[time-nuts] Re: Why Jan 6th?
You gotta start the clock some time. 0UTC Jan 6, 1980 is when the GPS clock was started. Do a search on "0UTC Jan 6, 1980" and you will get lots of answers. regards Bill NL7F On Tue, 22 Mar 2022 17:15:10 -0700, Lux, Jim wrote: >I've been hunting around for the origin of GPS zero - Why is it 0UTC Jan >6, 1980?- - Is it a subtle joke about "Twelfth Night"? Does it have some >useful properties that "end of year" does not? >___ >time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >email to time-nuts-le...@lists.febo.com >To unsubscribe, go to and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Current-day GPS timing receivers
But there is a magazine article <https://www.qsl.net/n9zia/wireless/QST_GPS.pdf> By Brooks Shera, W5OJM. QST July, 1998. Following this article I built my unit in 1998 using his PCB and a Motorola UT+. It has been running almost continuously since then - almost 25 years. It has been thru several HP 10811 and 10844 oscillators during that time. Even though Brooks is SK his GPSDO is still running. Regards. Bill, NL7F On Fri, 18 Feb 2022 19:48:21 -0500, Bob kb8tq wrote: >On a GPSDO, there are no books. There are no magazine articles. The folks who >design GPSDOGs donGt talk about whatGs inside. ItGs not so much the >individuals, >itGs how the companies operate. IP matters and it matters a lot. Practical >stuff gets >buried as a result. You are off on a Ginvent it from scratchG expedition >(more or less). Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: HP Z3801A project update
Ed, Even with 1024 week rollover error the time should be correct. The easiest way to get correct day and date is look at it with LadyHeather. She will add appropriate number of 1024 weeks to get it right. Bill On Tue, 8 Feb 2022 20:16:32 -0800, ed breya wrote: >Regarding the Z3801A date/rollover issue, it looks like there's no easy >fix, so I can let it go. As long as it makes the 10 MHz and 1 PPS >properly, and I can check what it's doing occasionally with SatStat, I >think I'm good to go. I can figure out the date and time in other ways >too - sometimes, just knowing AM or PM is good enough. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: HP Z3801A project update
I do not know what Z3801 uses for GPS. I have several Motorola UT+ GPS modules running. Older ones with V2 firmware suffer 1024 week rollover failure. My units with V3.2 and V3.1 do 1024 week rollover correctly. If you are able to communicate with your device using Lady Heather she will correct any rollover error and display correct date. On Sat, 5 Feb 2022 16:36:15 -0500, John Ackermann N8UR wrote: >I think the problem with the Z3801 is that it expects to see specific >handshake things at startup, in Motorola binary protocol. Dropping in a >random GPS will result in a "No GPS" error. >John > >On 2/5/22 12:44 PM, Keelan Lightfoot wrote: >> Depending on whoGs GPS chipset is being used, a fix might be possible. >> IGve poked around inside the firmware of a number of Trimble receivers (so far three generations of the 4000 series, and the Placer series). Because the first week rollover occurred in 1999, any receiver made close to that date already has logic to handle a week number rollover. Finding this in the disassembled code is usually easy because they simply add 1024 to the week number, which usually appears as an add instruction with a 0x400 immediate operand. changing a 0x400 to 0x800 will extend the receiverGs lifetime another 20 years. The most difficult part of this is figuring out the processor used on the receiver, and figuring out how to get the patched firmware back into the receiver. >> >> - Keelan >> >>> On Feb 3, 2022, at 8:50 PM, Bill Beam via time-nuts >>> wrote: >>> >>> The date issue is a 1024 week rollover failure in the GPS receiver. >>> A fix is to replace the GPS receiver with one that does not have this >>> problem. >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >> email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >> >___ >time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >email to time-nuts-le...@lists.febo.com >To unsubscribe, go to and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: HP Z3801A project update
On Thu, 3 Feb 2022 18:44:54 -0800, ed breya wrote: >It seems to all be working OK, except the reported date is slightly off >- by about twenty years. It says it's 20 Jun 2002. The setup isn't >optimal - it's just a little GPS antenna propped up against the office >door glass. It only sees about three satellites, but enough to lock and >report mostly right. I assume the date thing will either fix itself >after some time, or maybe it's due to a bug. I've heard of various >rollover issues and such over the years, but don't recall any details - >since my stuff wasn't working anyway, I didn't pay much attention. >If anyone happens to know offhand, what the date issues are and any >hopefully easy fix, I'd appreciate hearing about it. The date issue is a 1024 week rollover failure in the GPS receiver. A fix is to replace the GPS receiver with one that does not have this problem. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Oncore UT+ EEPROM -
- Original Message - From: Poul-Henning Kamp To: Discussion of precise time and frequency measurement , k1...@att.net Sent: Tue, 30 Nov 2021 02:43:03 -0500 (EST) Subject: [time-nuts] Re: Oncore UT+ EEPROM - k1...@att.net writes: > I have an Oncore UT+ for a project and found that it works fine after > updating the almanac and getting a 3D fix but it never stores my location > coordinates in its EEPROM. Each time I power up it shows all zeroes in Lat, > Lon, Alt for about an hour or so until it finds satellites. With Lady > Heather I tried entering my coordinates and this leads to faster tracking. > Is this normal Oncore UT+ behavior? Any advice other than a battery backup. As far as I know, the EEPROM (Flash?) is only used for code. The almanac and other changing info is in battery-backed NOVRAM. -- And therefor your UT+ needs backup battery installed. Some do and some don't. It's an easy DIY. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: HP/Symmetricom 59551A showing wrong date
