[time-nuts] Precise positions for GPSDOs
A GPSDO typically makes the assumption that the position of its antenna is fixed and well-known. That removes position uncertainty from the navigation equations, and allows all the information from the satellite measurements to be used to improve the time estimate. Errors in this position create errors in timing, with a magnitude scaled by the speed of light (one ns per foot, three ns per meter). Most GPSDOs do some sort of position averaging when they are first turned on, to come up with a good-enough estimate of antenna position. For a true time-nut, that might not be good enough. GPS surveying equipment can easily determine the position of your antenna to within a few centimeters (~20 ps). Unfortunately, such equipment is expensive and difficult to borrow. A high-end GPSDO designed today should have the ability to record phase data into RINEX files, which could be sent to a service like OPUS to find the antenna position. http://www.ngs.noaa.gov/opus/ But few do, so far. The next best idea is to locate your antenna on Google Maps. Type in the self-surveyed position to the Google search box, either as decimal degrees or as DMS, formatted like this but without the quote marks: 37.384542, -122.005526 37 23 4.35, -122 0 19.89 Click on the map and zoom in. Click on the Map box in the upper right and uncheck the 45 degree view icon. Then right-click on the spot on the picture where your antenna is actually located, and select What's here? from the pop-up menu. A green arrow marker will appear, pointing to your antenna. Left-click on the arrow, and read your latitude and longitude in both formats. Enter one of them into your GPSDO, replacing the self-survey, and enjoy increased accuracy. A true time-nut will take one more step to improve accuracy. (Sorry, but the rest of this is specific to North America. Similar details apply to other parts of the world, but I only know the recipe for the place I live.) Google Maps photos are registered (quite accurately) to the North American Datum NAD83. Unfortunately, your GPSDO operates in a different datum known variously as WGS84, ITRF, or IGS (these are all essentially the same). The difference between these two datums can be a couple of meters, easily visible on the map photos and worth 5 ns or more of time error. Fortunately, you can convert NAD83 to ITRF2008 at this website: http://www.geod.nrcan.gc.ca/apps/tmobs/tmobs_e.php For ITRF epoch, just enter today's date. For ellipsoidal height, use the value from your self-survey if you don't have a better one. You might be able to get a better one from Google Earth, or by finding a nearby benchmark from this site (US only) and extrapolating to your antenna location. http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl Note that the WGS84 ellipsoid is tens of meters higher than sea level through most of North America, so if you live near the ocean, your ellipsoidal height will probably be negative. Hope someone find this useful. Cheers! --Stu ___ 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.
Re: [time-nuts] three cornered comparison tools
Hi Tom,
Clear as crystal thanks. I'll post some results.
I just reread Bill Riley's notes on this, and they now also make perfect
sense.
Thanks.
david
Folks,
I asked about 3 cornered comparisons some time ago, and now have plenty
of data to start exploring, and way more than the 3 oscillators I had
when I asked six months ago.
Apart from Stable32, which I do not have access to, are there any free
tools which will allow me to perform 3 cornered comparisons between my
oscillators?
Thanks,
david
I use Excel on the { tau, ADEV } pairs when I want to get fancy, or just a
calculator for something quick. You can sometimes simply eyeball it on a
composite log-log adev plot.
I'll give the formula is below, but to understand, first consider this
backwards example:
Suppose for some tau the ADEV of three oscillators is 6e-12, 8e-12, and 10e-12,
respectively. But -- you don't know that yet -- because all you have is
pairwise measurements. The assumption is that noise is rms additive. Let's do
the numbers:
When you measure A vs. B you should get 1.00e-11, since that is sqrt( 6e-12 ^ 2
+ 8e-12 ^ 2 ).
When you measure B vs. C you should get 1.28e-11, since that is sqrt( 8e-12 ^ 2
+ 10e-12 ^ 2 ).
When you measure C vs. A you should get 1.17e-11, since that is sqrt( 10e-12 ^
2 + 6e-12 ^ 2 ).
So given your three ADEV measurement pairs (AB=1.00e-11, BC=1.28e-11,
AC=1.17e-11) you just work backwards to compute ADEV for A, B, and C, as in:
A = 0.707 * sqrt(+ AB*AB - BC*BC + AC*AC)
B = 0.707 * sqrt(+ AB*AB + BC*BC - AC*AC)
C = 0.707 * sqrt(- AB*AB + BC*BC + AC*AC)
Depending on how clean your measurement system is, and how well-behaved and
modestly different the oscillators are, the 3-hat technique can work pretty
well.
/tvb
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Re: [time-nuts] Cesium wrist-watch-lite
...if I understand what the article says, the watch won't be the demo board. So it has to be the price for thhe sheet cube itself. Am 02.05.2013 01:31, schrieb Bob Camp: Hi Rummor has it that the single piece price in the US is $1475 for just the CSAC. Weather that's with or without the demo board …. Bob On May 1, 2013, at 11:45 AM, Volker Esperail...@t-online.de wrote: Cool. Is the Symmetricom CSAC SA.45s available to mere mortals? Which price could we expect? Volker Am 01.05.2013 14:57, schrieb Poul-Henning Kamp: Looks a fair bit more comfortable than the one Tom's brother showed. http://www.theregister.co.uk/2013/05/01/hoptroff_shows_first_atomic_watch_movement/ ___ 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.
Re: [time-nuts] Cesium wrist-watch-lite
In message 5182325e.4020...@t-online.de, Volker Esper writes: Rummor has it that the single piece price in the US is $1475 for just the CSAC. Weather that's with or without the demo board And for that price a SRS PRS10 is a better buy, unless you need it to be compact and not use too much power. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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.
