[time-nuts] Re: GPS failed
With the new 5G hardware, we are seeing all manner of new interference, some of it quite broad-band. A good antenna with sharp SAW filter may help, but not if the emmisions are in-band. Besides broad-band, there also can be 2nd harmonic emissions that cause interference. We had this problem with an Iridium ground station (just above the GPS L1 frequency) for scientific balloon data that had a new cell installation placed nearby. We had (and thankfully were able to) have the cell base station shut down while we were flying. 73, David N1HAC On 7/11/22 9:27 AM, paul swed via time-nuts wrote: Skipp I am aware at least in the US that there is the possibility of 5G interference along with newer possible bands that 5G can use. I have read several articles in a publication called GNSS. Thats why I am using wwvb at 60 KHz. Humor intended. Regards Paul WB8TSL On Mon, Jul 11, 2022 at 8:49 AM skipp Isaham via time-nuts < time-nuts@lists.febo.com> wrote: Hello to the Group, I'd like to get some opinions and war stories regarding GPS reliability at high RF level and elevation locations. Background: Three different hill-top GPS receivers, all different types, using different antennas mounted on an outside fixiture, plain view of the open sky, all stopped working. Test antennas were brought in and placed on a fixture well away from the original antennas, the recevers went back in to capture and lock. From what I understand, the original antennas are what I would call straight preamp with no pre-selection / filtering. The ordered and now inbound replacements are said to contain a SAW filter system. It is the intent of the client to just place these "improved antennas" in to service and get on with life. I would suspect a GPS antenna (and receiver) could be subject to RF overload or blocking, however, we're assuming nothing major has changed at the site, nor any nearby location. One might think there are more GPS receivers being pushed out of reliable operation by the world around them, I'm just not hearing those stories from a lot of people using them (GPS receivers). Any new install GPS receiver antenna ordered will/should contain some pre-selection to potentially avoid a problem, even some years down the road? Seems like that's where things are going... no more off the shelf, wide band, (hot) preamplified GPS antennas in busy locations? Thank you in advance for any related comments and/or opions ... cheers, skipp skipp025 at jah who dot calm ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com
[time-nuts] Re: DIY Low offset Phase Noise Analyzer
Are you sure the PN floor of the measurement instrument isn't the limiting factor? David -Original Message- From: Erik Kaashoek via time-nuts Sent: 04 July 2022 10:14 To: time nuts ; Erik Kaashoek Cc: Erik Kaashoek Subject: [time-nuts] DIY Low offset Phase Noise Analyzer : At 10kHz offset the Phase Noise of the DOCXO should be -150dBm but unfortunately either the noise of the ultra low noise opamps or the Phase Noise of the AR60 is almost 20dB higher. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com
[time-nuts] Re: Should a double oven XO be thermally isolated or just draft protected?
On Fri, 1 Jul 2022 at 22:49, Hal Murray wrote: > > I think the 5370B has a fan so a shroud to keep the air currents away from > the > OCXO seems like a good idea. > > Is there a fan in the 5352B? > > Yes there is. But the 5352B runs a lot quieter and cooler than a 5370B, which would suggest that not as much air is being blown around inside the frequency counter. There’s not even a heatsink on the back of the frequency counter I see your other comment about drafts. It got me thinking that my HP GPS frequency standard is probably located in about the worst possible place for drafts - right below the air conditioning unit. I will look at moving that. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkir...@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com
[time-nuts] Re: What's the best HP OCXO for frequency counter reference?
On Tue, 28 Jun 2022 at 20:04, Bob kb8tq via time-nuts < time-nuts@lists.febo.com> wrote: > Hi > > The “typical” 10811 struggles when shut down for a while. Once the oven > is turned off, the boards are just sitting there in whatever environment > your > lab provides. Do they soak up humidity or is it something else? We could > (and have) debated that quite a bit. > Part of my problem is that if I ever wanted to sell this, I'd like to sell it with an oven that was designed to meet the specifications given in the frequency counter manual for option 010, which are better than the 10811A. Another quite practical issue is setting the blinking frequency, as the pot on the oscillator seems too touchy. I set a signal generator to 20 GHz, which was fed from a GPS frequency reference. The output of the signal generator was then fed into the counter. Getting the counter to read within 100 Hz is extremely difficult, as the tuning control is too coarse. As I write the frequency counter is reading 83 Hz higher than 20 GHz. To be honest, that's "good enough" for what I am *practically* going to need. But I would like to do better if possible. Dave ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com
[time-nuts] What's the best HP OCXO for frequency counter reference?
I have a 5352B 40 GHz frequency counter which was fitted with a TCXO. I removed that and fitted an HP 10811-60111 S/N 2332A17049 which I removed from a 5370B time interval counter - I have a few of those, and the microwave frequency counter needed the oven more than the time-interval counter. Looking at the specification of the 5352B, there were 3 oscillator options * Standard TCXO * Option 001 Oven time based. Long-term aging < 5 x 10^-10 / day after 24 hour warmup. < 1 x 10^-7 / year for continuous operation. * Option 010 High stability time base. Long term aging < 1 x 10^-10 / day. < 3.6 x 10^-8 / year for continuous operation. To be honest, when the instrument is here, I will use a GPS reference. But I might want to take it to the amateur radio club sometimes. I would like to get the best oscillator I can. Are any models going to be better than others, or by this time, is it just pot luck? I think it's the latter, but maybe some are double-ovens and some single. With the exception of power cuts of up to a few hours, the HP 10811-60111 I fitted has been continuously powered on for a few years. But due to soaring power costs, I am going to switch my ovens off. Dr David Kirkby Ph.D Email: drkir...@kirkbymicrowave.co.uk Web: https://www.kirkbymicrowave.co.uk/ Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com
[time-nuts] Re: Is SC the most stable cut for lowest phase noise?
On Fri, 10 Jun 2022 at 17:39, Lux, Jim via time-nuts < time-nuts@lists.febo.com> wrote: > > On the subject of rapid warm up. I suppose if you had a need, one could > dump as much power as you need into the heater. Turn on oscillator, > lights in room dim for a few moments. > Is that not likely to damage a crystal? Different parts of the crystal and likely to be at significantly different temperatures at the same time, putting a lot of stress on the crystal due to a thermal gradient. It's probably a bit academic, as nobody is going to make an oven that heats up in fractions of a second, but if one did, I suspect it might not do the crystal a lot of good. This is only an educated guess - I don't have anything to back it up. At the other extreme, would there be any advantage in actually heating the crystal very slowly, over the course of an hour/day/week, so the temperature gradient across the crystal is very small? Of course, if an oven took ages to reach the correct temperature, it would be inconvenient for most applications, but for some applications, the advantages might outweigh the disadvantages. Of course, if one does this, I suspect one would have to cool the crystal slowly too to prevent a significant thermal gradient across the crystal. I know it's a bit different, but I have a 600 mm f4 Nikon camera lens. I was told that Nikon cools the front element over a period of 6 months to reduce stresses in the glass. Dave ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com
[time-nuts] Re: Suggestions solicited for Pi/GPSDO ntp server
On 26/05/2022 17:44, Lee Reynolds via time-nuts wrote: Hi, Lords of Time! (Been a lurker for many years, just know too little to add but am always fascinated by your discussions. It almost reads like theological discursions at some points, it gets into such fine and abstruse points!) I think it's about time to retire my old former cell site GPSDO. Technology has improved and I'm thinking of setting up a Raspberry Pi based ntp server for the local devices. (I also have some spare Pi's, so...) Does anyone have any suggestions for a good solid Pi/GPSDO setup and code for such a purpose? Something like Leo's device but, of course, much cheaper? Any suggestions would be greatly appreciated. TIA, Lee Lee, What accuracy are you wanting for your "local devices"? A Windows box NTP server could give you hundreds of microseconds, a Raspberry Pi tens of microseconds. With the RPi you could have several local GPS/PPS/NTP servers perhaps located in different parts of the building. Hal has given some good advice. I particularly sympathise with the "out of date" part, where Linux OS changes almost on the basis of (it sometime seems) "if it works, break it!". I've built a few of the Raspberry Pi NTP servers, and in practice the Ethernet being over USB isn't an issue, but if you can get a Pi 4 that would reduce that problem. But the Pi4 isn't so easily obtainable right now, and it generates rather more heat, so the stability of the CPU clock isn't as good as on earlier RPi models. Ambient temperature can be a problem, so try to keep the RPi out of direct sunshine, preferably in a cupboard away from any heating. All to keep the CPU clock stable! No need for a display, it can all be built from the command line over SSH. Ask if you have further questions. David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com