Z38XX will show date/time as given by the GPS; wrong date/correct time. Lady Heather will correct the roll over error and generate correct date. --Original Message Text--- From: va2...@ebox.net Date: Mon, 08 Nov 2021 18:07:19 -0500 Hi Bill. You are wright, time is accurate compared to other GPS clocks. I was using SatStat and Lady Heater on it, I will try Z38XX. Thank you, Claude VA2 HDD On 2021-11-08 17:49, Bill Beam wrote: > The date Mar 2002 is a 1024 week roll over error. Time should be accurate. > > If you are using Z38XX program the receiver status does not update > time in real time. > The program has a view/clock display feature that does show date/time > in real time. > > Regards, > Bill, NL7F > > > On Mon, 08 Nov 2021 17:01:05 -0500, va2...@ebox.net wrote: > >> > >>Hello to all members of the list. >>I'm testing an HP/Symmetricom 59551A that powers up OK and if I connect >>an antenna the "GPS LOCK" LED lights up after a while. >>The receiver is tracking satellites, but the status screen shows wrong >>date and time, please see attached screen capture. >>Is this a case of a GPS receiver not counting week 1024 correctly ? >>Thank you for your help, >>Claude VA2 HDD >> > > > Bill Beam > NL7F Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: HP/Symmetricom 59551A showing wrong date
The date Mar 2002 is a 1024 week roll over error. Time should be accurate. If you are using Z38XX program the receiver status does not update time in real time. The program has a view/clock display feature that does show date/time in real time. Regards, Bill, NL7F On Mon, 08 Nov 2021 17:01:05 -0500, va2...@ebox.net wrote: > >Hello to all members of the list. >I'm testing an HP/Symmetricom 59551A that powers up OK and if I connect >an antenna the "GPS LOCK" LED lights up after a while. >The receiver is tracking satellites, but the status screen shows wrong >date and time, please see attached screen capture. >Is this a case of a GPS receiver not counting week 1024 correctly ? >Thank you for your help, >Claude VA2 HDD > Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Updated TimeHat image (new gpsd!)
Hello John, I have been regularly updateing DietPI, now at V 7.7.3. Is there anything new here? Regards, Bill On Fri, 22 Oct 2021 21:11:54 -0400, John Miller via time-nuts wrote: >Hello all, >HereGs an updated system image for the TimeHat - including the latest >versions of gpsd, chrony, and DietPi. I had been meaning to get this image out sooner, but things have been pretty busy lately between work and family. >https://millerjs.org/files/TimeHat32_20211022.img.xz ><https://millerjs.org/files/TimeHat32_20211022.img.xz> >The file is a 918MB xz compressed disk image, with an md5 of >097e5b0008849dcccfc8131a4d4ba0c9 if you want to verify your download. When decompressed, the resulting image will be ~4GB and can be written out to an MicroSD card 8GB or larger. On first boot the root partition will automatically expand to fill the entire disk. >Aside from the new software versions, everything should be exactly the same. >Credentials are still timehat/timehat, it will pick up an IP address from your DHCP server automatically, it will have ssh listening on port 22, and it has a status web page on port 80. >If you donGt want to write a new image out for your TimeHat, I can provide >instructions for how to update it - the process is fairly straightforward. >DonGt hesitate to reach out if you have any issues or questions. >Regards, >John Miller >___ >time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >email to time-nuts-le...@lists.febo.com >To unsubscribe, go to and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Fri, 10 Sep 2021 21:03:05 +, Jerome Blaha wrote: >Would the use of a partial vacuum in a sealed chamber or even the septic tank >to reach a somewhat steady-state temperature be out of the question, as only radiation would dominate the temperature? >Bill's idea of a 0C water bath also sounds kind of cool and perhaps it might >be attainable with a double or triple stacked pettier cooler (reversible in voltage if your outdoor temps get below 0C) with very small tubing with coolant and two tiny DC powered pumps for redundancy with check valves to a small radiator inside the crypt water/ice bath with an RTD temperature sensor. Throw in an above-ground solar and battery backup, and the solid-state refrigeration unit could be fully self-contained and located far enough from the time crypt to not influence gravity, magnetism, quantum physics, etc. My suggestion of floating the clock in a water/ice bath raises a not so obvious mechanical issue: The clock is now no longer constrained against side-to-side motion. As the pendulum swings to and fro the clock case will move/rock fro and to. Expect large phase noise from turbulence in the bath. A 'simple' pendulum exists only in theory. A real 'simple' pendulum does not exist in any ones clock lab. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: [time nuts] Re: in-ground clock room
--Original Message Text--- From: Tom Van Baak Date: Thu, 9 Sep 2021 04:44:22 -0700 Hi Bill, I'd like undisturbed on the order of several months or years. Yes, earthquakes are possible but they are rare here and interesting so that's ok. Here's a once-in-a-decade one that I captured a few years ago: http://leapsecond.com/pend/synchronome/quake.htm The main thing is to avoid "cultural noise" -- local seismic activity caused by cars, trucks, doors opening and closing, people walking, A/C or mechanical appliances going on and off, etc. This is best done by locating the clocks away from roads, away from the house, in a solid compartment weighing many tons, underground in virgin soil or bedrock. Hi Tom, A "compartment weighing many tons" is a low pass filter good against "cultural noise" but not so good against earth quake or earth tide noise. A "compartment weighing many tons" is strongly coupled to the earth. The opposite approach is to uncouple from the earth as much as possible. Your earthquake enviornment in the Pacific northwest is similar to here in Alaska. Your precision pendulum clock is good enough to respond to monthly/daily earth tides. There is a 'catch 22' in trying to protect a pendulum clock. The pendulum depends on constant acceleration of gravity. It ain't constant. If g varies or is noisy by one part in N then that sets the point of diminishing return in your protection efforts. Bill /tvb On 9/8/2021 7:36 PM, Bill Beam wrote: Tom, How long do you expect your proposed voult to go undisturbed? I