Re: [time-nuts] 10811
I should have given this URL: http://home.comcast.net/~rdirosario/site/?/photos/ which gives you the full resolution if you click on the photos. Robert - Original Message - From: ka3...@comcast.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, May 1, 2013 11:15:56 PM Subject: Re: [time-nuts] 10811 I just posted some photos at: http://home.comcast.net/~rdirosario/site/?/page/HP_5061-6168_photos/ - Original Message - From: John Miles jmi...@pop.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, April 30, 2013 10:53:49 PM Subject: Re: [time-nuts] 10811 Close, but it's for the 105, not the 5061, and the boards are physically very different. The 5061A upgrade used those 105-series boards. With the 5061B, they changed the part number of A1A3 (the OCXO interface board) from 00105-6044 to 05061-6198, but I don't see any major differences in the schematic, looking at the Artek .PDF manual for the 5061B. The part number on the connector for the board is the same as the connector for the 10811. Does anyone know where to get boards that fit the connector? Mouser carries the connector, but I can't find any boards. You don't really need a board -- I didn't use one (see http://www.ke5fx.com/tbolt.htm ). It uses a pretty common edge connector that can be pulled off of any number of random surplus HP PCBs, if you don't want to order one. how often do people need to retune the 10811? I have a pair of the 10811- 60109's, another 10811, and a 10544 and all are within 1 Hz of 10 MHz. That's close enough Some anecdata: my GPS-disciplined 10811-60109 has been running for about 5 years without any retuning. The DAC voltage is currently about 0.52V, and I'm sure I would have started it out near 0.0, so about 10% of its EFC control range has been needed after 5 years. (Of course it could have wandered around arbitrarily in the meantime, but I doubt it.) At -0.324 Hz/volt, this would be about 0.03 Hz per year of positive drift on average, or 3E-9 per year. That's in line with what I've seen other well-settled 10811s achieve. Is there any advantage in using the 723 voltage regulator? The 10811 and 10544 manuals both show the use of the 723 for the regulator for the oscillator supply, but on the HP schematic for the 6198 board they use a pair of three terminal regulators. HP's use of an LM317T-style regulator to drive the 18V oven supply, a 78L12 to drive the oscillator, and a Zener+emitter follower to drive the 7474 divider was a bit funky. Regulator noise on the oven supply isn't critical, but for driving the oscillator circuit itself, the difference between a 7812 and an LM317T can be seen in some cases. Not sure offhand how sensitive the 10811 is to supply noise, but you can certainly see the difference in regulators with a Wenzel ULN. In any event an LM317T would be fine for driving the +12 rail. -- john, KE5FX Miles Design LLC ___ 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.
Re: [time-nuts] Precise positions for GPSDOs
In message CAPXiX5ricf=Ea0B=c2yr8ix+70srtfj9jeutkguqehh5izb...@mail.gmail.com, Stewart Cobb writes: The next best idea is to locate your antenna on Google Maps. [...] If your GPSDO's self-survey isn't better than the registration of Google Maps, you have different problems. In particular, be aware that the GPSDO does not need to know the antennas _actual_ position, it needs the _apperant_ position, which takes the reflection environment into account. (GW: fresnel zone) This is a much better strategy: http://phk.freebsd.dk/raga/sneak/ -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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.
Re: [time-nuts] Precise positions for GPSDOs
On Thu, May 2, 2013 at 5:29 PM, Stewart Cobb stewart.c...@gmail.com wrote: GPS surveying equipment can easily determine the position of your antenna to within a few centimeters (~20 ps). Unfortunately, such equipment is expensive and difficult to borrow. A high-end GPSDO designed today should have the ability to record phase data into RINEX files, which could be sent to a service like OPUS to find the antenna position. http://www.ngs.noaa.gov/opus/ But few do, so far. There are relatively cheap single frequency GPS receivers that output raw (code and carrier phase) measurements. If you are near a base station (e.g., [1]) that provides similar measurements, you can use RTKLIB to post process both measurements and obtain a position within a few cm. A sample plot of the position of the patch antenna outside my window is attached. The receiver is a u-blox LEA-6T, the RINEX of the base station is from an IGS station 7.2 km away. [1] http://igscb.jpl.nasa.gov/network/netindex.html attachment: rtkplot.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.
Re: [time-nuts] Cesium wrist-watch-lite
On 5/2/13 5:18 AM, Poul-Henning Kamp wrote: In message 5182325e.4020...@t-online.de, Volker Esper writes: Rummor has it that the single piece price in the US is $1475 for just the CSAC. Weather that's with or without the demo board And for that price a SRS PRS10 is a better buy, unless you need it to be compact and not use too much power. A PRS10 is hardly wristwatch sized.. Unless you're the late Andre the Giant or something. The CSAC itself is pretty small (albeit thick), but I wonder if all the supporting stuff (power supply, etc.) could fit in a wristwatch. Perhaps a pendant hanging around your neck in the style of 80s rappers? http://en.wikipedia.org/wiki/Flavor_Flav ___ 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.
Re: [time-nuts] Precise positions for GPSDOs
Google maps is NOT that good, it can be off by a lot, tens of meters. I had to have my property line surveyed some years ago to get a city building permit. So now I have two brass markers at know position. The survey crew used traditional transits from a brass benchmark. Google Earth thinks these brass markers are a few meters from here the survey crew said. (Yes I know about WGS84, we are all working in that system) I think the problem is that the lland is not flat here. If I lived in Kanas the Google system might work. But I don't think Google warps the images to account for hills and even slopes. I don't know the source of Google's error. The 1 Sigma on the self survey is about .5 meters more or less. I think the best why to measure is to let the self survey run for a full 24 hours so you get two full orbital periods of each satellite. And also to make sure you have 360 degree view of the sky.I think a view in only one direction might be biased. But yu can check Google. Find a few brass government benchmarks near your house and have Google locate them and if you got a match go with Google On Thu, May 2, 2013 at 2:29 AM, Stewart Cobb stewart.c...@gmail.com wrote: A GPSDO typically makes the assumption that the position of its antenna is fixed and well-known. That removes position uncertainty from the navigation equations, and allows all the information from the satellite measurements to be used to improve the time estimate. Errors in this position create errors in timing, with a magnitude scaled by the speed of light (one ns per foot, three ns per meter). Most GPSDOs do some sort of position averaging when they are first turned on, to come up with a good-enough estimate of antenna position. For a true time-nut, that might not be good enough. GPS surveying equipment can easily determine the position of your antenna to within a few centimeters (~20 ps). Unfortunately, such equipment is expensive and difficult to borrow. A high-end GPSDO designed today should have the ability to record phase data into RINEX files, which could be sent to a service like OPUS to find the antenna position. http://www.ngs.noaa.gov/opus/ But few do, so far. The next best idea is to locate your antenna on Google Maps. Type in the self-surveyed position to the Google search box, either as decimal degrees or as DMS, formatted like this but without the quote marks: 37.384542, -122.005526 37 23 4.35, -122 0 19.89 Click on the map and zoom in. Click on the Map box in the upper right and uncheck the 45 degree view icon. Then right-click on the spot on the picture where your antenna is actually located, and select What's here? from the pop-up menu. A green arrow marker will appear, pointing to your antenna. Left-click on the arrow, and read your latitude and longitude in both formats. Enter one of them into your GPSDO, replacing the self-survey, and enjoy increased accuracy. A true time-nut will take one more step to improve accuracy. (Sorry, but the rest of this is specific to North America. Similar details apply to other parts of the world, but I only know the recipe for the place I live.) Google Maps photos are registered (quite accurately) to the North American Datum NAD83. Unfortunately, your GPSDO operates in a different datum known variously as WGS84, ITRF, or IGS (these are all essentially the same). The difference between these two datums can be a couple of meters, easily visible on the map photos and worth 5 ns or more of time error. Fortunately, you can convert NAD83 to ITRF2008 at this website: http://www.geod.nrcan.gc.ca/apps/tmobs/tmobs_e.php For ITRF epoch, just enter today's date. For ellipsoidal height, use the value from your self-survey if you don't have a better one. You might be able to get a better one from Google Earth, or by finding a nearby benchmark from this site (US only) and extrapolating to your antenna location. http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl Note that the WGS84 ellipsoid is tens of meters higher than sea level through most of North America, so if you live near the ocean, your ellipsoidal height will probably be negative. Hope someone find this useful. Cheers! --Stu ___ 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. -- Chris Albertson Redondo Beach, California ___ 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.