[time-nuts] National Physical Laboratory (NPL) open day in the UK
https://www.npl.co.uk/open-day Tickets are available for different entry times. My experience is the day is never long enough, so one really wants to be there as early as possible. There's tons of stuff on time-keeping there, and also some on voltage measurements. I cc'ed to both time-nuts and volt-nuts, although I suspect there's a fair number of people who are members of both groups. My past experience is that NPL does a very good job of these open-days. They manage to get plenty of things of interest to young children, yet there's plenty of stuff to get PhDs scratching their heads. To you guys in the USA or elsewhere, where places like NIST do not have open-days, perhaps you can use the fact NPL does, to get your own national metrology labs to have open-days. Dr David Kirkby Ph.D Email: drkir...@kirkbymicrowave.co.uk Web: https://www.kirkbymicrowave.co.uk/ Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT. ___ 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: GPScon peogram
On 06/04/2022 00:33, Lon Cottingham wrote: How does one acquire GPScon? The only source I find in from Jackson's Labs ant it only works with Jackson Lab's products. 73 de Lon, K5JV I suppose it isn't this program: http://www.realhamradio.com/gpscon-info.htm What about ublox U-Center or Lady Heather? David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: Low Phase Noise70 10 MHz bench signal source sought
If they are all in the same enclosure and powered from the same supply how are you going to prevent injection locking? Or do you want them to injection lock? D. -Original Message- From: g...@hoffmann-hochfrequenz.de Sent: 02 April 2022 08:22 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Re: Low Phase Noise70 10 MHz bench signal source sought I still have this idea to lock a flock of MTI-260 (which I have) to a common Lucent-GPS, slowly to keep them as independent as possible, but in-phase. ___ 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: GPSDO - GPS1300-10-1000 by RFX Ltd. UK
On 02/03/2022 17:34, va2...@ebox.net wrote: Hello to all members. I want to add to my lab a Pi based display that would show a GNSS SV map like the one attached to this message. Any suggestions ? Thank you ! Claude VA2 HDD Claude, I would look into gpsd. I guess someone will have made a graphical add-on, if not a text simulation of a graphical display. Mine was u-blox u-center with a serial line actually from an RPi HAT, operated stand-alone. 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: GPSDO - GPS1300-10-1000 by RFX Ltd. UK
On 01/03/2022 22:43, Bob kb8tq wrote: Assuming you are south of Hadrian’s Wall, you will have GPS sats overhead at least occasionally. The bulk of what you will be able to “see” will be to the south. If you really have a good antenna location and are a bit north, you may be able to “see” sats on the other side of the north pole. More or less, there is a big coverage blank area over the poles with GPS. Even north of Hadrian's wall we get GNSS satellites overhead. Here's with an indoor antenna dual-band setup. None reach 40 dB. David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv___ 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: GPSDO - GPS1300-10-1000 by RFX Ltd. UK
<http://www.leobodnar.com/shop/index.php?main_page=index=107=15a 92055b16c36edbdc83f4ac8fb8abc> D. -Original Message- From: David C. Partridge Sent: 28 February 2022 13:56 To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK Maybe take a look at: http://www.leobodnar.com/shop/index.php?main_page=index=107=15a9 2055b16c36edbdc83f4ac8fb8abc -Original Message- From: John Moran, Scawby Design Sent: 28 February 2022 13:26 To: time-nuts@lists.febo.com Subject: [time-nuts] GPSDO - GPS1300-10-1000 by RFX Ltd. UK With all this interesting talk about - a) How hard it was to build a GPSDO from scratch and b) How, to measure a signal accurately, you need a reference circa 10x better I started to get worried since I want to do both. To help with the latter I have acquired an HP5370A that just needs picking up from Scotland, where I was hoping to maybe pick up some surplus oscillators as well. But the 10x specs in the discussions got me worried enough to look around for a known good GPSDO rather than buying a bag-full from China and trying to sort out a good one. I found this - https://www.rfx.co.uk/pdfs/GPS_OCXO_1300_10_module.pdf and have been quoted £500 as a special deal (they normally have a £1,000 minimum one-off charge). Can anyone please pass some sort of judgement on whether its specs are good enough to stand in as my master reference until I can find a Rubidium device on this side of the pond. John ___ 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. ___ 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: GPSDO - GPS1300-10-1000 by RFX Ltd. UK
Maybe take a look at: http://www.leobodnar.com/shop/index.php?main_page=index=107=15a9 2055b16c36edbdc83f4ac8fb8abc -Original Message- From: John Moran, Scawby Design Sent: 28 February 2022 13:26 To: time-nuts@lists.febo.com Subject: [time-nuts] GPSDO - GPS1300-10-1000 by RFX Ltd. UK With all this interesting talk about - a) How hard it was to build a GPSDO from scratch and b) How, to measure a signal accurately, you need a reference circa 10x better I started to get worried since I want to do both. To help with the latter I have acquired an HP5370A that just needs picking up from Scotland, where I was hoping to maybe pick up some surplus oscillators as well. But the 10x specs in the discussions got me worried enough to look around for a known good GPSDO rather than buying a bag-full from China and trying to sort out a good one. I found this - https://www.rfx.co.uk/pdfs/GPS_OCXO_1300_10_module.pdf and have been quoted £500 as a special deal (they normally have a £1,000 minimum one-off charge). Can anyone please pass some sort of judgement on whether its specs are good enough to stand in as my master reference until I can find a Rubidium device on this side of the pond. John ___ 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.
[time-nuts] Re: 4096 PLL - how to switch off on-chip VCO
The part number has been garbled a bit, but the members of the family are 74HC/HCT4046, 74HC/HCT7046 and 74HCT9046, the last one having a significantly better phase detector. The on-board oscillator should not be a issue, but on the '4046 and '7046, pin 5 held low disables the oscillator. On the '9046, pin 5 shuts the whole chip down, but there is a way to force the oscillator to a zero frequency. 73, David N1HAC On 2/22/22 8:09 AM, Bob kb8tq wrote: Hi Best guess: Your 10 MHz (for whatever reason) is being turned into a fast edge square wave. That’s dumping current spikes into the supply and ground on your board. You have a really wide spectrum as a result ( usually well up into the GHz region). That “stuff” is going here / going there. Some of it is getting into your amplifier / filter chain by one route or the other. It looks like modulation because of the filtering in your multiplier chain. Since the PLL chip does the same thing ( when it generates 10 MHz into the phase detector, there are two possible sources of the fast edges and current spikes. Yes this makes tracking things down a bit more fun. Either way, the answer is board layout / bypassing / decoupling related. If you want to go with a different “low frequency” phase detector chip, the ADF4002 has been a go to part for quite a while. Bob On Feb 21, 2022, at 9:27 PM, g...@hoffmann-hochfrequenz.de wrote: Hi! I'm building a clock source for my LMX2594 15 GHz PLL. I want to max out the LMX2594 phase comparator frequency; that means 300 MHz for fractional operation. The VCXO is a 100 MHz ECOC-2250 crystal oven by ECS because I have it, and it's tripled. Dumping its output into a pair of 1G125 line drivers gets me this spectrum: (100 MHzpng) The 300 MHz is quite prominent with not much of a loss. I dumped it into a 300 MHz filter, 3 poles, C-coupled, then a sot-89 MMIC and another 3 poles. That cleaned up the harmonics quite good. Sorry, there were no 300 MHz SAW-filters available. All obsoleted. The filter is 6 Murata 0603 SMD inductors and fixed Cs. Still a bit to the low side; that can be fixed. BUT - there is a problem. The 100 MHz can be locked to an external 10 MHz reference, and the 10 MHz is modulated onto the 300 MHz. I do not want this to be multiplied to 15 GHz. There is a 74lvc163 counter that is visible as well. (100/10 = 10 MHz) The PLL chip is a 74lv4046, the phase comparator part. When the reference is != 10 MHz and the prescaler is running, OMG, grass like on an African steppe. Only the zebras are missing. Without ext ref: sx3fQ8.png I don't think that the VCXO has thus a large modulation bandwidth and I'd like to replace the 4046 with a 9046, but I've found no way to switch off its internal oscillator. Having not-vanishing loop gain at lock is fine, but getting the 8046's undefined on-chip VCO on the output spectrum would be no improvement. Any ideas? Cheers, Gerhard p.s. How can the spectrum analyzer (89411A) encode such sharp screen dumps in just 3 KB? <100MHz_from 2 * lvc125.png><300mhzmal2-sky17.png>___ 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. ___ 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: Trimble Thunderbolt- Frequency lock indicator
Probably more than you want but ... < http://www.ko4bb.com/getsimple/index.php?id=the-new-thunderbolt-monitor-kit> -Original Message- From: Wojciech Tomczyk via time-nuts Sent: 19 February 2022 12:07 To: time-nuts@lists.febo.com Cc: Wojciech Tomczyk Subject: [time-nuts] Trimble Thunderbolt- Frequency lock indicator I use an early Thunderbolt as a 10 MHz external frequency standard for my Elecraft K3 transceiver.I would like do add to it a simple indicator which is activated when Thunderbolt's output frequency is locked.I someone aware of a circut diagram of a such indicator? Any other options to indicated the LOCK state? Tom ___ 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.