have several pendulum clocks. They are disturbed every couple of months by earth quakes. By disturbed, I mean pendulum banging against the case walls Any ground motion that can be felt will upset the clocks. Often the clocks will signal an earth quake that is not felt. Good luck. Bill Beam NL7F Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Wed, 08 Sep 2021 18:36:11 -0800, Bill Beam wrote: >On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak wrote: >>I am considering a below ground "clock room" away from the house. This >>will be for some low-drift quartz oscillators and also a couple of >>precision pendulum clocks. The goal is long-term, unattended, and very >>undisturbed operation. >>For scale, assume the room is 1 meter + 1 meter + 2 meters deep. So >>that's vastly smaller than digging a basement, but much larger than >>drilling a 8 inch round pipe. Digging down gives some natural isolation >>and temperature regulation. A couple tons of concrete gives high >>stability vertical walls for the pendulum clocks. >>If any of you have personal or professional experience with the design >>or construction of this sort of thing, especially experience with >>precast (utility) vaults or poured concrete, please let me know. >>In case this gets too off-topic for time-nuts, off-list email to me is >>fine (t...@leapsecond.com). >>Thanks, >>/tvb >Tom, >How long do you expect your proposed voult to go undisturbed? >I have several pendulum clocks. They are disturbed every couple of months >by earth quakes. By disturbed, I mean pendulum banging against the case >walls >Any ground motion that can be felt will upset the clocks. Often the clocks >will >signal an earth quake that is not felt. >Good luck. I spent a few years as a geotechnic/soils engineer and learned as others have pointed out that a thermal wave of period one year and wave length of several meters propagates downward thru the soil. Peak amplitude of a few degrees can be expected near the surface. Consider building an "oven" with the clock vault freely floating in a water-ice mixture. This will provide constant temperature (0C) and limited mechanical isolation from earth quakes. But of course this will be expensive to operate. As you know 'good' clocks require a lot of energy and generate a lot of entropy. Protecting the quartz oscillators is much easier than protecting the pendulum clocks. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak wrote: >I am considering a below ground "clock room" away from the house. This >will be for some low-drift quartz oscillators and also a couple of >precision pendulum clocks. The goal is long-term, unattended, and very >undisturbed operation. >For scale, assume the room is 1 meter + 1 meter + 2 meters deep. So >that's vastly smaller than digging a basement, but much larger than >drilling a 8 inch round pipe. Digging down gives some natural isolation >and temperature regulation. A couple tons of concrete gives high >stability vertical walls for the pendulum clocks. >If any of you have personal or professional experience with the design >or construction of this sort of thing, especially experience with >precast (utility) vaults or poured concrete, please let me know. >In case this gets too off-topic for time-nuts, off-list email to me is >fine (t...@leapsecond.com). >Thanks, >/tvb Tom, How long do you expect your proposed voult to go undisturbed? I have several pendulum clocks. They are disturbed every couple of months by earth quakes. By disturbed, I mean pendulum banging against the case walls Any ground motion that can be felt will upset the clocks. Often the clocks will signal an earth quake that is not felt. Good luck. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: Symmetricom NTS-150 Network Time Server Report
If you havn't seen it earlier look here <https://millerjs.org/timehat>. A newer version may be available. On Sat, 10 Jul 2021 14:19:56 -0500, Ben Hall wrote: >Afternoon all, >The NTS-150 arrived today from the e-place. Made a null-modem cable, fired it >up, and eventually the LED went flashing green indicating GPS lock. However...it thinks it's the year 2001...a clear indication of the GPS rollover issue. >Some googling indicates that while a firmware upgrade exists, it doesn't fix >the roll-over issue. >I quickly scanned the circuitry - its a got a Zarlink Semiconductor GPS front >end chip and separate GPS correlator, plus what seems to be a dedicated ARM microprocessor. >At the moment, it's not clear to me how much of the NTP functions are in the >ARM micro or in the other chips on-board...and if there is a TTL-serial link of known format (say NMEA) that I could cut say between the ARM micro and the rest of the NTP functionality to shotgun in a uBlox or other GPS module. >Looks like there was a thread on the eevblog webpage where someone was trying >to do that but seems that they didn't get anywhere... >So basically, I've got a nice rack-mount enclosure to enclose my next >rack-mount project...as I don't think it will ever work as an NTP server again. :) >Thanks much and 73, >ben, kd5byb >___ >time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >email to time-nuts-le...@lists.febo.com >To unsubscribe, go to and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: LH "No usable sats"
Bob, This is not an issue for an observer in AZ. GPS birds have orbit inclination 55-60deg and should be seen anywhere in the sky from AZ. AZ observer just needs to wait long enough for one to pass to the north. On Tue, 6 Jul 2021 18:55:22 -0400, Bob kb8tq wrote: >Hi >There are no GPS sats flying over the north or south poles. >Bob >> On Jul 6, 2021, at 6:13 PM, Admin wrote: >> >> Testing two different Z3801A, I wonder why I cannot receive GPS birds >> outside AZ : 290 to 315 deg. My horizon is clear and EL and AMU filters are 10 deg and 1.0, respectively. Position: 41 21 N ; 08 23 W. >> >> Your info will be very much appreciated. >> >> -- >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >> email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >___ >time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >email to time-nuts-le...@lists.febo.com >To unsubscribe, go to and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: TimeHat