Re: [time-nuts] Cesium wrist-watch-lite
On 2013-05-02 14:18, Poul-Henning Kamp wrote: In message 5182325e.4020...@t-online.de, Volker Esper writes: Rummor has it that the single piece price in the US is $1475 for just the CSAC. Weather that's with or without the demo board And for that price a SRS PRS10 is a better buy, unless you need it to be compact and not use too much power. Yes, exactly. But the CSAC is marketed for a small niche, both given its price and that at least until fairly recently they couldn't (and I'm assuming still today can't) make that many. Small like (or smaller than) an OCXO, but with better stability and much lower power use. For a higher price. If one plotted ADEV/W I recon it would turn out a great performer. ADEV/USD and it wouldn't fare as well. I did go as far as asking for a quote from a Symmetricom rep. last year with a wrist watch project in mind. Put that project on the shelf when I got the quote back.:) Great to see someone with deeper pockets and more dedication made it happen! Is there any competition/alternatives for a pocketable time-nutty-stable movement? // jwalck ___ 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.
Re: [time-nuts] Precise positions for GPSDOs
I have a worse than optimal antenna location for my t-bolt and that just choked on being fed the google earth location which is 7.5 meters away. Le 2 mai 2013 à 14:22, Poul-Henning Kamp a écrit : In message CAPXiX5ricf=Ea0B=c2yr8ix+70srtfj9jeutkguqehh5izb...@mail.gmail.com, Stewart Cobb writes: The next best idea is to locate your antenna on Google Maps. [...] If your GPSDO's self-survey isn't better than the registration of Google Maps, you have different problems. In particular, be aware that the GPSDO does not need to know the antennas _actual_ position, it needs the _apperant_ position, which takes the reflection environment into account. (GW: fresnel zone) This is a much better strategy: http://phk.freebsd.dk/raga/sneak/ -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] HP 5065B!!! New A3
Hi, The New style A3 is in mainframes with SN prefix 2644A and above and has series 2644 on its label. I'll see about getting the schematic and theory page posted where everyone can access it. Corby ___ 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.
Re: [time-nuts] Cesium wrist-watch-lite
How much would it cost to design and build one to fit in a typical cell phone volume? Ronald ___ 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.
Re: [time-nuts] Precise positions for GPSDOs
Actually, wouldn't you need a satellite visible mark to use google earth? Not every marker can be seen on google earth. Then often these markers are in places you can't use safely, such as in the middle of a road. Note that google earth does orthorectification on the imagery. If you knew where the imagery had the least correction, that might be a place where the position data is accurate. If a tall structure looks tilted, then you know the image has had a lot of post processing. -Original Message- From: Chris Albertson albertson.ch...@gmail.com Sender: time-nuts-boun...@febo.com Date: Thu, 2 May 2013 08:19:17 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Precise positions for GPSDOs Google maps is NOT that good, it can be off by a lot, tens of meters. I had to have my property line surveyed some years ago to get a city building permit. So now I have two brass markers at know position. The survey crew used traditional transits from a brass benchmark. Google Earth thinks these brass markers are a few meters from here the survey crew said. (Yes I know about WGS84, we are all working in that system) I think the problem is that the lland is not flat here. If I lived in Kanas the Google system might work. But I don't think Google warps the images to account for hills and even slopes. I don't know the source of Google's error. The 1 Sigma on the self survey is about .5 meters more or less. I think the best why to measure is to let the self survey run for a full 24 hours so you get two full orbital periods of each satellite. And also to make sure you have 360 degree view of the sky.I think a view in only one direction might be biased. But yu can check Google. Find a few brass government benchmarks near your house and have Google locate them and if you got a match go with Google On Thu, May 2, 2013 at 2:29 AM, Stewart Cobb stewart.c...@gmail.com wrote: A GPSDO typically makes the assumption that the position of its antenna is fixed and well-known. That removes position uncertainty from the navigation equations, and allows all the information from the satellite measurements to be used to improve the time estimate. Errors in this position create errors in timing, with a magnitude scaled by the speed of light (one ns per foot, three ns per meter). Most GPSDOs do some sort of position averaging when they are first turned on, to come up with a good-enough estimate of antenna position. For a true time-nut, that might not be good enough. GPS surveying equipment can easily determine the position of your antenna to within a few centimeters (~20 ps). Unfortunately, such equipment is expensive and difficult to borrow. A high-end GPSDO designed today should have the ability to record phase data into RINEX files, which could be sent to a service like OPUS to find the antenna position. http://www.ngs.noaa.gov/opus/ But few do, so far. The next best idea is to locate your antenna on Google Maps. Type in the self-surveyed position to the Google search box, either as decimal degrees or as DMS, formatted like this but without the quote marks: 37.384542, -122.005526 37 23 4.35, -122 0 19.89 Click on the map and zoom in. Click on the Map box in the upper right and uncheck the 45 degree view icon. Then right-click on the spot on the picture where your antenna is actually located, and select What's here? from the pop-up menu. A green arrow marker will appear, pointing to your antenna. Left-click on the arrow, and read your latitude and longitude in both formats. Enter one of them into your GPSDO, replacing the self-survey, and enjoy increased accuracy. A true time-nut will take one more step to improve accuracy. (Sorry, but the rest of this is specific to North America. Similar details apply to other parts of the world, but I only know the recipe for the place I live.) Google Maps photos are registered (quite accurately) to the North American Datum NAD83. Unfortunately, your GPSDO operates in a different datum known variously as WGS84, ITRF, or IGS (these are all essentially the same). The difference between these two datums can be a couple of meters, easily visible on the map photos and worth 5 ns or more of time error. Fortunately, you can convert NAD83 to ITRF2008 at this website: http://www.geod.nrcan.gc.ca/apps/tmobs/tmobs_e.php For ITRF epoch, just enter today's date. For ellipsoidal height, use the value from your self-survey if you don't have a better one. You might be able to get a better one from Google Earth, or by finding a nearby benchmark from this site (US only) and extrapolating to your antenna location. http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl Note that the WGS84 ellipsoid is tens of meters higher than sea level through most of North America, so if you live near the ocean,
[time-nuts] 5V antenna on 3V receiver via dist. amp?