[time-nuts] Re: Garmin GPS 25 Module
I have a number of Garmin GPS35s which are the same engine in a mouse package. They are still working and do not have the roll-over problem because they can be programmed with the current date and time if need be (I wish Trimble had done this with the Thunderbolts). The NVRAM can get corrupted and may take a while to reset. I also have a procedure I got from Garmin to clear it if it does not take care of itself. David N1HAC On 2/9/22 10:57 AM, Andy Talbot wrote: Yes, I had to disable the GSV sentence to get the data flow down to a level that could be sent at the lower speed. I'm only using GPRMC, so all the others could be removed as well, but as GPRMC comes first in the block every second, there's nothing to be gained from killing any of the others sentences. I did fall foul once of a changed format. Originally I wrote for an RMC string that just gave integer seconds. On using my code with a later module it failed, and I spotted that it was sending decimal seconds, so had to rewrite my PIC code to cope with that. Then later, using other module types, GPRMC became GNRMC to cope with Glonass etc. so that was another change needed. Andy https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.g4jnt.com%2Fdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C4d1fde6e4e5847e5ef7608d9ebe686f2%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637800197633061750%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=EEF8lAjyACwHRvSDDZG0lyW6w%2BZPBJcJuqZeZ6Jrt8s%3Dreserved=0 On Wed, 9 Feb 2022 at 15:49, Bob kb8tq wrote: Hi In terms of upgrading the GPS module(s): You might want to look at just *what* NMEA messages are being used. While the format is “standard” it’s not quite dead nuts in some cases. Vendors get to add this and that and it still is NMEA. Converting from one family to another is not always easy. I would also want to check the GPS antenna at the remote site. They don’t last forever. Flakey sat signals can drive a module a bit nuts. GPS modules have gotten pretty cheap over the years. If this is a long drive / crazy access sort of thing, redundancy is not as expensive on the module (or antenna) side as it once was. Bob On Feb 9, 2022, at 4:36 AM, Andy Talbot wrote: I run a set of microwave beacons on a remote site that transmit data modes whose Tx timing is controlled from GPS. They were installed some 20 years ago and used a Garmin GPS25-LVS module to deliver NMA and 1 PPS signals to all five individual controllers. After a power outage that lasted a couple of days, the beacons fired up but it was clear, after a couple of days timing was corrupted. Each beacon has slightly different controller firmware, and by monitoring the resulting corrupted modulation it could be determined what was wrong.No PPS signal was present - which killed modulation on two of them. NMEA timing data was present but the time being reported was out by several seconds, rendering the data signal transmitted undecodable by most people. I went up to the remote site to recover the old hardware and am in the process of replacing the timing source using a Ublox NEO-6. Since all the beacons were originally designed based on 4800 baud NMEA, the Ublox was set for this for backwards compatibility with the Garmin and the configuration saved in NV ram. Now the query I have. I had assumed it was a 1024 week rollover that killed the Garmin, but on testing teh module when I returned home, after a longer than normal initialisation period it DID start outputting the correct date and time, with PPS present. So the initial reboot failed, even after a couple of days attempt, but after a power cycle it worked. I'm puzzled by that behaviour. Is anyone here familar with the GPS25 family, dating from the turn of the millennium? As an aside, a Jupiter TU60 GPS module was also in use on site, delivering a GPS locked 10kHz signal. This I used to lock a 10MHz reference in "Probably the Simplest GPSDO Possible" https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fg4jnt.com%2FSimpleGPSDO.pdfdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C4d1fde6e4e5847e5ef7608d9ebe686f2%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637800197633061750%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000sdata=WhJg63l8ZeetkN4G%2FbvI6Nx9pi9M3cbFeHXXH%2F4oWQo%3Dreserved=0 That module, which is not a lot newer than the Garmin, did appear to have survived the reboot as the resulting frequencies of the beacons were spot-on when they returned with their modulation faults. However, in the spirit of doing the job properly, it too is being replaced with a Leo-Bodnar mini GPSDO. All beacon details at scrbg.org Andy https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.g4jnt.com%2Fdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C4d1fde6e4e5847e5ef7608
[time-nuts] Re: electronics question or how not to fry my raspberry pi
On 28/01/2022 19:41, folkert wrote: Hi, [] The RPI doesn't like 5v on its GPIO pins. So I wonder: - can I feed the picdiv 5v on its GPIO pin while giving it a 3.3v voltage so that it outputs 3.3v as well to the rpi pins? - or should I use a voltage divider? I was thinking of a 4.7k ohm and 8.2k ohm resistor giving slightly less than 3.2v - will that work? or will that attenuate the signal too much? The 50 ohm bnc cable between the amplifier and the rpi is 3m long. Anything else I should be aware of? Regards, Folkert van Heusden PD9FVH Folkert, In similar circumstances I've used a resistive divider and it's worked exactly as expected. For such short cables there are unlikely to be any other effects you need to take care of. You might like to see what the voltage levels are if you terminate the 50-ohm cable with a 47-ohm resistor - it /may/ drop to 2.5V peak-to-peak. I would simply try it and see. Of course, if the idea is to send PPS to the RPi getting the appropriate GPS devices would be my preferred solution! Oh, just looked, I would expect to see a square-wave, not the near sine-wave your 'scope trace shows. Is it nearer to square with a much faster timebase? Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: Derivation of time from celestial sight
On 27/12/2021 20:18, Brent wrote: My understanding (and I could be wrong) is that one could derive 'stellar' time from a start sight/fix on polaris or another well tracked celestial object. I was once told that early editions of Bowditch provided the process (for the moon I was told) although one of the relatively old edition's that I have doesn't provide it. My previous answer mentioned precision, of course, not accuracy. And the error I mentioned was not the error in GPS which places the zero degree meridian some 102m east of Greenwich! David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: Derivation of time from celestial sight
On 27/12/2021 20:18, Brent wrote: My understanding (and I could be wrong) is that one could derive 'stellar' time from a start sight/fix on polaris or another well tracked celestial object. I was once told that early editions of Bowditch provided the process (for the moon I was told) although one of the relatively old edition's that I have doesn't provide it. Some theodolite manufacturers provided attachments to aid the process (for the high zenith where a theodolite experiences reduced accuracy), and those attachments were dated and calibrated for their year of manufacture and came with tables for use in future years. That's about all I know or can find on the subject. Can anyone here point me to any published literature? Anyone have experience trying? Any idea what type of accuracy can be expected? Got some new toys coming and need something to do with them Brent Brent, You might find something like these of interest: http://www.thegreenwichmeridian.org/tgm/articles.php?article=6 https://www.rmg.co.uk/stories/topics/airys-transit-circle-dawn-universal-day http://www.royalobservatorygreenwich.org/articles.php?article=1087 There is a possibly apocryphal tale that some students at Cambridge did this in the late '60s or early '70s and getting about a second or two accuracy, and discovering that the longitude of the Cambridge Observatory was some hundred metres out. You might find a reference, and I might be mistaken! Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: help reviving Trimble UCCM-LPS GPSDO