I may have missed something. On my RPi 3 B+ if I plug in HDMI to a monitor after power-on there may have been a small cursor on dark screen. On Sun, 04 Jul 2021 22:33:40 -0800, Bill Beam wrote: >On my RPi 3 B+ if I plug in HDMI to a monitor I get no display. >If I power cycle With HDMI connected then it shows up on display. >So HDMI works if connected before power-on. >Regards, >Bill >I am using the preconfigured card supplied with the unit. >On Mon, 5 Jul 2021 00:23:19 -0400, Robert DiRosario wrote: >>On the Raspberry Pi TimeHat is there output to the HDMI connector, or is >>it configured to just use a serial console? >>I'm using the preconfigured SDHC card, so the software should be fine. >>If I swap out the SDHC card with a different one the systems boots fine, >>so the hardware works. >>With the card with the software there is never any output to the HDMI >>connector. >>Based on the LED on the GPS module it's locking up on the GPS signals >>just fine. After the initial lockup, it locks up again in only a few >>seconds after a power cycle. >>Robert >>___ >>time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >>email to time-nuts-le...@lists.febo.com >>To unsubscribe, go to and follow the instructions there. >Bill Beam >NL7F Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: TimeHat
On my RPi 3 B+ if I plug in HDMI to a monitor I get no display. If I power cycle With HDMI connected then it shows up on display. So HDMI works if connected before power-on. Regards, Bill I am using the preconfigured card supplied with the unit. On Mon, 5 Jul 2021 00:23:19 -0400, Robert DiRosario wrote: >On the Raspberry Pi TimeHat is there output to the HDMI connector, or is >it configured to just use a serial console? >I'm using the preconfigured SDHC card, so the software should be fine. >If I swap out the SDHC card with a different one the systems boots fine, >so the hardware works. >With the card with the software there is never any output to the HDMI >connector. >Based on the LED on the GPS module it's locking up on the GPS signals >just fine. After the initial lockup, it locks up again in only a few >seconds after a power cycle. >Robert >___ >time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >email to time-nuts-le...@lists.febo.com >To unsubscribe, go to and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: NIST 60KHz message
Jeffery My guess is: 11/07 is first Sunday in November - End of DST = NDST. On Sun, 14 Mar 2021 07:52:17 -0700, Jeffrey Pawlan wrote: >I have been using the new BPSK receiver for NIST. There are two strange >things that perhaps others can explain. >It only syncs one and only one time per day, usually around 8pm. It also >shows an interrupt count anywhere between 2 and 50 every day. I am sure >it can receive the signal more frequently than once in a day. Is that >caused by the design of the arduino software? >I also saw last night they sent a message "DST starts at 11/07 0200". >This morning it says "DST in effect" and "NDST at 11/07". Why are they >showing that date? >Regards, >Jeffrey Pawlan WA6KBL >___ >time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an >email to time-nuts-le...@lists.febo.com >To unsubscribe, go to and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
Re: [time-nuts] World's most precise.... wall clock
Hi, I had same question several years ago. You're gonna have to roll your own. Look here <https://hassam794.weebly.com/digital-clock-using-4026-ic.html> On Tue, 2 Mar 2021 17:38:24 -0500, Eamonn Nugent wrote: >Hi! >I have a perhaps silly question. I want to take an inferior medium (our >eyes) and give it something attractively precise to look at. Is there such >a thing as a digital (wall) clock with a 1PPS/10MHz/etc. input? I see that >some clocks have GPS antenna inputs, but I want to take a GPSDO and hook it >up to a digital clock. Purely for fun, as a mini project for myself while I >build my bigger clocks. >Maybe one day I'll make this work with a grandfather clock. >Thanks, >Eamonn >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ThunderBolt question
The original question was need for impedance matching between gps antenna and Tbolt. The responses were accurate and appropriate. 50 Ohm vs 75 Ohm is a nonissue. On Sat, 6 Jun 2020 07:11:49 +, John Moran, Scawby Design wrote: >Everyone ... >I must admit to being amazed at the cavalier attitude to impedance matching. I >dread to think what a state we would be in if the original telecoms networks were designed with such disregard. >OK, my background is in the old telecoms - land-line stuff where we had a >variety of impedances to work with, balanced and unbalanced, but mainly 600 ohms for the audio and line side and 50 or 75 ohms for the internal stuff. But whatever we were working with, designing to match the impedance closely was a critical parameter, and not difficult at all. Regarding connectors, you could mix and match types as long as everything you used was designed to match the same impedance and terminate the cable properly. >When you are designing amplifiers to be flat within 0.1dB over a wide >bandwidth, impedance matching matters both for steady-state amplitude settings and ringing caused by the reflections. >There is a whole discipline around transmission lines going back nearly 200 >years, for a reason. 200 years predates invention of the telegraph and the Edison recorder. I am sure that impedance matching was not an issue in that era. >OK, TimeNuts tend to be piping single frequencies around the place, but I >thought this was a place looking for precision, and playing with low-level signals, and hunting down esoteric artefacts and anomalies. Wading roughshod through transmission theory is at odds with that for me, sorry. >It's not as though designing stuff to have the right input and output >impedances is difficult. Nowadays with integrated amplifiers you can just use the brute-force method of hanging a 50 ohm resistor across a 'high-impedance' input and another 50 ohm resistor in series with a 'zero ohm' output impedance. Back in the day we designed them to inherently have the right input and output impedance and so saved throwing lots of signal away. >My humble apologies for the rant ... but I just couldn't believe what I was >reading this morning when I opened the mail. >I guess I'll get thrown out for this ... >John Regards, Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] GPS antenna splitter recommendation?