Is it reasonable to to use a GPS distribution amplifier (viz. HP 58516A) to power a five volt antenna feeding three volt receivers or should I get a bias tee? The internal operation of my electronics is largely a mystery to me. Thanks. -- Paul ___ 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.
Re: [time-nuts] Precise positions for GPSDOs
PHK, the big pdf link in your sneak page is broken (gives 404). Can you fix that for us? P.S., while you are there you could change goory' to gory. On 5/2/2013 5:22 AM, Poul-Henning Kamp wrote: In message CAPXiX5ricf=Ea0B=c2yr8ix+70srtfj9jeutkguqehh5izb...@mail.gmail.com, Stewart Cobb writes: The next best idea is to locate your antenna on Google Maps. [...] If your GPSDO's self-survey isn't better than the registration of Google Maps, you have different problems. In particular, be aware that the GPSDO does not need to know the antennas _actual_ position, it needs the _apperant_ position, which takes the reflection environment into account. (GW: fresnel zone) This is a much better strategy: http://phk.freebsd.dk/raga/sneak/ ___ 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.
Re: [time-nuts] time-nuts newbie
Hi A clock based on an eBay Rb can be set up to pull less than 10 watts. Based on 8 hours of light a day that would get you to 30 watts of solar needed to power it. That's a pretty small fraction of your 480W setup. You will get CSAC level timing and still fit your budget. For a lower power solution, wake up the Rb once a day around mid day. Only do it if the solar has surplus power. Re-sync your OCXO to the Rb. That should cut the power by a factor of about 10:1. A Google search for RBXO will turn up details on the process. Not quite CSAC performance, but far better than the OCXO alone. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Timothy Bastian Sent: Thursday, May 02, 2013 12:36 PM To: time-nuts@febo.com Subject: Re: [time-nuts] time-nuts newbie Wow I didn't know how much I was going to stir up here. As for the accuracy of the DS32khz you are correct in what the literature says. They call for an accuracy of one minute per year. The 10 seconds / year is what the gentleman who designed the clock thought would be possible. The testing he has done is giving better results than 10 seconds / year. My clock has not been running long enough to give you any meaningful results. As far as the requirements for my chronometer... there is what I would like to have and what I can afford. A clock driven by a csac (SA.45s) would be the ultimate. I am however shooting for something in the $500.00 or less price range. I have ships power available to power the clock but would like to have the ability to run on an internal battery for an extended period if needed. Say for two months. I have 4, 120 watt solar panels with 500 amp hours of 12 volt battery power. I'm shooting for a size of not more than one cubic foot. You are correct about the 100 ppb aging, which I believe will put me at +/- 3 seconds / year. A GPS time reference to set the clock would be acceptable however the whole point of having said clock is to still be able to navigate in the event of GPS failure. Thanks for all of the replies, Tim KK4FQB From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Wednesday, May 1, 2013 11:08 AM Subject: time-nuts Digest, Vol 106, Issue 1 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: Time nut newbie (Rex) 2. Re: 10811 (John Miles) 3. Re: HP5065B !!! (Jim Palfreyman) 4. Re: Time nut newbie (Jim Palfreyman) 5. Re: Time nut newbie (Hal Murray) 6. Re: Time nut newbie (Chris Albertson) 7. Re: Time nut newbie (Attila Kinali) 8. Re: Time nut newbie (Bob Camp) -- Message: 1 Date: Tue, 30 Apr 2013 18:57:20 -0700 From: Rex r...@sonic.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Time nut newbie Message-ID: 51807680.2040...@sonic.net Content-Type: text/plain; charset=windows-1252; format=flowed It doesn't affect the general magnitude conclusions by Bruce, but as long as we are making corrections, my calculator seems to think 60 * 60 * 24 * 12 = 1036800 seconds in 12 days, not 1024800. That does come out to 115.7 days for 1 sec error. Maybe the 12-day number was a typo? -Rex On 4/30/2013 12:57 PM, Bruce Griffiths wrote: 12 days is 1024800 s ie just over 1 million seconds so a frequency offset of 0.1ppm results in a time error of ~ 0.1s not 1s. 1sec error would occur in just under 116 days, Bruce Bob Camp wrote: Hi If you take a look down in the fine print on the OCXO spec, the aging rate is 100 ppb / year in the first year. If you are off by 0.1 ppm (100 ppb) your clock will gain a second in less than 12 days. Bob -- Message: 2 Date: Tue, 30 Apr 2013 19:53:49 -0700 From: John Miles jmi...@pop.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Subject: Re: [time-nuts] 10811 Message-ID: 004a01ce4617$1ba19710$52e4c530$@pop.net Content-Type: text/plain; charset=UTF-8 Close, but it's for the 105, not the 5061, and the boards are physically very different. The 5061A upgrade used those 105-series boards. With the 5061B, they changed the part number of A1A3 (the OCXO interface board) from 00105-6044 to 05061-6198, but I don't see any major differences in the schematic, looking at the Artek .PDF manual for the 5061B. The part number on the connector for the board is the same as the connector for the 10811.
Re: [time-nuts] Cesium wrist-watch-lite
Hi There's something over $100M invested so far getting the CSAC to it's current size. One would guess much more than that to get it (or it plus batteries) to fit in an iPhone case. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ronald Held Sent: Thursday, May 02, 2013 1:31 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Cesium wrist-watch-lite How much would it cost to design and build one to fit in a typical cell phone volume? Ronald ___ 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.
Re: [time-nuts] Cesium wrist-watch-lite
Interesting... I never even received a response from Symmetricom to my request for a quote. But I do now regularly receive their sales emails. On May 2, 2013, at 12:22, Jonatan Walck jwa...@netnod.se wrote: On 2013-05-02 14:18, Poul-Henning Kamp wrote: In message 5182325e.4020...@t-online.de, Volker Esper writes: Rummor has it that the single piece price in the US is $1475 for just the CSAC. Weather that's with or without the demo board And for that price a SRS PRS10 is a better buy, unless you need it to be compact and not use too much power. Yes, exactly. But the CSAC is marketed for a small niche, both given its price and that at least until fairly recently they couldn't (and I'm assuming still today can't) make that many. Small like (or smaller than) an OCXO, but with better stability and much lower power use. For a higher price. If one plotted ADEV/W I recon it would turn out a great performer. ADEV/USD and it wouldn't fare as well. I did go as far as asking for a quote from a Symmetricom rep. last year with a wrist watch project in mind. Put that project on the shelf when I got the quote back.:) Great to see someone with deeper pockets and more dedication made it happen! Is there any competition/alternatives for a pocketable time-nutty-stable movement? // jwalck ___ 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.