I have a couple of Trimble UCCMs. They would not come ready unless pin 39 of the 50 pin ribbon connector is grounded. This selects the 1PPS sync source. Ground is internal, open is external. 73, David N1HAC On 12/24/21 7:39 AM, Wilko Bulte wrote: hi Francois, That EEVblog thread discusses (mainly) the UCCM produced by Symmetricom. If I remember correctly the Symm uses a 12V powered OCXO, likely with another Vref output. I sold my Symm, the two Samsung UCCM I have found to be "just working always". In the meantime I have measured the EFC voltage of the Trimble over a long period (interval 2 sec). Vref is 2.5V, taken from a LM336. In more detail At about 2.5V EFC voltage I measure 10MHz output, plus/minus a couple of mHz. So using a Vref of 2.5V I do get an EFC voltage in the right range. Unfortunately the Trimble never goes GPS locked. LH reports FFOM: Init and Operation mode: Settling. Reported TFOM is 2. No idea why it does not lock, the GPS sees ample sats and is in position lock mode. Ideas welcome! Wilko > On 24 Dec 2021, at 12:41, F1CHF wrote: > > error in the Link ? > is it the good one ? > tks > > > https://www.eevblog <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.eevblog%2F=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C5e368c4bed4442c4c81d08d9c702eb66%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637759637767230002%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000=wItGRmNR%2F%2BipczR5Fu9sMZftMW6mTl4yXMBN22jBVC4%3D=0> > com/forum/projects/a-look-at-my-symmetricom-gpsdo-(ocxo-furuno-receiver)/msg3 > 78499/#msg3778499 > > francois > > > > ---Message original--- > > De : Wilko Bulte > Date : 23/12/2021 20:50:36 > A : Discussion of precise time and frequency measurement > Sujet : [time-nuts] Re: help reviving Trimble UCCM-LPS GPSDO > > > >>> On 23 Dec 2021, at 18:58, Attila Kinali wrote: >>> >>> On Thu, 23 Dec 2021 12:14:48 -0500 >>> Bob kb8tq wrote: >>> >>> It’s a pretty good bet that the Vref is 5V >> >> A quick google lead me to this forum post: >> https://www.eevblog <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.eevblog%2F=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C5e368c4bed4442c4c81d08d9c702eb66%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637759637767239960%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000=pDHdAlHCUGp%2FKIyE21WtGeBpei0yNt6mP0K3XqTWj04%3D=0> > com/forum/projects/a-look-at-my-symmetricom-gpsdo-(ocxo-furuno-receiver)/1325 > >> >> Looks like the Vref is supposed to be 2.5V > > For the Symmetricom UCCM or for the Trimble? > > These UCCM are form-fit-function compatible but that does not mean the > circuits are the same. Or the OcXO. > > Samsung also produced UCCM, of which I have 2, both working fine. Again > different circuits, different GPS etc. > > Wilko >> >> Attila Kinali >> -- >> The driving force behind research is the question: "Why?" >> There are things we don't understand and things we always >> wonder about. And that's why we do research. >> -- Kobayashi Makoto >> ___ >> 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.___ > 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. ___ 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: Poor's man NTP
On 18/12/2021 21:13, giuse...@marullo.it wrote: Hi Bob, If you have a requirement for always being in the microseconds rather than milliseconds, PTP is a better approach. I just need it for logs and computer time sync, PTP seems overkill for my requirements. It is a small lab, then maybe I could offer NTP (SecureNTP) service for the rest of the company, if I will add other NTP/SecureNTP servers depending on the load. Giuseppe Marullo IW2JWW - JN45RQ Giuseppe, If you are considering something for "the rest of the company" you could save yourself a lot of bother by getting something like the LeoNTP box: http://www.leobodnar.com/shop/index.php?main_page=product_info_id=272 https://store.uputronics.com/index.php?route=product/category=70 It just sits there and works, and can serve many thousands of NTP clients. Good luck in finding one, though, due to the current component shortage. 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: Poor's man NTP
On 16/12/2021 23:37, giuse...@marullo.it wrote: Hi, just wondering if a PI4 could be a suitable NTP server for a small lab (and maybe with some other NTP servers for my company, about 2000 clients). Main use is for correct timestamp on logs/computer time sync. I setup the NTP using Adafruit Ultimate GPS shield(with battery), and the GPS/GLONASS Antenna(cheap one, not a timing antenna). Antenna is on a roof window with a small metal base, outside. What is the accuracy I could expect from it? You can see the offsets reported by a number of Raspberry Pi NTP servers here: https://www.satsignal.eu/mrtg/performance_ntp.php As a very rough guide I would expect a PPS-based RPi to be within 100 us easily, and perhaps considerably better (~10 us) in a constant temperature environment, and with no other load. I don't know about load capacity as I've not tested that, but here it's serving perhaps 50 devices. With classic NTP which is what I use there will be a period before the offset becomes near-zero so 24 x 7 is the way to operate. Although there are some devices on that page with LAN, 2.4 GHz or 5 GHz connections, for beat accuracy you must use the PPS signal from the GPS as you know. The "o" tally code suggests that's OK. I suggest using the "pool" directive rather than multiple pool servers: https://www.satsignal.eu/ntp/setup.html#pool Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: PPS latency? User vs kernel mode
On 13/12/2021 21:22, Trent Piepho wrote: And finally we can have the kernel act on the PPS timestamps itself. But NTP network traffic might be a bridge too far. Mills describes this as a "hardpps()". This was added to Linux in 2011 by Alexander Gordeev, based on Mills' work, but with a different implementation. This is a "kernel consumer" of PPS timestamps, which can be used to steer the PLL entirely inside kernel code. It's enabled with the kernel config option NTP_PPS. One can easily see if this is present in the kernel via the usual methods. It is often NOT enabled because it doesn't work with tickless kernels. I do now know if current ntpd supports this or what it takes to use it with ntpd. I have used it, but I wrote my own code from scratch to integrate it with a GPS module to perform time sync without installing either ntpd nor chrony. Trent, Thanks for that! I was only aware of a limited subset of that as I came later to NTP on Linux (it was mostly Windows before), and I understood even less at the time! Your notes helped clarify things, thanks. David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: PPS latency? User vs kernel mode
On 13/12/2021 04:17, Adam Space wrote: What do you mean by "kernel mode"? I am referring to this guide <http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html> that another user here recommended to me a bit ago. I am not too sure myself since I am relatively new to this. That document is now historic background. It refers to the early "kernel mode" when (AIUI) part of the OS rather than NTP did the fine clock adjustment. I recall that early Raspberry PI OS kernels did not include all the functions required for the most accurate timekeeping, and that a kernel recompile was required. Fortunately that is no longer required, and recent OS versions can directly accept PPS pulses, although they no longer include NTP! You may find my current version less confusing: https://www.satsignal.eu/ntp/Raspberry-Pi-quickstart.html although the confusion is now within the different RPi models, mapping the different physical serial ports to the virtual ports, and choosing the ports which don't have a variable clock speed! In Windows we do need to distinguish user/kernel modes, because we used to have kernel mode as a modification of the device driver but it's no longer accessible, and a workaround runs in user space, hence user mode. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: Clock display on Linux systems?
On 05/12/2021 20:53, Adam Space wrote: Most distributions of Linux already have a "clock" application that shows the system time, but I am wondering how to program a more customizable display on a Linux system / Raspberry pi. There are a few solutions that pop up by googling the issue, but these are all insufficient. For example, the only solutions in Python (which I would prefer to use if possible, but not necessary) I have found are 1) using a library like pygame or tkinter to build a display or 2) doing something more barebones like displaying the time and sleep() ing for a second. 1) is terribly inefficient for a display of accurate time, because either you have a refresh rate that is low and the clock updates with significant lag, or you have a high refresh rate which eats up large processing power. 2) is also inefficient because the frequency of a local clock may be poor, so long term accuracy can only be sustained with synchronization via NTP for example. Perhaps there are lower level Linux commands that could be used for this? I'm not sure. Any suggestions are welcome. Adam Adam, I have a simple digital wall clock program for the Raspberry Pi if it's of any help. FreePascal/Lazarus both source and executable available: https://www.satsignal.eu/raspberry-pi/DigitalClock.html Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: NTP Leap indicator set to 1 ! problems continue
I can see a handful of them in my ntp leap second monitoring data. https://www.maths.tcd.ie/~dwmalone/time/leaps/ntp2021Nov-leapbits.png The regular data for June and December is here: https://www.maths.tcd.ie/~dwmalone/time/leaps/ David. ___ 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: Leap indicator set to 1 !