Frank, you are looking for something like ebay item 181914486443. But it's not cheap... Regards Bll NL7F On Wed, 29 Apr 2020 19:06:35 -0700, Frank O'Donnell wrote: >On 4/29/20 6:01 PM, Bob kb8tq wrote: >> HereGs a few: >Bob, thanks very much for the suggestions. >Five of the seven splitters in your list appear to offer a total of two >output ports. What I'm looking for is one that will accommodate >(specifically) three or four ports. >Of the remaining two on the list, this one: >> https://www.ebay.com/itm/Mini-Circuits-ZN4PD1-63W-S-RF-Power-Splitter-250-6000MHz-Qty-Available-GOOD/133387795141? hash=item1f0e883ac5:g:tdoAAOSwAbxel2o~ <https://www.ebay.com/itm/Mini-Circuits-ZN4PD1-63W-S-RF-Power-Splitter-250-6000MHz- Qty-Available-GOOD/133387795141?hash=item1f0e883ac5:g:tdoAAOSwAbxel2o~> >has five outputs and costs $50. Probably usable, though I was wondering >if going with additional output ports could increase possible loss? And >also, the price isn't a show-stopper but is a little high for what I was >hoping for. >The other one: >> https://www.ebay.com/itm/New-Mini-Circuits-ZB6PD-2-S-800-2000-MHz-Power-Splitter/114155096838? hash=item1a942c8b06:g:jNIAAOSwedNedT92 <https://www.ebay.com/itm/New-Mini-Circuits-ZB6PD-2-S-800-2000-MHz-Power- Splitter/114155096838?hash=item1a942c8b06:g:jNIAAOSwedNedT92> >isn't entirely clear to me. The text says it's a three-port, but I count >four visible connectors that look like output ports, and two more that >might be hiding under caps. This one goes for $19.90. >Given all of that, do either of these two seem like the optimal way to >go if I want to plug in three or four GPSDO's? >Thanks again, >Frank >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] thunerbolt, 2 problems
On Thu, 16 Jan 2020 23:32:34 -0600, Brian Lloyd wrote: >On Thu, Jan 16, 2020 at 9:20 PM Bill Beam wrote: >> Brian, >> LH can do this. Issue the command "p" to bring up the PPS control menu. >> >Thank you. LH does so much but finding the right command is a challenge. In LH Issue the command "space bar" to bring up a list of commands. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] thunerbolt, 2 problems
Brian, LH can do this. Issue the command "p" to bring up the PPS control menu. On Thu, 16 Jan 2020 20:44:43 -0600, Brian Lloyd wrote: >After quite some time I dragged out my Tbolt and fired it up. Comes up >OK. Lady Heather is happy. 10MHz is spot on (after an hour or so). >Problem is, 1pps is missing. 1pps is enabled (or appears to be). >Suggestions? >I am running Trimble Visual Timing Studio 2.03.12. It seems to know >about the Thunderbolt-E but not the original thunderbolt. Not sure it >will do the right thing. Does anyone have an older copy of the program >for configuring the T-bolt? >Thanks in advance. >-- >n++ <https://www.lloyd.aero> >Brian Lloyd >706 Flightline >Spring Branch, TX 78070 >br...@lloyd.aero <mailto://br...@lloyd.aero> >+1.210.802.8359 >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] +AFs-time-nuts+AF0- Wall Clock that takes 1PPS input
A traditional PPS (a few ms on once per second) will not work here. The square wave refered to here is at 1/2Hz, on for one second, off for one second. This is sometimes refered to as a heartbeat pulse. I use heartbeat amplitude 3-5V and capacitor of 50-100uF electrolytic. The capacitor is NOT connected in series to the clock motor but is in parallel with the motor. Yields alternating +/- pulses about 1.5V, 30-50ms. Just right to drive the clock motor. On Sat, 4 Jan 2020 18:05:00 -0500, MLewis wrote: >Neat trick! >The AA driven quarts clocks obviously use very little current, but I >don't know how much. >When using a PPS to drive such a clock directly: >- is the current draw enough that one should isolate the PPS signal to >the clock so the clock/coil draw doesn't affect the PPS signal being >read properly from other devices? >Thanks, >Michael >On 04/01/2020 5:46 PM, Bill Beam wrote: >> The purpose of the series capacitor is to take the derivative of the square >> wave. >> The first derivative of a positive square wave is a short positive pulse at >> the >> leading edge followed by a short negative pulse at the trailing edge. >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] +AFs-time-nuts+AF0- Wall Clock that takes 1PPS input
The purpose of the series capacitor is to take the derivative of the square wave. The first derivative of a positive square wave is a short positive pulse at the leading edge followed by a short negative pulse at the trailing edge. On Sat, 4 Jan 2020 17:27:15 -0500, Philip Gladstone wrote: >You don't need a full square wave -- just a 100ms pulse every second with >opposite polarity. >Philip >On Sat, Jan 4, 2020 at 5:16 PM Neville Michie wrote: >> It is far simpler to remove the clock battery, connect to the coil >> terminals, >> use a series capacitor and drive with a 0.5 hertz square wave. Just find >> an >> appropriate capacitor for the clock and the square wave voltage. >> >> cheers, neville michie >> >> >> > On 5 Jan 2020, at 05:00, Gregory Muir wrote: >> > >> > Why not design a circuit similar to the GPSDO approach utilizing the 1 >> pps to synchronize a 32.768 kHz oscillator which could be applied to the >> clock's divider input after it's internal oscillator has been disabled? >> You could probably apply the signal directly to where the crystal used to >> reside. This would allow universal application to any cheap clock with an >> accessible crystal.. >> > >> > Greg >> > >> > ___ >> > time-nuts mailing list -- time-nuts@lists.febo.com >> > To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> > and follow the instructions there. >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Antique pendulum clocks