Re: [time-nuts] Cesium wrist-watch-lite
ADEV_Free_Run.pdf ADEV_CSAC_Final.pdf Said, You can update your marketing literature. My measurements of your GPSDO-CSAC are more favorable (flavorful?) than what your PDF files show. See: http://leapsecond.com/pages/csac/ /tvb - Original Message - From: saidj...@aol.com To: time-nuts@febo.com Sent: Thursday, May 02, 2013 10:46 AM Subject: Re: [time-nuts] Cesium wrist-watch-lite H jwalck, the availability of the CSAC in quantities and with short lead-times is not an issue anymore. Jackson Labs Technologies can sell CSACs and can ship from stock right now. ... ___ 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.
Re: [time-nuts] 5V antenna on 3V receiver via dist. amp?
On 05/02/2013 03:26 PM, Paul wrote: Is it reasonable to to use a GPS distribution amplifier (viz. HP 58516A) to power a five volt antenna feeding three volt receivers or should I get a bias tee? The internal operation of my electronics is largely a mystery to me. Bias tee would be best because it does exactly the thing you need and no more, so it is difficult to miss some small detail and end up in a bad configuration. Bias tees have a DC connector to supply power so it will be easier to hook up. Look for models that block DC, so you don't expose your 3V GPS receiver to 5V power. A distribution amplifier (like the 58516A) should also be OK. If you are going to have a GPS receiver that can provide 5V to the antenna and amplifier, that would be ideal. Otherwise you will need to make a connector to put 5V on the DC port of the amplifier. What you don't want is a passive splitter. If you connect a power supply directly to the DC port it will short the GPS signal into the supply's capacitance and your signal will be distorted or suppressed. ___ 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.
Re: [time-nuts] time-nuts newbie
Turning off the Rb is a good idea. That is one of the best features of the Rb is that it will come back on from a zero power and be pretty much spot on the frequency but the phase will be random.So the question is that if you want to re-calibrate the OCXO how long to you need to compare it to the Rb. You can't look at the phase difference, that has been randomized by the power cycle. I think one could get at least 10 and maybe 100 times better than the OP's requirement and still be under the $500 limit. On Thu, May 2, 2013 at 12:59 PM, Bob Camp li...@rtty.us wrote: Hi A clock based on an eBay Rb can be set up to pull less than 10 watts. Based on 8 hours of light a day that would get you to 30 watts of solar needed to power it. That's a pretty small fraction of your 480W setup. You will get CSAC level timing and still fit your budget. For a lower power solution, wake up the Rb once a day around mid day. Only do it if the solar has surplus power. Re-sync your OCXO to the Rb. That should cut the power by a factor of about 10:1. A Google search for RBXO will turn up details on the process. Not quite CSAC performance, but far better than the OCXO alone. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Timothy Bastian Sent: Thursday, May 02, 2013 12:36 PM To: time-nuts@febo.com Subject: Re: [time-nuts] time-nuts newbie Wow I didn't know how much I was going to stir up here. As for the accuracy of the DS32khz you are correct in what the literature says. They call for an accuracy of one minute per year. The 10 seconds / year is what the gentleman who designed the clock thought would be possible. The testing he has done is giving better results than 10 seconds / year. My clock has not been running long enough to give you any meaningful results. As far as the requirements for my chronometer... there is what I would like to have and what I can afford. A clock driven by a csac (SA.45s) would be the ultimate. I am however shooting for something in the $500.00 or less price range. I have ships power available to power the clock but would like to have the ability to run on an internal battery for an extended period if needed. Say for two months. I have 4, 120 watt solar panels with 500 amp hours of 12 volt battery power. I'm shooting for a size of not more than one cubic foot. You are correct about the 100 ppb aging, which I believe will put me at +/- 3 seconds / year. A GPS time reference to set the clock would be acceptable however the whole point of having said clock is to still be able to navigate in the event of GPS failure. Thanks for all of the replies, Tim KK4FQB From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Wednesday, May 1, 2013 11:08 AM Subject: time-nuts Digest, Vol 106, Issue 1 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: Time nut newbie (Rex) 2. Re: 10811 (John Miles) 3. Re: HP5065B !!! (Jim Palfreyman) 4. Re: Time nut newbie (Jim Palfreyman) 5. Re: Time nut newbie (Hal Murray) 6. Re: Time nut newbie (Chris Albertson) 7. Re: Time nut newbie (Attila Kinali) 8. Re: Time nut newbie (Bob Camp) -- Message: 1 Date: Tue, 30 Apr 2013 18:57:20 -0700 From: Rex r...@sonic.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Time nut newbie Message-ID: 51807680.2040...@sonic.net Content-Type: text/plain; charset=windows-1252; format=flowed It doesn't affect the general magnitude conclusions by Bruce, but as long as we are making corrections, my calculator seems to think 60 * 60 * 24 * 12 = 1036800 seconds in 12 days, not 1024800. That does come out to 115.7 days for 1 sec error. Maybe the 12-day number was a typo? -Rex On 4/30/2013 12:57 PM, Bruce Griffiths wrote: 12 days is 1024800 s ie just over 1 million seconds so a frequency offset of 0.1ppm results in a time error of ~ 0.1s not 1s. 1sec error would occur in just under 116 days, Bruce Bob Camp wrote: Hi If you take a look down in the fine print on the OCXO spec, the aging rate is 100 ppb / year in the first year. If you are off by 0.1 ppm (100 ppb) your clock will gain a second in less than 12 days. Bob -- Message: 2 Date: Tue, 30 Apr 2013 19:53:49 -0700 From: John Miles jmi...@pop.net To:
Re: [time-nuts] 5V antenna on 3V receiver via dist. amp?
The HP58516A has no external DC power connector (unless it has the option 05Q). The receiver feeds the HP58516A and then the antenna. Maybe your antenna works downto 3V. The bias tee needs also a DC-block, otherwise you will put the 5V to the receiver's input too. On Thu, May 2, 2013 at 9:26 PM, Paul tic-...@bodosom.net wrote: Is it reasonable to to use a GPS distribution amplifier (viz. HP 58516A) to power a five volt antenna feeding three volt receivers or should I get a bias tee? The internal operation of my electronics is largely a mystery to me. Thanks. -- Paul ___ 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.
Re: [time-nuts] 5V antenna on 3V receiver via dist. amp?