On 27/11/2021 15:22, Steven Sommars wrote: FYI. At 2021-11-27 00:00:00 UTC many public NTP servers began setting the leap indicator to 1. This may be gpsd related Yes, I see it on [possibly] one of my ISP's servers: cpc137586-lock4-2-0-cust263.6-1.cable.virginm.net 86.3.245.8 I wrote a little (Windows) program to check this. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: QM10 Quartz chronometer
But not in a chronometer. They usually use something in the MHz range. 32kHz crystals are not very stable over temperature. Watches rely on you wearing it for much of the day, keeping it at a nearly constant temperature and putting it on your bed stand at night, also presumably fairly constant. Unfortunately they have been adopted for computer Real Time Clocks, which is why most computers do not keep very good time. David N1HAC On 11/26/21 9:14 AM, Scott McGrath wrote: Usually in analog quartz clocks oscillator frequency is around 32khz Content by Scott Typos by Siri On Nov 26, 2021, at 9:09 AM, Peter Torry via time-nuts wrote: Hello list, I am restoring a Seiko Quartz QM10 Marine Chronometer that is currently inoperative. Preliminary investigations would indicate that the oscillator (TO5 header) isn't functioning therefore I am seeking any information as to its nominal frequency and whether it is just a crystal or an oscillator. I can follow the cmos dividers OK but a schematic diagram would be most useful. Any help or pointers much appreciated. Kind regards Peter UK ___ 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. ___ 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: List Opinion/Suggestion(s)
On 25/11/2021 08:14, Hal Murray wrote: (according to a pre-configured compile-time constant), Have you looked at the tinker stuff in the config file? I'd expect it to be there. I don't see it in there, Hal. David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: List Opinion/Suggestion(s)
kb...@n1k.org said: I would strongly suggest that with NTP ???more is better???. Three reference devices is about the minimum. Five is a good target to aim for. One suggestion I make to folk who ask is to use the "pool" directive. This allows NTP to choose as many servers as it needs (according to a pre-configured compile-time constant), and it will automatically drop and add servers as needed. OK, it's a little more complicated than that but using pool is easy: Replace the lines: # Use pool NTP servers server 0.uk.pool.ntp.org iburst server 1.uk.pool.ntp.org iburst server 2.uk.pool.ntp.org iburst with the single line: # Use pool NTP servers pool uk.pool.ntp.org iburst if you are in the US, for example: # Use pool NTP servers pool us.pool.ntp.org iburst and you can use multiple lines such as a Dutch user might have: # Use pool NTP servers pool nl.pool.ntp.org iburst pool uk.pool.ntp.org iburst See: https://www.satsignal.eu/ntp/setup.html#pool Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: NTP servers
On 22/11/2021 02:29, McFail Troll wrote: Hi all, I am new to the mailing list, and pretty new to timing stuff in general. I wanted to ask if any of you folks who have a more advanced set-up (synchronization via gps/radio, or just a well working rubidium clock or something) maintain a solid stratum 1 NTP server. Of course, I am aware that there are plenty of good stratum 1 NTP servers open to the public (e.g. NIST's servers), but I am curious to see if I could sync up with some of you guys who seem to have some pretty cool set-ups. Btw, sorry if this has been asked before on this list. Thanks You may find some helpful information on my Web page: https://www.satsignal.eu/ntp/Raspberry-Pi-quickstart.html about using a GPS/PPS device with a Raspberry Pi. This gets you down into the microsecond region at a low cost and a low power consumption - helpful as leaving the device on 24x7 is best. Be aware that many of the public stratum-1 servers are overloaded and perhaps not as good as you might want. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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 09/09/2021 03:36, 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, It sounds as if you live in an area where monitoring of earthquakes would be of interest! If you haven't got something already, you might like to look at the Raspberry Shake: https://raspberryshake.org/ The devices are not at the professional seismograph level. They operate a world-wide network. 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: Query about List and about 10 MHz Distro
On Sun, Aug 29, 2021 at 10:43:51AM -0400, paul swed wrote: > We my only issue is every time we had a lightning storm it seemed to > fry the ICs. While they may not have ideal behavior with temperature (and related phase/group delay changes) the old antique 10Mbs era balanced twisted pair ethernet transformer/filter modules did eliminate common mode energy getting into the receivers (and transmitter) which it sounds like was the cause of your lightning EMP problem. For 10 MHz these ought to work pretty well with twisted pairs as they provide galvanic isolation breaking ground loops. Not completely clear what the common mode Z of the things is at 10 MHz... but unless there is a deliberate cap from a center tap to local ground I'd guess it would be significantly high given just winding to winding capacitance. I do certainly beleive that optical transmission is the better solution... however. -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." ___ 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: Comparison/evaluation of u-blox timing receivers
On 24/08/2021 02:51, John Ackermann N8UR wrote: In 2020 I did an extensive evaluation of the timing ability of the u-blox LEA-M8F, NEO-M8N, NEO-M8T, NEO-M9N, ZED-F9P, and ZED-F9T. The work was made possible by support from the HamSci consortium (https://hamsci.org) under NSF grants supporting HamSci activities. I was sure I'd posted about the paper on time-nuts, but I can't find any record that I did, so this is a belated announcement. It's available for download from https://hamsci.org/sites/default/files/publications/2020_TAPR_DCC/N8UR_GPS_Evaluation_August2020.pdf As BobC says, "Lots of fun!" John Most interesting, John, thanks for posting. (Accidentally send directly, sorry.) David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: Thunderbolts ...
I have been using several versions of the UCCM units (Trimble, Symmetricom and Samsung) with mostly good results, both bare and packaged, as well as having several Thunderbolts. The one thing that the Bodinar unit has which is nice is the synthesizer built in. The Thunderbolts and UCCMs do not have this. On the other hand, as has been said, the Bodinar unit has poor hold-over performance if you lose GPS lock, which here in NH amongst the trees and hills can happen fairly frequently. As a result, I use OXCO GPSDOs with an external synthesizer. David N1HAC On 7/20/21 1:32 PM, N1BUG wrote: Good question on the Leo Bodnar comparison. That's what I am using now and I am sure it is good enough for my purposes but I really want something I can use with LH and maybe the KO4BB Thunderbolt Monitor. I also inquired about the Thunderbolts and hope there's enough supply that I can grab one. I've been looking for a while but am hesitant on eBay units. Paul N1BUG On 7/20/21 1:11 PM, Bob Darlington wrote: Same. He probably got 250+ requests in short order. I'm curious how the Leo Bodnar GPSDOs compare. I'm considering one of these over a thunderbolt for field use for ham radio EME work. -Bob N3XKB On Tue, Jul 20, 2021 at 10:59 AM Wes wrote: I wrote Tom, at the address he gave, on Saturday with a query. So far, no reply. Wes N7WS On 7/19/2021 4:59 PM, John Miles wrote: If you're looking for a low cost surplus GPSDO, the ones Tom mentioned in his post on Saturday are the ones you want. Not a Thunderbolt-E, and not something from the China surplus/e-waste market. -- john, KE5FX ___ 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. ___ 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.
[time-nuts] Re: GPS antenna distribution?
On 28/06/2021 21:56, lstosk...@cox.net wrote: Thanks guys. Opened a lot of things to think of. Makes me wonder how I get any results from a north facing window with the UV coating! Will work out something. N0UU Maybe an antenna in the loft might produce better results? Check it with your (Android) phone/tablet which can display the signal strengths. You could consider using something which sticks to the outside of the window if the attenuation is too great? Cable through a small hole, or where the window opens? 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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: 2nd Run of TimeHats
I would take 2 also. Thanks, David > On May 1, 2021, at 11:10 AM, Bill Notfaded wrote: > > I'd be interested in 2 too. > > Bill > >> On Wed, Apr 28, 2021, 4:10 AM Michael Gindonis >> wrote: >> >> I would be interested in at least one, perhaps even 2. and perhaps bare >> boards. >> >> Some things that if not already considered, could make it more interesting >> than it already is: >> >> - possibility to have a 26 pin connector instead of the 40 pin connector >> would be nice for use on Pi 1B. ( or just an option for unsoldered >> connector and one can solder it oneself.) >> - bare board with breakout connections for RTC and GPS modules, a >> CR2032 holder... this could make the bare board handy as time-nut oriented >> protoboard to use with other modules. >> - extra pads opposite GPIO side of board to mount a couple extra SMA >> connectors. ( using proto space one could add one a buffered PPS out or >> other timepulse out ) >> - MAX-M8W with active antenna out. >> >> I have been lurking on this list for a while. A minor upgrade to my low >> budget ntp server is long overdue. Have used Aliexpress RTC modules with >> the Pi ( with modifications to use a CR2032 safely). I have also had a few >> Pis running with nearly 20 year old surplus fastrax GPS modules which >> include a patch antenna. Just a protoboard, jumpers, sometimes a backup >> battery and some DIP switches for setting modes. I had started a GPS board >> design in KiCAD a while ago but got bogged down when trying to layout the >> traces for the antenna connector according to the module manufacturer's >> recommendations. >> >> At the moment I just one running GPS ntp server on an old Pi 1B. The module >> I use works well most of the day. Having a patch and no external antenna >> connector the whole module must be exposed to sunlight. The module doesn't >> adjust it's TXCO offset if it doesn't have a GPS fix so it may drift a bit >> on sunny days. >> >> Name/IP AddressNP NR Span Frequency Freq Skew Offset Std >> Dev >> >> == >> NMEA8 7 224-17.321 8.039+55ms >> 238us >> PPS61 36 240 -0.000 0.003 -0ns >> 414ns >> ftp.mikes.fi 19 13 310m -0.050 0.010 +1718us >> 64us >> ntp.netnod.se 15 9 241m -0.046 0.044 +1596us >> 183us >> time.cloudflare.com49 26 13h -0.099 0.013 +2935us >> 372us >> ivanova.ganneff.de 14 9 224m -0.045 0.025 +3083us >> 79us >> >> Best regards... >> >> ...Mike >> --- >> Michael Gindonis >> >> >> >> On Mon, Apr 26, 2021 at 7:58 PM John Miller via time-nuts < >> time-nuts@lists.febo.com> wrote: >> >>> Hello everyone, >>> >>> I’ve seen a number of messages lately that reference the TimeHat boards I >>> put together a couple of months ago, with lots of positive feedback, >> which >>> I really appreciate. The first run of boards I did sold fairly quickly, >> and >>> based on a number of emails I have gotten lately there seems to be some >>> renewed interest. >>> >>> As such, I’m going to order up another batch of PCBs and parts, but I’d >>> like to get an idea of how many I need to order to satisfy current >> demand. >>> The GPS modules come from China, so there is about a two or three week >> wait >>> them, so I want to make sure I have enough. >>> >>> For those not familiar, you can learn more about the TimeHat here: >>> https://millerjs.org/timehat >>> >>> Regards, >>> John >>> ___ >>> 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. ___ 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] Raspberry Pi GPS/PPS/RTC HAT
For UK (and perhaps European) enthusiasts, if the import duty, VAT and collection fee is too great, you might like to look at: https://store.uputronics.com/index.php?route=product/product=60_64_id=81 I hope this is OK to post, but since Brexit buying anything from outside the UK is a lottery as to what the final price may be. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Time travel, was Re: Sparkfun lists SA.35m
Speaking of aspirational, for those interested in time travel (that comes under "time nuts", no? ;-) ) there is this: https://www.oreillyauto.com/flux-500.html David N1HAC On 4/3/21 11:10 AM, David Witten wrote: It seems to be aspirational. It has been on the SparkX page for a long time now. Dave Date: Sat, 03 Apr 2021 07:15:13 + From: "Poul-Henning Kamp" Subject: [time-nuts] Sparkfun lists SA.35m To: Discussion of precise time and frequency measurement Message-ID: <81790.1617434...@critter.freebsd.dk> Content-Type: text/plain; charset="us-ascii" I know it's not a particular outstanding atomic clock, but I was still surprised to see that Sparkfun lists the SA.35m for $1995... https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.sparkfun.com%2Fproducts%2F14830data=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C4b95cfe1ab1d4dd16a9908d8f6b2d120%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637530595160825064%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=IWKhFZl8W%2BjRAMdcIMfBcTArNXyYXZtndC6XcQseLT4%3Dreserved=0 Not in stock though... -- 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@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.