On Tue, 19 Nov 2019 20:10:14 -0500, Philip Gladstone wrote: >I've started to monitor the individual ticks on a grandfather clock from >the 1790s. Essentially I timestamp whenever the pendulum breaks/restores a >light beam. >The data that I get is surprising in that the pendulum swing varies >according to the position of the hands on the clock. It appears that the >amplitude of the swing depends on the driving force imparted by the >escapement. Since the second hand is not counterweighted, there is slightly >more energy available to drive the escapement during the first half of each >minute and slightly less in the second half. There is much bigger effect at >the end of each hour when the mechanism has to move a lever to trigger the >strike mechanism. This 'end of hour' effect changes the pendulum swing >enough so that the period is noticeably affected (maybe by 300ppm) >Anyway, my google-fu did not reveal anybody else interested in this >stuff... Anybody here interested? Most people interested in this problem have been dead for about 200 years. Also note that as the clock gets old and dirty it will begin to stop at 8:45. Now if you want to see another old interesting clock problem look up the 'Thursday afternoon effect'. >Philip >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] DC distribution
On Sat, 5 Oct 2019 18:03:33 -0400, MLewis wrote: Snip >An engineer told me what was up, and I cut open some connections that >seemed solid to check. In each case there was a gob of solder at the >end, but only some trace solder within the first part of the strands, >with minimal contact between the wire and the crimp. I've cut one open a >number of times over the years since, to show such to people. The engineer failed to explain why this is an electrical problem. (Note: >NASA will not accept crimped connections of tinned stranded or tinned >solid wire. I've no idea why, but I figure it's a given that they know a >lot more about terminations and connections than I ever will.) I know why They don't like diodes/rectifiers in connections. Crimped connections can produce point contact junctions thru the tinning layer resulting in rectification. Snip >I've heard a lot of speculation over the years as to why this difference >in clarity, but nothing that seems completely credible. The closest to >credible speculation I've heard is: >- a poor connection results in multiple signal paths resulting in a >sightly overlapped signal so the signal is no longer clear, or To create a multipath error of 1 electrical degree at 20KHz (inaudible) requires a path error of about 30m. Not going to happen in a cm connector. >- a poor connection has multiple connections and combined with eddy No eddy currents >currents in the connector you can get tiny RC paths instead of a single >long connection, so you've got multiple re-injections of a delayed >signal that smooths tiny changes in voltage, which is your signal. For R<~1ohm, C<~1pF the time constant is <~10e-12sec. Not in the audio domain. >Causation is clear. Not clear! >The explanation? No idea. The explination: A poor connection rectifies. For 1% difference between forward and reverse conduction expect to hear about 1% THD. To make matters worse the rectification will likely be nonlinear with current thru the connection further increasing THD. Snip Regards Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Thunderbolt frequency error when locked
I have three units running. Lady Heather reports osc error as <+/-10-100 ppt, about 10 milliHz. This is real time reporting every sec. On Wed, 2 Oct 2019 18:32:19 +, David Van Horn via time-nuts wrote: >I'm writing up a presentation for some sales guys, and I need the typical >frequency error of the thunderbolt in marketing friendly terms like "plus or minus X millihertz" >What would that number be? Short term only. >-- >David VanHorn >Lead Hardware Engineer >Backcountry Access, Inc. >2820 Wilderness Pl, Unit H >Boulder, CO 80301 USA >phone: 303-417-1345 x110 >email: >david.vanh...@backcountryaccess.com<mailto:david.vanh...@backcountryaccess.com> >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Even Seconds Pulse option (1PP2S), HP 58503B
40 to 100 microF electrolytic will work. On Mon, 30 Sep 2019 12:21:06 +1000, Neville Michie wrote: >If you have a square wave at .5PPS and you connect a large series capacitor to >the coil of a quartz clock >(less battery) you get alternating seconds pulses drive to an analogue dial. >50 ohms will easily drive the about 1k coil. >Cheap quartz clocks make good slaves. >cheers, >Neville Michie >> On 29 Sep 2019, at 22:56, Gregory Beat via time-nuts >> wrote: >> >> A new resident arrived at the GTime CaveG this weekend, the >> HP/Symmetricom 58503B. Just the plain front panel (4 LEDs) model, without Option 1 (VFD clock display). >> Acquired in USA, cheaper than current Asian exporter. >> https://accusrc.com/uploads/datasheets/4975_58503b.pdf >> >> Supposedly stored in a closet since 2010 (verified by its diagnostic logs), >> the unit only had 2,000 hours of operation. >> Today, it happily has a GPS Lock and is currently Gre-learningG where >> the 1 PPS and 10 MHz outputs wandered (taming Lazarus). >> G >> One surprise, it has Option 2 (1PP2S) installed on its Rear Panel. >> >> Option 002 : 1 PP2S (One-Pulse-Per-Two-Seconds) connector for outputting a >> pulse every other second, synchronized to the even seconds in GPS time. >> Pulses occur on even-numbered seconds (i.e., 2 seconds, 4 seconds, etc.). >> === >> QUESTION: >> What Specific Applications would use this 1PP2S output regularly?? >> >> greg >> >> Sent from iPhone 6s >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >_______ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Am I doing something wrong?
he issue of whether it is a Nortel/Trimble Thunderbolt or just a >> Thunderbolt wouldn't cause the current problem that I am having now in >> a unit that previously worked perfectly for me. >> >> Just so you know that my heather.cfg file is "OK" and not responsible >> for any problems, here it is: >> >> /9 >> /rx >> /br=9600:8:n:1 >> /ro=1* >> /tz=-5EST/EDT >> /b=1 >> /tb=W3SZ >> /gm >> /gw=0 >> /gqw >> /gcs- >> /gcg >> >> To further document that this issue is not a "setup" problem, I did >> another factory reset of the unit and then did not use Lady Heather >> but only monitored function with TBoltMon.exe and I did not do any >> setup with that utility until the self survey was done and more than >> two hours had passed, and then I only set and saved the position. >> Function and- results were unchanged, and the unit was still stuck in >> Power-Up mode and DAC voltage was still stuck at zero, but everything >> else was normal according to the TBoltMon readouts. >> >> Thanks again and 73, >> >> Roger >> W3SZ >> >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Am I doing something wrong?