Paul It depends on the antenna the old ones were 5 and the new 3.3V. I believe 5V on a 3.3 antenna is bad and the other way around you loose gain. On the rcv side some rcvrs want to see a bit of current draw to say an antenna is attached. Regards Paul WB8TSL On Thu, May 2, 2013 at 3:26 PM, Paul tic-...@bodosom.net wrote: Is it reasonable to to use a GPS distribution amplifier (viz. HP 58516A) to power a five volt antenna feeding three volt receivers or should I get a bias tee? The internal operation of my electronics is largely a mystery to me. Thanks. -- Paul ___ 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.
Re: [time-nuts] Cesium wrist-watch-lite
Ah-ha, it was you that bought the 2 CSACs from eBay to put them into the sushi... On Thu, May 2, 2013 at 10:51 PM, Tom Van Baak t...@leapsecond.com wrote: ADEV_Free_Run.pdf ADEV_CSAC_Final.pdf Said, You can update your marketing literature. My measurements of your GPSDO-CSAC are more favorable (flavorful?) than what your PDF files show. See: http://leapsecond.com/pages/csac/ /tvb - Original Message - From: saidj...@aol.com To: time-nuts@febo.com Sent: Thursday, May 02, 2013 10:46 AM Subject: Re: [time-nuts] Cesium wrist-watch-lite H jwalck, the availability of the CSAC in quantities and with short lead-times is not an issue anymore. Jackson Labs Technologies can sell CSACs and can ship from stock right now. ... ___ 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.
Re: [time-nuts] Cesium wrist-watch-lite
Ah-ha, it was you that bought the 2 CSACs from eBay to put them into the sushi... No, but if those that have CSAC would get in touch with me I could make more plots. /tvb ___ 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.
Re: [time-nuts] Precise positions for GPSDOs
I fully agree with Chris, do not trust Google Earth for any serious technical use, I found errors in 100-200 m range. You only need to check where two images are stitched. Google Earth images are not produced by Google, they get them from other companies or government bodies involved in making geographical information, I can't speak about it in a whole but I actually know cases in what Google tried to get the info for free. The metric quality (or QUALITY) is not controlled by Google as far as I know. Think of Google Earth as a means of providing geographical information for the layman, for finding places, advertising and so but you don't know how accurate it is, even the date of the images can be erroneous, you can verify this yourself. I had professionally advised many customers to not rely on this info for any serious use, giving them actual examples. It is a very good and amazing product but its goal is not to make any precise measurement, and the GPS antenna position determination is in fact a surveying task. Regards, Ignacio EB4APL On 02/05/2013 17:19, Chris Albertson wrote: Google maps is NOT that good, it can be off by a lot, tens of meters. I had to have my property line surveyed some years ago to get a city building permit. So now I have two brass markers at know position. The survey crew used traditional transits from a brass benchmark. Google Earth thinks these brass markers are a few meters from here the survey crew said. (Yes I know about WGS84, we are all working in that system) I think the problem is that the lland is not flat here. If I lived in Kanas the Google system might work. But I don't think Google warps the images to account for hills and even slopes. I don't know the source of Google's error. The 1 Sigma on the self survey is about .5 meters more or less. I think the best why to measure is to let the self survey run for a full 24 hours so you get two full orbital periods of each satellite. And also to make sure you have 360 degree view of the sky.I think a view in only one direction might be biased. But yu can check Google. Find a few brass government benchmarks near your house and have Google locate them and if you got a match go with Google On Thu, May 2, 2013 at 2:29 AM, Stewart Cobb stewart.c...@gmail.com wrote: A GPSDO typically makes the assumption that the position of its antenna is fixed and well-known. That removes position uncertainty from the navigation equations, and allows all the information from the satellite measurements to be used to improve the time estimate. Errors in this position create errors in timing, with a magnitude scaled by the speed of light (one ns per foot, three ns per meter). Most GPSDOs do some sort of position averaging when they are first turned on, to come up with a good-enough estimate of antenna position. For a true time-nut, that might not be good enough. GPS surveying equipment can easily determine the position of your antenna to within a few centimeters (~20 ps). Unfortunately, such equipment is expensive and difficult to borrow. A high-end GPSDO designed today should have the ability to record phase data into RINEX files, which could be sent to a service like OPUS to find the antenna position. http://www.ngs.noaa.gov/opus/ But few do, so far. The next best idea is to locate your antenna on Google Maps. Type in the self-surveyed position to the Google search box, either as decimal degrees or as DMS, formatted like this but without the quote marks: 37.384542, -122.005526 37 23 4.35, -122 0 19.89 Click on the map and zoom in. Click on the Map box in the upper right and uncheck the 45 degree view icon. Then right-click on the spot on the picture where your antenna is actually located, and select What's here? from the pop-up menu. A green arrow marker will appear, pointing to your antenna. Left-click on the arrow, and read your latitude and longitude in both formats. Enter one of them into your GPSDO, replacing the self-survey, and enjoy increased accuracy. A true time-nut will take one more step to improve accuracy. (Sorry, but the rest of this is specific to North America. Similar details apply to other parts of the world, but I only know the recipe for the place I live.) Google Maps photos are registered (quite accurately) to the North American Datum NAD83. Unfortunately, your GPSDO operates in a different datum known variously as WGS84, ITRF, or IGS (these are all essentially the same). The difference between these two datums can be a couple of meters, easily visible on the map photos and worth 5 ns or more of time error. Fortunately, you can convert NAD83 to ITRF2008 at this website: http://www.geod.nrcan.gc.ca/apps/tmobs/tmobs_e.php For ITRF epoch, just enter today's date. For ellipsoidal height, use the value from your self-survey if you don't have a better one. You might be able to get a better one from Google Earth, or by finding a nearby benchmark from this site (US only) and
Re: [time-nuts] time-nuts newbie