[time-nuts] Re: Sparkfun lists SA.35m
It seems to be aspirational. It has been on the SparkX page for a long time now. Dave > Date: Sat, 03 Apr 2021 07:15:13 + > From: "Poul-Henning Kamp" > Subject: [time-nuts] Sparkfun lists SA.35m > To: Discussion of precise time and frequency measurement > > Message-ID: <81790.1617434...@critter.freebsd.dk> > Content-Type: text/plain; charset="us-ascii" > > I know it's not a particular outstanding atomic clock, but I was still > surprised to see that Sparkfun lists the SA.35m for $1995... > > https://www.sparkfun.com/products/14830 > > Not in stock though... > > -- > 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@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: WWVB Daylight savings
On Sun, Mar 14, 2021 at 07:43:03PM -0700, lmcdavid wrote: > I have 3 WWVB AM clocks that did not update DST overnight last night > but one that did and two BPSK clocks that did. Par for the course. The > BPSK clocks always set correctly within 10 minutes any time of day.I My 4 BPSK clocks updated just exactly as they are supposed to - my wife was most amused to watch the process at 2 AM on the one in her sewing room/home office. She actually asked to be woken up to see it. I'm pretty sure the SW in the clock needs only to get a valid message about the pending change time some point in advance ... but those BPSK clocks work well in the Boston suburbs, which is not exactly strong WWVB 60 KHz territory... though they are in a wood frame house and a brick hospital office... not particularly magnetically shielded either place. > Original message From: lstosk...@cox.net Date: 3/14/21 7:23 > PM (GMT-08:00) To: time-nuts@lists.febo.com Subject: [time-nuts] WWVB > Daylight savings Strange, here in KS one of my 60 kHz clocks didn't update.?? > I'll give it a few days and not blame the update.?? > N0UU___time-nuts mailing list -- > time-nuts@lists.febo.com -- To unsubscribe send an email to > time-nuts-le...@lists.febo.comTo 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. -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." ___ 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] NPL courses on time and frequency measurement
It looks like NPL are in the process of creating some courses on this. Introduction to Time and Frequency Measurement https://elearning.npl.co.uk/enrol/index.php?id=53 I think I read something on the NPL site to imply that was free, but I can't see that now. Anyway, it's not available yet, but it is obvious they intend producing some courses. ___ 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] U-blox F9T performance (was: U-blox teaser)
On 01/03/2021 00:52, Thomas Abbott wrote: Hello Time Nuts, first post from a long-time lurker. In late 2019 I evaluated the Ublox F9T for a project. Here is a graph of the time difference between PPS outputs of two RCB-F9T boards on the bench. Each had a U-blox dual-band ANN-MB-01-00 antenna, they were 1 metre apart, on ground planes, with excellent sky view. [] Thomas Any chance of adding X and Y scales to the graphs? David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Fwd: PLL book 3rd edition
Microwave and Wireless Synthesizers: Theory and Design, Second Edition by Ulrich L. Rohde (Author), Enrico Rubiola (Author), Jerry Whitaker (Author) Is now available for preorder on Amazon, with a scheduled availability date of May 11, 2021. I've preordered my copy, looking forward to it. On Fri, Aug 18, 2017 at 8:17 PM KA2WEU--- via time-nuts wrote: > > well,that is a good question. Knowing the publishing industry a yea after > submission of the manuscript , so end of 2018 if we pull our act together > ... > > > In a message dated 8/18/2017 6:31:37 P.M. Eastern Daylight Time, > wb4...@wb4gcs.org writes: > > When will it be available?? > > Jim > > wb4...@amsat.org > > > > On 8/18/2017 4:17 PM, Dr. Ulrich L. Rohde via time-nuts wrote: > > Yes, and there is a lot of useful material in place including CMOS and > related new topics and update on numerical controlled oscillators . Thanks, > Ulrich > > > > Sent from my iPhone > > > >> On Aug 18, 2017, at 2:58 PM, David Bengtson > wrote: > >> > >> That's good news. It would be good to have a single reference for noise > correlation. > >> > >> Dave > >> > >>> On Tue, Aug 15, 2017 at 7:04 AM wrote: > >>>Good Morning all , > >>> > >>> yes , it became non trivial but Enrico agreed to take over the old > chapter 2. He thinks I do not use IEEE norm abbreviation and the noise > correlation part did not exist 20 years ago.And many new and important > things So > I thing we are settled. > >>> > >>> Thanks, Ulrich > >>> > >>> In a message dated 8/14/2017 9:10:45 P.M. Eastern Daylight Time, > david.bengt...@gmail.com writes: > >>> Ulrich - Did anyone ever agree to help update this? > >>> > >>> Regards > >>> > >>> Dave > >>> > >>>> On Fri, Mar 11, 2016 at 3:13 PM, KA2WEU--- via time-nuts > wrote: > >>>> > >>>> Why don't you look at the outline to determine what might be needed > or > >>>> missing . > >>>> > >>>> Ulrich > >>>> > >>>> > >>>> > >>>> > >>>> In a message dated 3/11/2016 11:09:51 A.M. Eastern Standard Time, > >>>> att...@kinali.ch writes: > >>>> > >>>> Hoi Ulrich, > >>>> > >>>> On Mon, 7 Mar 2016 19:52:58 -0500 > >>>> KA2WEU--- via time-nutswrote: > >>>> > >>>>> I have published the following book > >>>>> > >>>>> " Microwave and Wireless Synthesizers: Theory and Design, Ulrich L. > >>>> Rohde, > >>>>> John Wiley & Sons, August 1997, ISBN 0-471-52019-5." > >>>> [...] > >>>>> As I am more or less now in microwave technology and less in PLL > IC's, > >>>> I > >>>>> hate to see this standard textbook disappear Who can help or > want > >>>> to > >>>>> take over? > >>>> Da ich sowieso für mich was grösseres über Zeit/Frequenzmessung > >>>> amzusammenstellen bin, und da PLL's grundsätzlich auch dazu gehören, > >>>> wäre ich interessiert. Mein Problem dabei ist, dass ich von der > >>>> praktischen Seite aber kaum eine Erfahrung habe und für mich alleine > >>>> die Arbeit mit ziemlicher Sicherheit zuviel wäre. Aber es wäre > möglich, > >>>> dass ich zum Beispiel mit Magnus zusammen und vielleicht der Hilfe > von > >>>> ein paar anderen time-nuts und/oder Enrico etwas auf die Beine stellen > >>>> könnte. > >>>> > >>>> Was wären denn die Dinge, welche für dich, in ein Update rein > müssten? > >>>> > >>>> Gruess aus Saarbrücken > >>>> > >>>> Attila Kinali > >>>> > >>>> -- > >>>> It is upon moral qualities that a society is ultimately founded. All > >>>> the prosperity and technological sophistication in the world is of no > >>>> use without that foundation. > >>>> -- Miss Matheson, The Diamond Age, Neil Stephenson > >>>> ___ > >>>> time-nuts mailing list -- time-n...@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-n...@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > ___ > time-nuts mailing list -- time-n...@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-n...@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@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] Old Crystal.
Stamp on the top is 1000 kHz in Russian. David N1HAC On 2/28/21 6:35 PM, Dan Kemppainen wrote: Hi All, I've picked up a couple of old crystals. Mostly because they look neat. They are 1Mhz, in a glass tube. The quartz is ~25mm dia, at about 1 mm thick. Was able to get them to oscillate using a Colpitts circuit. They will oscillate at 2.851Mhz (probably some strange mode) if given the chance. I've been scouring my reference books here, and haven't had much luck finding any details on how one would even guess at the parameters of a quartz like this. There area few numbers on them, 33 stamped on the side, 1000 (KHz???) on the top, 87 on the top, and hand written 501 (probably a SN). Digging on line, I'd guess an AT cut based on thickness. I'm guessing the 33 is capacitance in pF. 87, might be year. If any of you have any suggestions on where to find information on how to get something like this to oscillate properly, guess at correct parameters, or even measure any of the parameters I would really appreciate it. I'm sure these are really nothing special, but it would be neat to give them a fighting chance to show what they can or can't do without breaking them! Thanks, Dan ___ 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.
