building and into your antenna. RGDS GARY --------------------------------------------------------------------------- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 gem@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin

     Veritas liberabit vos. -- Quid est veritas?
 "If you can’t measure it, you can’t improve it." - Lord Kelvin

Another thought, perhaps the difference is between the quality of the oscillators. The Resolution T has an ordinary XO while the NTBW50AA has an OCXO (possibly defective). I would expect the XO to be noise like in a stable temperature environment. The OCXO, if defective, may have semi-controlled excursions from it's design frequency. However, I don't know if the 10 MHz of the OXCO is used by the GPS chip and could therefore affect the calculated position. Pete. On 1/7/2017 4:31 PM, Peter Reilley wrote: > In my case (the original post) there can be no multipath difference, > same antenna and done at the same time. > The length of the cables from the amplified splitter are about the > same; within inches. > This must be some difference in the receiver, perhaps in the math? > > Pete. > > On 1/7/2017 4:16 PM, Bob Camp wrote: >> Hi >> >> In terms of multipath at GPS frequencies, a couple of inches is a >> *lot*. Also unless you have >> pretty good antennas (as in much larger than 1” each) they will have >> phase issues unique >> to each antenna. Phase cancellation and addition is what gives you >> multipath. >> >> Bob >> >>> On Jan 7, 2017, at 4:00 PM, Gary E. Miller <gem@rellim.com> wrote: >>> >>> Yo Bob! >>> >>> On Sat, 7 Jan 2017 15:16:34 -0500 >>> Bob Camp <kb8tq@n1k.org> wrote: >>> >>>> The “simple” answer is that the weird legs going out from the central >>>> blob are the result of multi-path / reflections in the received >>>> signal. With enough data you might be able to correlate them to >>>> observed obstructions. >>> I have lots of data from GPS with the antennas mounted 1 inch apart. >>> They show different weird legs, so I suspect that local >>> geology/architecture >>> is not the whole story. >>> >>> For example, compare the plot I just sent, to the one attached here. >>> Two GPS right next to each other, very differently looking plots. >>> >>> I'll admit to never generating plots over the same time interval, I'll >>> start a 24 hour test of two GPS right now. >>> >>> RGDS >>> GARY >>> --------------------------------------------------------------------------- >>> >>> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 >>> gem@rellim.com Tel:+1 541 382 8588 >>> >>> Veritas liberabit vos. -- Quid est veritas? >>> "If you can’t measure it, you can’t improve it." - Lord Kelvin >>> <uputronics.png>_______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

The plots that I posted were of a 48 hour survey but only 32% of the survey had completed. When the survey completes the plot display will disappear. Pete. On 1/7/2017 4:34 PM, Bryan _ wrote: > Thanks Pete, I have a Jupiter-T hooked up right now and wanted to see how the plot compares to your, unfortunately my antenna position is poor, so will be interesting. How many hours did you plot for? > > > -=Bryan=- > > > ________________________________ > From: time-nuts <time-nuts-bounces+bpl521=outlook.com@febo.com> on behalf of Peter Reilley <preilley_454@comcast.net> > Sent: January 7, 2017 1:15 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Survey plot as art. > > You start a precision survey with this command; > sp > You are offered 48 (hour) survey as an option. I think that you can go > up to 96 hours. > During the survey the scatter plot is displayed. > > Pete. > > > > On 1/7/2017 3:32 PM, Bryan _ wrote: >> How do you display the survey plot in LH? i.e. the keyboard commands >> >> >> -=Bryan=- >> >> >> ________________________________ >> From: time-nuts <time-nuts-bounces@febo.com> on behalf of Peter Reilley <preilley_454@comcast.net> >> Sent: January 7, 2017 9:54 AM >> To: Discussion of precise time and frequency measurement >> Subject: [time-nuts] Survey plot as art. >> >> >> This is the survey from my Trimble NTBW50AA. It looks like some >> bacteria floating around. >> >> The curious thing are the excursions. Rather than being noise like, >> some follow a distinct >> path. But this is only over a few seconds so it seems unlikely that >> they are caused by >> weather conditions. The survey from my Resolution T taken at the same >> time and using >> the same antenna (with a splitter) shows much less orderly excursions >> and is more noise >> like. >> >> >> Trimble NTBW50AA survey. >> >> >> Resolution T survey >> >> >> Pete. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > www.febo.com > time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > > > >> time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > www.febo.com > time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > > > >> www.febo.com<http://www.febo.com> > American Febo Enterprises<http://www.febo.com/> > www.febo.com > Welcome to American Febo Enterprises! Welcome to American Febo Enterprises, a proud subsidiary of International MultiGeek. AFE is an intergalactic consultatorium ... > > > >> time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... >> >> >> >> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > www.febo.com > time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > > > >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> > www.febo.com > time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... > > > > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. >

    Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin

Hi There is a *lot* of difference between how various receiver architectures respond to multipath. You can spend hours of “quality time” looking into the various claims of people having completely eliminated muitipath by this or that software trick. Bob > On Jan 7, 2017, at 4:31 PM, Peter Reilley <preilley_454@comcast.net> wrote: > > In my case (the original post) there can be no multipath difference, same antenna and done at the same time. > The length of the cables from the amplified splitter are about the same; within inches. > This must be some difference in the receiver, perhaps in the math? > > Pete. > > On 1/7/2017 4:16 PM, Bob Camp wrote: >> Hi >> >> In terms of multipath at GPS frequencies, a couple of inches is a *lot*. Also unless you have >> pretty good antennas (as in much larger than 1” each) they will have phase issues unique >> to each antenna. Phase cancellation and addition is what gives you multipath. >> >> Bob >> >>> On Jan 7, 2017, at 4:00 PM, Gary E. Miller <gem@rellim.com> wrote: >>> >>> Yo Bob! >>> >>> On Sat, 7 Jan 2017 15:16:34 -0500 >>> Bob Camp <kb8tq@n1k.org> wrote: >>> >>>> The “simple” answer is that the weird legs going out from the central >>>> blob are the result of multi-path / reflections in the received >>>> signal. With enough data you might be able to correlate them to >>>> observed obstructions. >>> I have lots of data from GPS with the antennas mounted 1 inch apart. >>> They show different weird legs, so I suspect that local geology/architecture >>> is not the whole story. >>> >>> For example, compare the plot I just sent, to the one attached here. >>> Two GPS right next to each other, very differently looking plots. >>> >>> I'll admit to never generating plots over the same time interval, I'll >>> start a 24 hour test of two GPS right now. >>> >>> RGDS >>> GARY >>> --------------------------------------------------------------------------- >>> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 >>> gem@rellim.com Tel:+1 541 382 8588 >>> >>> Veritas liberabit vos. -- Quid est veritas? >>> "If you can’t measure it, you can’t improve it." - Lord Kelvin >>> <uputronics.png>_______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

On Sat, Jan 7, 2017 at 12:54 PM, Peter Reilley <preilley_454@comcast.net> wrote: > > This is the survey from my Trimble NTBW50AA. It looks like some bacteria > floating around. Relatedly, and just for fun, here's a video I made several years ago from a few days worth of constellation status data out of a cheap SiRF receiver. It's interesting to see how the satellite geometry changes over time... or maybe it's just fun to watch the pretty colors. If you're observant you can also get an idea for where the tall trees were at my old apartment and maybe my approximate latitude. The projection is stereographic from the nadir (I think), with 90° elevation at the center, 0° elevation at the edges, and north up. The "wiggles" near the edges are due to the granularity of the positions from the receiver (half-degree, IIRC). Points are drawn with size and brightness proportional to the log signal strength, and the trails fade out exponentially. Andrew

On Sun, Jan 15, 2017 at 6:23 AM, Andrew Rodland <andrew@cleverdomain.org> wrote: > Relatedly, and just for fun, here's a video I made several years ago > from a few days worth of constellation status data out of a cheap SiRF > receiver. It's interesting to see how the satellite geometry changes > over time... or maybe it's just fun to watch the pretty colors. If > you're observant you can also get an idea for where the tall trees > were at my old apartment and maybe my approximate latitude. > > The projection is stereographic from the nadir (I think), with 90° > elevation at the center, 0° elevation at the edges, and north up. The > "wiggles" near the edges are due to the granularity of the positions > from the receiver (half-degree, IIRC). Points are drawn with size and > brightness proportional to the log signal strength, and the trails > fade out exponentially. > And here is the actual video: https://www.youtube.com/watch?v=VZHK1c54YRk -- sorry about the suspense. Andrew