Hi Warmup time on an Rb is going to be a that depends sort of thing (just like anything else). One would *hope* that you could get to 0.1 ppb of final frequency in 10 minutes from normal boat temperatures. That may or may not be what the particular unit you get at auction is doing. Next issue would be temperature. Again, who knows, but you could hope for 0.1 to 0.2 ppb over a modest temperature range. Net result would be something in the 0.2 ppb (or so) range. The ADEV on your OCXO and Rb should be good enough that it will not limit the process. Something like a PicTic should be able to give you that sort of resolution in a second. You could get a *lot* of data for a frequency locked loop in the last two minutes of the Rb's warmup. Maybe run for another minute or two to converge the lock. A good (say $30 at auction) OCXO should be able to do less than 0.1 ppb per day running continuously. The same 0.1to 0.2 ppb of tempo over a narrow range likely applies to it as well. Re-sync once a day and you probably are holding 0.2 to 0.5 ppb on average. You could get fancy and back calculate the OCXO drift as you locked it up. I would assume you can lock the OCXO this way to 0.05 ppb. That might take a few bits on a DAC. Now for the flunked this last time part: Hopefully there are 31,536,000 seconds in a 365 day long year. One ppb would be 0.031536 seconds per year. Even if you don't hit the 0.2 to 0.5 ppb average, you should quite easily hit 0.03 seconds per year. If the Rb pulls 30W for 6 minutes plus 15 W for the next 6, that's 4.5 WH per day. If the OCXO pulls 1W all the time, that's 24 WH per day. The Rb is 1/5 the total power budget. That assumes the rest of the stuff is insignificant power wise. Sounds like it would work even without an EMXO involved. I sure hope I got the math right that time…. Bob On May 2, 2013, at 5:43 PM, Chris Albertson albertson.ch...@gmail.com wrote: Turning off the Rb is a good idea. That is one of the best features of the Rb is that it will come back on from a zero power and be pretty much spot on the frequency but the phase will be random.So the question is that if you want to re-calibrate the OCXO how long to you need to compare it to the Rb. You can't look at the phase difference, that has been randomized by the power cycle. I think one could get at least 10 and maybe 100 times better than the OP's requirement and still be under the $500 limit. On Thu, May 2, 2013 at 12:59 PM, Bob Camp li...@rtty.us wrote: Hi A clock based on an eBay Rb can be set up to pull less than 10 watts. Based on 8 hours of light a day that would get you to 30 watts of solar needed to power it. That's a pretty small fraction of your 480W setup. You will get CSAC level timing and still fit your budget. For a lower power solution, wake up the Rb once a day around mid day. Only do it if the solar has surplus power. Re-sync your OCXO to the Rb. That should cut the power by a factor of about 10:1. A Google search for RBXO will turn up details on the process. Not quite CSAC performance, but far better than the OCXO alone. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Timothy Bastian Sent: Thursday, May 02, 2013 12:36 PM To: time-nuts@febo.com Subject: Re: [time-nuts] time-nuts newbie Wow I didn't know how much I was going to stir up here. As for the accuracy of the DS32khz you are correct in what the literature says. They call for an accuracy of one minute per year. The 10 seconds / year is what the gentleman who designed the clock thought would be possible. The testing he has done is giving better results than 10 seconds / year. My clock has not been running long enough to give you any meaningful results. As far as the requirements for my chronometer... there is what I would like to have and what I can afford. A clock driven by a csac (SA.45s) would be the ultimate. I am however shooting for something in the $500.00 or less price range. I have ships power available to power the clock but would like to have the ability to run on an internal battery for an extended period if needed. Say for two months. I have 4, 120 watt solar panels with 500 amp hours of 12 volt battery power. I'm shooting for a size of not more than one cubic foot. You are correct about the 100 ppb aging, which I believe will put me at +/- 3 seconds / year. A GPS time reference to set the clock would be acceptable however the whole point of having said clock is to still be able to navigate in the event of GPS failure. Thanks for all of the replies, Tim KK4FQB From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Wednesday, May 1, 2013 11:08 AM Subject: time-nuts Digest, Vol 106, Issue 1 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe
[time-nuts] Measuring Phase diference between different GPSDO
I'd like to perform some comparison between a known good GPSDO and some newcomers. I want to adjust the crystal turning point as my new GPSDO tend to wander all over the place. I see some of you are using the hp 3575A to do this. Unfortunately, they are a little out of my price range at the moment. What I do have is a an ancient hp 8407a with both 8412a and b Phase magnitude display and a 8413a phase/gain indicator. Is there any way they are usable to achieve the desired measurement? A also have a hp 5370b timer. I am not sure if it still works, but anyway, would measuring the PPS be an easier option? I also hear mention of a PICTIC, what is that? Many thanks, Mark ___ 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.
Re: [time-nuts] time-nuts newbie
Use a GPSDO. Your GPS may even have a 1pps. For what you have in mind you may not even need a OCXO. Use a TCXO.Your power will be way down.And on your boat most the time you will have horizon to horizon view. Focus is on celestial navigation. How you get the time is secondary and GPS will be the lowest cost and can be the lowest power. Bert Kehren In a message dated 5/2/2013 5:51:14 P.M. Eastern Daylight Time, albertson.ch...@gmail.com writes: Turning off the Rb is a good idea. That is one of the best features of the Rb is that it will come back on from a zero power and be pretty much spot on the frequency but the phase will be random.So the question is that if you want to re-calibrate the OCXO how long to you need to compare it to the Rb. You can't look at the phase difference, that has been randomized by the power cycle. I think one could get at least 10 and maybe 100 times better than the OP's requirement and still be under the $500 limit. On Thu, May 2, 2013 at 12:59 PM, Bob Camp li...@rtty.us wrote: Hi A clock based on an eBay Rb can be set up to pull less than 10 watts. Based on 8 hours of light a day that would get you to 30 watts of solar needed to power it. That's a pretty small fraction of your 480W setup. You will get CSAC level timing and still fit your budget. For a lower power solution, wake up the Rb once a day around mid day. Only do it if the solar has surplus power. Re-sync your OCXO to the Rb. That should cut the power by a factor of about 10:1. A Google search for RBXO will turn up details on the process. Not quite CSAC performance, but far better than the OCXO alone. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Timothy Bastian Sent: Thursday, May 02, 2013 12:36 PM To: time-nuts@febo.com Subject: Re: [time-nuts] time-nuts newbie Wow I didn't know how much I was going to stir up here. As for the accuracy of the DS32khz you are correct in what the literature says. They call for an accuracy of one minute per year. The 10 seconds / year is what the gentleman who designed the clock thought would be possible. The testing he has done is giving better results than 10 seconds / year. My clock has not been running long enough to give you any meaningful results. As far as the requirements for my chronometer... there is what I would like to have and what I can afford. A clock driven by a csac (SA.45s) would be the ultimate. I am however shooting for something in the $500.00 or less price range. I have ships power available to power the clock but would like to have the ability to run on an internal battery for an extended period if needed. Say for two months. I have 4, 120 watt solar panels with 500 amp hours of 12 volt battery power. I'm shooting for a size of not more than one cubic foot. You are correct about the 100 ppb aging, which I believe will put me at +/- 3 seconds / year. A GPS time reference to set the clock would be acceptable however the whole point of having said clock is to still be able to navigate in the event of GPS failure. Thanks for all of the replies, Tim KK4FQB From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Wednesday, May 1, 2013 11:08 AM Subject: time-nuts Digest, Vol 106, Issue 1 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: Time nut newbie (Rex) 2. Re: 10811 (John Miles) 3. Re: HP5065B !!! (Jim Palfreyman) 4. Re: Time nut newbie (Jim Palfreyman) 5. Re: Time nut newbie (Hal Murray) 6. Re: Time nut newbie (Chris Albertson) 7. Re: Time nut newbie (Attila Kinali) 8. Re: Time nut newbie (Bob Camp) -- Message: 1 Date: Tue, 30 Apr 2013 18:57:20 -0700 From: Rex r...@sonic.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Time nut newbie Message-ID: 51807680.2040...@sonic.net Content-Type: text/plain; charset=windows-1252; format=flowed It doesn't affect the general magnitude conclusions by Bruce, but as long as we are making corrections, my calculator seems to think 60 * 60 * 24 * 12 = 1036800 seconds in 12 days, not 1024800. That does come out to 115.7 days for 1 sec error. Maybe the 12-day number was a typo? -Rex On 4/30/2013 12:57 PM, Bruce