Re: [time-nuts] Mains Frequency
IIRC the requirement used to be that it was correct averaged over 24 hours. I think the Europe wide rules go like this: 1. In the short term (seconds to hours), several mechanisms are employed that continuously try to keep the frequency as close as possible to 50. Hz, but that do not consider the phase (i.e., clock error). 2. So long as the deviation between the true time and the time indicated by a mains-driven clock is less than 20 seconds, observed at 08:00, no further measures are taken. 3. When the deviation exceeds 20 seconds, a correction is scheduled: during the next day (from midnight to midnight) frequency regulators in the entire zone will be set to 10 mHz higher or lower than the normal 50. Hz. Ideally, this results in a correction of 17.28 seconds. 4. The above should normally keep the deviation within about 30 seconds. Only if the deviation exceeds 60 seconds are larger corrections than 10 mHz allowed. That may however be out of date. David ___ 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] Raspberry Pi 4 oscillator replacement
On 04/02/2021 10:20, Avamander wrote: Hi, I was wondering if anyone here has replaced the 54 MHz oscillator on the Raspberry Pi 4 with a GNSS-disciplined rubidium standard? An overkill upgrade, but is technically doable? What hardware would it take in addition to a GNSS-disciplined rubidium standard and a Pi 4? Here's where I got my inspiration from, someone replacing the oscillator on a Pi 3 with a TXCO: https://raspberrypi.stackexchange.com/questions/74482/switch-out-the-x1-oscillator-on-a-rpi-2-3 Yours sincerely, Avamander I would likely use one of these: http://www.leobodnar.com/shop/index.php?main_page=product_info_id=301 Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Radio Controlled Clocks
A clock that uses an NMEA stream for its display will be a few hundred milliseconds slow, dependent on the chosen data products and serial baud rate, as NMEA gives the time of the previous second mark. David N1HAC On 12/27/20 9:54 AM, Andy Talbot wrote: I've just had a look around the house, and actually have four MSF clocks and an old wristwatch minus its strap (antenna is a small ferrite rod inside). Forgot I had an old Junghans one as well - that is sitting out in the shed as it requires a stronger signal than the more modern ones, and seems to get better reception out there. It's the only one that shows MSF outages as it updates every hour - and the battery seems to last forever! I never checked to see how close that is to GPS; if they implement proper timing or just a simple delay bodge. Andy https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.g4jnt.com%2Fdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C34fd0d2e9a8748b929c308d8aa797df9%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637446786072625838%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=r8oYhRkOXFHfKDTdTxlt6y7uaLhSs2IOJAKybbH8Xsk%3Dreserved=0 On Sun, 27 Dec 2020 at 14:02, Peter Vince wrote: Hello Andy, I have an old Maplin digital LCD clock for MSF, and that is always about a second slow, but the Coopers analogue clocks are MUCH closer, as is the Junghens DCF digital LCD clock. But the Junghens DCF clock always misses one or other of the DST changes! Peter On Sun, 27 Dec 2020 at 12:11, Andy Talbot wrote: With this talk of Radio Controlled clocks... I have three domestic RC clocks here, receiving the UK 60kHz signal, MSF. However, I notice that when compared against a GPS clock, timed from the 1 PPS signal & NMEA output, they all are a few hundred milliseconds fast, ie the display changes just before the GPS derived time. ... ... I only ever have digital display clocks, so wouldn't know if the same happens with round ones with hands.Anyone else using domestic MSF or DCF77 clocks who have observed this? Andy https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.g4jnt.com%2Fdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C34fd0d2e9a8748b929c308d8aa797df9%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637446786072625838%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=r8oYhRkOXFHfKDTdTxlt6y7uaLhSs2IOJAKybbH8Xsk%3Dreserved=0 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C34fd0d2e9a8748b929c308d8aa797df9%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637446786072625838%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=wzkD9rJQh3N0lDangtmH6sNwvGhf39xOJrq163myhvw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C34fd0d2e9a8748b929c308d8aa797df9%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637446786072625838%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=wzkD9rJQh3N0lDangtmH6sNwvGhf39xOJrq163myhvw%3Dreserved=0 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] FS: Agilent/HP 5372A
In the Kenilworth, UK ... I have a working 5372A for sale. Collection preferred, but can ship if necessary. Sensible offers OFF list please. David ___ 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] Frequency Counter Choice
Several USB--GPIB designs may be found on the web, for example, https://github.com/fenrir-naru/gpib-usbcdc/ I chose this one because it uses the bus driver chips, rather than driving the bus directly with the microporcessor. It uses a http://www.silabs.com/products/mcu/8-bit/c8051f38x/Pages/c8051f38x.aspx microprocessor, and SN74ALS160, and SN74ALS162 bus driver chips. It includes source code and a (quite small) PC design, in Eagle. I've built this, with PC design modified to use a 32LQFP package. It works, at least for the simple use cases I've tried. David On 2020-11-08 15:51, Ben Bradley wrote: > On Fri, Oct 23, 2020 at 9:14 AM jimlux wrote: > >> ... >> to be set - for instance, Arduinos work that way: >> >> digitalWrite(pin#, HIGH) >> >> I think GPIB would still work if you had to do 8 digitalWrite() calls, >> then a final digitalWrite() call to assert DAV. >> >> I suspect that for a number of Arduino type processors, there is a way >> to write or read all 8 at once, assuming you were clever enough to pick >> the right pins to use. > > It's easy once you figure out which I/O ports you're using. I traced > the AVR pinout and Arduino Mega 2560 schematic to translate between > AVR ports and Arduino I/O pin numbers and to find the port I wanted to > use. Googling found the port names that you can directly read from and > write to in Arduino C/C++ code, as opposed to using the digitalwrite > function for each bit. Here I used DDRC and PORTC: > http://blog.freesideatlanta.org/2017/02/a-capacitive-touch-janko-keyboard-what.html > > ___ > 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.
Re: [time-nuts] OCXO housings - Why copper and not iron/steel?
On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba wrote: > My bad... copper is the second, losing only to silver, as a thermal > conductor. > I think you are mistaken. Copper is second to silver for *electrical* conductivity, but I doubt that is so for thermal conductivity. I think diamond, which is a form of carbon, is the best thermal conductor, and around 5x better than copper. Dave -- Dr. David Kirkby, Kirkby Microwave Ltd, drkir...@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom ___ 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] "When you google word ..."
I am not sure why they would be discouraged. We have known of the gravitational red-shift for a while and it is of course part of GPS calculations. The Mossbauer effect, which involves a very narrow nuclear resonance, was used to demonstrate it in 1959 over a height of 22.5 meters (the Pound–Rebka experiment). It is cool that we now have clocks accurate enough to detect changes of the order of meters and getting better. David N1HAC On 10/29/20 10:32 PM, The Fiber Guru wrote: I actually had the privilege of hearing David Allan present his theories in the yearly NIST conference in Boulder. Interesting fellow. One thing that was pretty cool is that NIST developed a fountain clock that is so accurate it is influenced by altitude. They had to raise the clock once to install a new floor beneath and when they raised the clock it impacted the frequency. Originally discouraged by this it suddenly occurred to someone that they had developed an extremely accurate way to measure height! Now they just have to miniaturize it and make it affordable (of course this is the bane of laboratory experiments). I was once Dir of R at a fortune 50 electronics firm and love hanging out in labs like NIST. db On Oct 29, 2020, at 7:00 PM, cdel...@juno.com wrote: Also when you google "alien deviation" you get: About 11,800,000 results (0.50 seconds) Cheers! :>) Corby ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C03a259293cba4ea053fa08d87c972156%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637396335842396167%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=FXnhIupj%2B1CMSCoP6T%2FOsbYfXqxbG%2FrHWQBZL8wGwgo%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C03a259293cba4ea053fa08d87c972156%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637396335842396167%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=FXnhIupj%2B1CMSCoP6T%2FOsbYfXqxbG%2FrHWQBZL8wGwgo%3Dreserved=0 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.