Roger, Bob's idea is a good one. Your last Oct screen shot shows DAC=+0.475V. Try setting DAC=+0.5V. Don't even need a counter since L H shows osc error. Hope that DAC does not hit a rail. If this does achieve a steering lock then be sure to set the DAC initial value using & >> I. This will cause a good restart after power cycle or reset. Then do an Autotune. Bill On Wed, 25 Sep 2019 13:34:14 -0600, Bob kb8tq wrote: >Hi >Best guess is that the OCXO is too far off frequency for the GPSDO to even try >to lock. >Quick check would be to run the DAC manually while watching the output with a >counter. >It should tune +/- 10 Hz or so either side of 10 MHz. >As far as anybody knows, there are no official TBolt schematics. People have >traced out >bits and pieces of the circuit. The biggest issue is that a lot of it is >burried in FPGAGs or >in firmware. >Bob >> On Sep 25, 2019, at 10:20 AM, Roger Rehr W3SZ wrote: >> >> Thanks to Bill and Mike for the very helpful info! >> Unfortunately, doing warm reset, cold reset, factory reset, multiple self >> surveys did not solve the problem. >> Forcing Disciplining to Enabled did not help. >> Tuning the oscillator did not help. >> >> I can manually control the DAC voltage using appropriate commands and the 10 >> MHz output changes appropriately following each manual command. >> But the DAC voltage doesn't respond to GPS input. >> >> I note from my old records that when the unit is working properly and the >> DAC IS being controlled by the GPS, Lady Heather still says "Doing fixes", because fixes are in fact being done. But when Lady Heather is working properly, she says that the Discipline mode is "Normal" instead of "Power-Up" as she does now. >> >> I used TBoltMon.exe to see if I could get any more info on the problem. In >> TBoltMon.exe's GUI under "Disciplining Status" Mode is listed as "(1) Power-up" and Activity is listed as "(1) Osc Warm-up". >> >> So I wondered if the problem is that the Thunderbolt thinks that the >> oscillator has not warmed up and therefore won't come out of Power-Up mode. But the manual says that the Tunderbolt won't start acquiring satellites and do the self survey until it has warmed up. And the situation is that it has acquired satellites and it has done the self survey, both of which would suggest that it thinks that the oscillator HAS warmed up. The the TBoltMon reading on the oscillator status seems to be inconsistent with how the Thunderbolt is performing; it is acting like the oscillator IS warmed up, at least in some respects. >> >> Are there any schematics or diagrams or service manuals available for the >> Thunderbolt? I couldn't find any with Google. >> >> Thanks again to Bill and Mike and all for your help! >> >> 73, >> >> Roger >> W3SZ >> >> >> On 9/24/2019 1:32 PM, Roger Rehr W3SZ wrote: >>> HI All, >>> >>> I am wondering if I have set up my Trimble Thunderbolt wrong. >>> >>> I have corrected for roll-over and everything looks good in Lady Heather >>> but the Thunderbolt stays in Power-up mode according to Lady Heather, and is always "doing fixes" even though I have entered the lat and lon for a fixed location. >>> >>> According to Lady Heather Disciplining is OK, and of course the log >>> reflects this as well >>> >>> #! new minor alarm state 0800: Tracking sats Discipline OK : at tow >>> 235167 >>> >>> You can see the situation from this screen grab of Lady Heather: >>> http://w3sz.com/TrimbleLadyHeather.PNG >>> >>> Have I done something wrong in configuration, or is this consistent >>> Power-up mode and "doing fixes" notation the expected behavior? >>> >>> I am using the Thunderbolt as at 10 MHz source for my microwave station. >>> >>> Thanks in advance and 73, >>> >>> Roger Rehr >>> W3SZ >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Am I doing something wrong?