Re: [time-nuts] Measuring Phase diference between different GPSDO
Hi FIrst step is to fire up the 5370B counter and see if it works. If there's a problem re-seat all the boards and see if that fixes it. Simple way to check it is to let it count it's own reference. Once you have that working, then yes, measuring time between PPS outputs is the way to go. --- Assuming it is beyond help, then the PicTic counter board is a reasonable alternative. It will also let you measure between PPS's very accurately. Both approaches are far more accurate than you will need for checking conventional OCXO based GPSDO's Bob On May 2, 2013, at 9:33 PM, Mark C. Stephens ma...@non-stop.com.au wrote: I'd like to perform some comparison between a known good GPSDO and some newcomers. I want to adjust the crystal turning point as my new GPSDO tend to wander all over the place. I see some of you are using the hp 3575A to do this. Unfortunately, they are a little out of my price range at the moment. What I do have is a an ancient hp 8407a with both 8412a and b Phase magnitude display and a 8413a phase/gain indicator. Is there any way they are usable to achieve the desired measurement? A also have a hp 5370b timer. I am not sure if it still works, but anyway, would measuring the PPS be an easier option? I also hear mention of a PICTIC, what is that? Many thanks, Mark ___ 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.
Re: [time-nuts] Measuring Phase diference between different GPSDO
Meditating on this a bit, I assume in a strict sense, you can only consider GPSDOs phase locked if they are disciplined from the same GPS. Or is this being pedantic? ___ 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.
Re: [time-nuts] 5V antenna on 3V receiver via dist. amp?
On Thu, May 2, 2013 at 5:51 PM, time-nuts-requ...@febo.com wrote: A distribution amplifier (like the 58516A) should also be OK. If you are going to have a GPS receiver that can provide 5V to the antenna and amplifier, that would be ideal. Yes, my plan was to attach a 5V receiver to power in (port 1 on a 58516A) and 3V receivers to the DC-blocked ports. ___ 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.
Re: [time-nuts] Measuring Phase diference between different GPSDO
It is as you said Bob, I plugged the 5370b in and It flashed a zero then the display and front panel are blank. It has some other equipment in service on top of it so when I get a chance for some downtime, I'll pull it out and reseat the boards. Wish me luck! mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, 3 May 2013 11:42 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hi FIrst step is to fire up the 5370B counter and see if it works. If there's a problem re-seat all the boards and see if that fixes it. Simple way to check it is to let it count it's own reference. Once you have that working, then yes, measuring time between PPS outputs is the way to go. --- Assuming it is beyond help, then the PicTic counter board is a reasonable alternative. It will also let you measure between PPS's very accurately. Both approaches are far more accurate than you will need for checking conventional OCXO based GPSDO's Bob On May 2, 2013, at 9:33 PM, Mark C. Stephens ma...@non-stop.com.au wrote: I'd like to perform some comparison between a known good GPSDO and some newcomers. I want to adjust the crystal turning point as my new GPSDO tend to wander all over the place. I see some of you are using the hp 3575A to do this. Unfortunately, they are a little out of my price range at the moment. What I do have is a an ancient hp 8407a with both 8412a and b Phase magnitude display and a 8413a phase/gain indicator. Is there any way they are usable to achieve the desired measurement? A also have a hp 5370b timer. I am not sure if it still works, but anyway, would measuring the PPS be an easier option? I also hear mention of a PICTIC, what is that? Many thanks, Mark ___ 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.
Re: [time-nuts] Measuring Phase diference between different GPSDO
After unscrewing the great stack of (no longer used) GPIB cables, I noticed the wee switch on the back was set to external reference with no external reference plugged in! Switching this to internal, the timer burst into life. We have green to go on the 5370B, Houston! mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Friday, 3 May 2013 1:09 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO It is as you said Bob, I plugged the 5370b in and It flashed a zero then the display and front panel are blank. It has some other equipment in service on top of it so when I get a chance for some downtime, I'll pull it out and reseat the boards. Wish me luck! mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Friday, 3 May 2013 11:42 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Hi FIrst step is to fire up the 5370B counter and see if it works. If there's a problem re-seat all the boards and see if that fixes it. Simple way to check it is to let it count it's own reference. Once you have that working, then yes, measuring time between PPS outputs is the way to go. --- Assuming it is beyond help, then the PicTic counter board is a reasonable alternative. It will also let you measure between PPS's very accurately. Both approaches are far more accurate than you will need for checking conventional OCXO based GPSDO's Bob On May 2, 2013, at 9:33 PM, Mark C. Stephens ma...@non-stop.com.au wrote: I'd like to perform some comparison between a known good GPSDO and some newcomers. I want to adjust the crystal turning point as my new GPSDO tend to wander all over the place. I see some of you are using the hp 3575A to do this. Unfortunately, they are a little out of my price range at the moment. What I do have is a an ancient hp 8407a with both 8412a and b Phase magnitude display and a 8413a phase/gain indicator. Is there any way they are usable to achieve the desired measurement? A also have a hp 5370b timer. I am not sure if it still works, but anyway, would measuring the PPS be an easier option? I also hear mention of a PICTIC, what is that? Many thanks, Mark ___ 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. ___ 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.
Re: [time-nuts] Measuring Phase diference between different GPSDO
According to http://www.realhamradio.com/z3801a-turning-point.htm they use a HP 3575A phase meter to perform the measurement. Or perhaps I have misinterpreted the whole thing? I do have a temperature controlled workshop that is always 24 degrees so hopefully thermal drift won't be too much of an issue. mark -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of li...@lazygranch.com Sent: Friday, 3 May 2013 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Measuring Phase diference between different GPSDO Meditating on this a bit, I assume in a strict sense, you can only consider GPSDOs phase locked if they are disciplined from the same GPS. Or is this being pedantic? ___ 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.