How long has unit been powered on? GPS looks ok but osc is not locked, osc error is high at 500K ppt, should be below 50ppt. DAC shows no activity. Give it time (maybe an hour) to see if it goes from 'Power-up' to 'Normal" On Tue, 24 Sep 2019 13:32:18 -0400, Roger Rehr W3SZ wrote: >HI All, >I am wondering if I have set up my Trimble Thunderbolt wrong. >I have corrected for roll-over and everything looks good in Lady Heather >but the Thunderbolt stays in Power-up mode according to Lady Heather, >and is always "doing fixes" even though I have entered the lat and lon >for a fixed location. >According to Lady Heather Disciplining is OK, and of course the log >reflects this as well >#! new minor alarm state 0800:- Tracking sats- - Discipline OK- - : at tow >235167 >You can see the situation from this screen grab of Lady Heather: >http://w3sz.com/TrimbleLadyHeather.PNG >Have I done something wrong in configuration, or is this consistent >Power-up mode and "doing fixes" notation the expected behavior? >I am using the Thunderbolt as at 10 MHz source for my microwave station. >Thanks in advance and 73, >Roger Rehr >W3SZ >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP 10811 stabilizing time
I have several 10811. Pin 6 on the edge connector is EFC input, Pins 2, 4 and 5 are GND. The HP Service Manual is out there on the web. It's worth a search. One of my units spent several years on the shelf. I put it back in service using a Motorola UT+ GPS receiver and Brooks Shera regulator to discipline the oscillator. After half a year continuous on, the ageing drift is not yet quite zero. EFC voltage is still drifting at ~<10-20 mV/month. Regards, Bill, NL7F On Mon, 22 Jul 2019 01:53:14 + (UTC), Perry Sandeen via time-nuts wrote: >Yo Bubba Dudes!, >I bought a HP 10811 from ebay for $36 and shipping. >I installed it in my HP 5335a counter.- After running continuously for about >90 days it was down to about 4 to 6- parts in -10.- I couldn't adjust it for better accuracy as HP in their infinite and inscrutable wisdom provided a edge connector for the 10811 but didn't make provision for EFC one had only the course adjustment.- Sheesh! >Now maybe I was very lucky in my ebay purchase.- On ebay prices seem to go >from $125 to around $60.- One of the lower priced sellers advertise that their 10811's are *tested* but no details. >Regards, >Perrier >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] The forbidden question
You will have an answer if you can answer the question: "Why is an optical microscope needed when unaided vision is good enough?" My PhD is in high energy particle physics ca 1966. This is not intended to be 'Dismissive and/or snarky'. Your statement "Dismissive and/or snarky replies will be deleted unread." has a logic issue Regards (73) On Tue, 4 Jun 2019 12:43:04 -0400, William H. Fite wrote: >Warning: Potentially heretical material below >Let me begin by saying I am neither an engineer nor a time expert. My PhD >is in statistics and my spouse's PhD is in theoretical computer science, >working on quantum computer algorithms. Neither of us claims any special >expertise when it comes to time and frequency measurement. I am a radio >amateur and I came to this group following a recommendation from John >Ackermann, who very kindly answered some questions for me regarding the >amateur radio frequency measurement test. I thoroughly enjoy the dialogue >here and I think that I have learned a bit about the subject though, by any >standard of this group, I am the rankest newbie. >My question is a serious one. I am not trolling, nor am I trying to begin >an argument, nor am I implying criticism of anyone or any endeavor, here or >elsewhere. >What useful purpose, if any, is served by the continuing evolution of >clocks like NIST-F2 that now achieve accuracy along the lines of one second >per many billions of years? Are there tangible benefits to be had? I >consulted an astronomer friend who advised that the current generation of >clocks would allow a suitable space vehicle to plant a probe squarely in >the middle of Alpha Centauri, if rocket technology existed to do so. We >have many friends in the academic computer science community who say that >neither conventional nor quantum computers that exist at present or in the >projectable future require anything like this kind of accuracy. >By no means am I questioning the value of new knowledge qua knowledge. For >theoreticians like the one to whom I am wedded, no justification is needed >beyond the words of mountaineer George Mallory: "Because it's there." I'm >sure that engineers and scientists in the field of time and frequency >measurement feel the same. From that perspective, there need be no >rationalization beyond the desire to do it just a little better than it has >been done. >Please don't lecture me about the value of science for its own sake. My >career has largely been built on that principle. I'd like to be informed as >to present or anticipated applications that require such accuracy. Are we >developing these incredible devices just to push boundaries? Or do they >have some practical purpose? >I'll appreciate thoughtful answers. Dismissive and/or snarky replies will >be deleted unread. >Thanks for your help. >-- >Homo sum humani a me nihil alienum puto. >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] PPS clock module
I went thru this several years ago and ended up home brew with the following circuit: <https://hassam794.weebly.com/digital-clock-using-4026-ic.html> For adjustment of time indication I added switches to run hours and minutes at 1 pps rate and a switch to stop seconds. Some always on leds for colons to make it look like a clock. There are many other circuits out there but no complete commercial units. On Sun, 27 Jan 2019 15:48:40 -0500, John Ackermann N8UR wrote: >I'm putting together a portable Rb standard and thought it would be nice >to include a clock on the panel. I probably haven't hit the magic >search words, but I haven't found what I'm looking: a module (no >enclosure) that is driven by an external PPS and shows at least HH:MM:SS >in 24 hour format on a small LED or LCD display. >I can whip something together with an Arduino, but rather than reinvent >the wheel I thought I'd ask if anyone knows of something that's ready to go. >Thanks, >John >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Calculating time of lunar eclipse
According to my copy of Guide9 (Pluto project) full moon occurred at 21 Jan 05:16:04 UTC. On Mon, 21 Jan 2019 07:07:31 +, Mark Sims wrote: >While on the subject of the accuracy/reliability of various algorithms and web >pages showing various astronomical data, we had a full moon / total lunar eclipse in the northern hemisphere. And not just any full moon, but a Super Blood Werewolf Zombie Apocalypse full moon (or some such drivel spouted by all the TV stations). >Anyway, I wanted to know when the eclipse was at it's maximum. Most web sites >gave a time here as 23:12, some differed by several minutes. None gave the time to the second. That just won't do for a moon worshiping time-nut, will it? So, I tricked up a version of Lady Heather to do a screen dump when the difference of the sun and moon azimuth and elevation were at a (180 degree) minimum. Looks like it happened at 23:12:04 >Heather's sun position code (based on Grena's algorithm 5) is VERY accurate >(and quite simple). The moon position code is pretty good... a better version would require several thousand lines of code evaluating a zillion polynomials with hundreds of terms. >Anyway,, attached is a copy of the screen dump. Note the difference in the >sun/moon az/el values and also the calculated moon phase. >Does anybody know of a reliable source of the true time of the lunar eclipse >down to the second (or better)? Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