Re: [time-nuts] WWVB/Anthorn Re: time-nuts Digest, Vol 195, Issue 27
Note that WWVB is 60kHz, not 65kHz. David N1HAC On 10/18/20 10:35 AM, paul swed wrote: Andre you can add layers of litz wire. You actually have litz wire? Thats hard to find these days. But it most likely will need to be more than a few layers. I would slip to small pieces of cardboard on both sides of the existing coil (glue in place) and then fill with the new wire. Check the L every 5 layers. May guess you need 10. But what you want to do can be done. Regards Paul WB8TSL On Sun, Oct 18, 2020 at 5:54 AM Andre wrote: Hi folks. Just a quick question, but I found a small AM/FM radio here (50p!) with a tiny ferrite rod. Wonder what it uses to set the frequency for AM range? Surely not a tuning diode like MV1404 as these are incredibly expen$ive. Was wondering about pulling the rod and modifying it for WWVB as my existing radio clock works and it would be a shame to mess that up. Should be easy enough as I have (somewhere!) a working LCR meter so can wind a suitable winding over the existing one if its too far off or simply add a couple of layers of Litz wire to approximate the required 65 kHz WWVB. I'd also need to locate a 65 kHz quartz crystal for the XT2 position. External antenna might be better here as it would be very weak indeed being from the USA but there's a couple of methods I can use to improve this like using an optical relay from multiple locations at equidistant points. thanks! Andre From: time-nuts on behalf of time-nuts-requ...@lists.febo.com Sent: 17 October 2020 23:02 Teference to match the DUT. But if you do want to mix both the REF and DUT channels, wouldn't it be better to use a single source to drive both mixers? John On 10/17/20 8:59 AM, Gerhard Hoffmann wrote: I'm trying to make a quick frequency extender for a timepod. MCL PSC2-1 power divider, 2* SRA-1 7 dBm ring mixer, 2 DIL 80 MHz-oscillators ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Ccd7a228fe7184e57af7708d873889e59%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637386377892631238%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=jhjMdQ2x%2BgnogUpucLefUkW7PMa%2FwCa6u41wqegWATY%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=04%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Ccd7a228fe7184e57af7708d873889e59%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637386377892631238%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000sdata=jhjMdQ2x%2BgnogUpucLefUkW7PMa%2FwCa6u41wqegWATY%3Dreserved=0 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.
Re: [time-nuts] Symmetricom XPRO rubidium
What about using a the hot-air gun technique to migrate the Rb from the walls of the lamp back to the well? David -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob kb8tq Sent: 28 September 2020 14:23 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Symmetricom XPRO rubidium Hi > On Sep 27, 2020, at 10:19 PM, Stewart Cobb wrote: > > I have a Symmetricom* XPRO rubidium which appears to be reaching its end of > life. The very sparse manual says that it sets a "service" flag when the > lamp voltage reaches 600 mV. When I got it, that parameter was at about > 540. Several months of continuous runtime later, it's down to about 510. I > assume this is a measure of light emitted by the lamp, but its label is > "lamp voltage". > > I don't want to lose this Rb, because it seems to be the most stable > reference in my lab (about 2x more stable with temperature than a PRS10, by > eyeball). > > Questions for the hive mind: > > (1) Why and how is the lamp voltage falling? What's the wear-out > mechanism? It’s looking at the photo detector on the physics package. The amount of light getting to the photo detector is “getting low”. Once it gets low enough, the SNR degrades. At some point that gets bad enough for the device to loose lock > > (2) Is there any hope of repair? Will the heat gun trick for the LPRO work > on the XPRO? Could I replace the XPRO lamp bulb with one from a young LPRO? The devices are “aligned” to match up with the bulb. The various tweaks to get that done are never documented on the Telecom Rb’s. You might get lucky, you might not. If you have a working LPRO, there’s no real reason to expect the XPRO to work any better than the LPRO ( at least not after surgery ….). > > (3) Has anyone ever done surgery on an XPRO? Any hints or tips? > > (4) Does anyone know anything more about the XPRO? I have data sheets > 900-00542-000B and -000F, and manuals 098-00058-000 rev A and rev B. The > manuals are just barely sufficient to get the thing running. The device > itself displays parameters on its serial interface which appear to be > adjustable but which are not described in the manual. Sparse manuals are pretty much the way things are done these days. That’s not just an issue on Rb’s … Best approach is to start shopping ….. Bob > > Thanks in advance for any help. > > *Symmetricom has been acquired at least twice since this device was built. > But the device label says Symmetricom, and the manual says Symmetricom, so > I'll stick with that name for now. > > Cheers! > --Stu > ___ > 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.
Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz
I had to change from my "Marine Standard" 3 ft whip and preamp to a small loop antenna and high-gain preamp, but am getting the signal in a lot of noise and spherics in NH such that an Austron 2100F is locking. There is a big difference between 1MW from Nantucket and 75kW from New Jersey! David N1HAC On 8/14/20 5:52 PM, Dana Whitlow wrote: Thanks, Paul. Does this "standard marine preamp" have an integrated antenna of some kind? If not (or you're not using it), can you tell me about the antenna you *are* using? I've not "heard" so much as a peep here in south central Texas, but have only looked in the daytime. Is the station transmitting around the clock? I do suffer from an abysmally-high noise level here. But I'm trying to get a handle on whether it's even worth my trying further. Dana On Fri, Aug 14, 2020 at 4:23 PM paul swed wrote: Dana that was 11:29 am when you emailed me. Looking at the 3586 its -49 db now. To your second question I can't really know that. Its a standard marine preamp. Might guess 20-30 db. But its nothing special. Made by a company STS. Classic FET, filter , 2 X transistor design. It would be a bit of a math guess to use the 3586 reading and deduce the actual field strength. Regards Paul WB8TSL On Fri, Aug 14, 2020 at 4:08 PM Dana Whitlow wrote: Paul, What time of day did you measure that signal strength? And what are the characteristics of the "standard marine preamp"? Most importantly, what field strength corresponds to 1000 uV output from it? Thanks, Dana On Fri, Aug 14, 2020 at 12:17 PM paul swed wrote: Hello to the group. The signal is on the air. I have just discovered one of my favorite HP 3586 SLVM has an issue with sensitivity. For reference in Boston on a second 3586 the level is -51db avg. or 1000 uv using a standard marine preamp 6' off the ground. The signal should remain on until the 20th. I think this also points to the funny issue I was seeing yesterday with intermittent signal levels. Darn one more project to the list. Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 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.
Re: [time-nuts] HP 58503A GPS receiver not locking to GPS
On Fri, 14 Aug 2020 at 02:55, Eric Garner wrote: > Have you manually set the date/time yet? > > Last time I powered mine up. I had to update the current time and date and > it locked right up. > > -Eric Yes, I have set time, date, location and antenna height. When I first switched it on a few days ago I didn’t. It gave no information about any satellites at all. Then I set the date and location, and it appears that it is seeing some satellites, in that it’s trying to lock to a few. It has just crossed my mind that I set the time to GPS time, not UTC, although I doubt an 18 s error is going to be significant, but I can reset the time to UTC. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkir...@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom ___ 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] HP 58503A GPS receiver not locking to GPS
12 ___ Time PRN El Az PRN El Az UTC 19:43:25 [?] 13 Aug 2020 2 27 228 *26 -- --- GPS 1PPS Invalid: not tracking 5 63 284 *27 -- --- ANT DLY 0 ns 7 62 81 *28 -- --- Position 9 29 83 *29 -- --- MODE Hold 13 29 262 30 65 165 *25 -- --- *31 -- --- LAT N 51:39:04.128 LON E 0:46:36.375 ELEV MASK 10 deg *attempting to track HGT +46.29 m (MSL) HEALTH MONITOR . [ OK ] Self Test: OKInt Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK E-113> ? E-103> *CLS scpi > :system:status? --- Receiver Status --- SYNCHRONIZATION ... [ Outputs Invalid ] SmartClock Mode ___ Reference Outputs ___ Locked TFOM 9 FFOM 3 Recovery 1PPS TI -- Holdover HOLD THR 1.000 us >> Power-up: GPS acquisition Holdover Uncertainty Predict -- ACQUISITION .. [ GPS 1PPS Invalid ] Tracking: 0 Not Tracking: 12 ___ Time PRN El Az PRN El Az UTC 19:56:10 [?] 13 Aug 2020 * 1 -- ---7 58 72 GPS 1PPS Invalid: not tracking 2 22 224 * 8 -- --- ANT DLY 0 ns * 3 -- ---9 24 86 Position * 4 -- --- *10 -- --- MODE Hold 5 68 273 13 34 265 * 6 -- --- 30 69 155 LAT N 51:39:04.128 LON E 0:46:36.375 ELEV MASK 10 deg *attempting to track HGT +46.29 m (MSL) HEALTH MONITOR . [ OK ] Self Test: OKInt Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK scpi > :system:status? --- Receiver Status --- SYNCHRONIZATION ... [ Outputs Invalid ] SmartClock Mode ___ Reference Outputs ___ Locked TFOM 9 FFOM 3 Recovery 1PPS TI -- Holdover HOLD THR 1.000 us >> Power-up: GPS acquisition Holdover Uncertainty Predict -- ACQUISITION .. [ GPS 1PPS Invalid ] Tracking: 0 Not Tracking: 12 ___ Time PRN El Az PRN El Az UTC 20:02:13 [?] 13 Aug 2020 2 19 223 13 36 267 GPS 1PPS Invalid: not tracking 5 69 267 *14 -- --- ANT DLY 0 ns 7 56 69 *15 -- --- Position 9 22 88 *16 -- --- MODE Hold *11 -- --- *17 -- --- *12 -- --- 30 71 148 LAT N 51:39:04.128 LON E 0:46:36.375 ELEV MASK 10 deg *attempting to track HGT +46.29 m (MSL) HEALTH MONITOR . [ OK ] Self Test: OKInt Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK scpi > Dr David Kirkby Ph.D C.Eng MIET Email: drkir...@kirkbymicrowave.co.uk Web: https://www.kirkbymicrowave.co.uk/ Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT. ___ 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] eLORAN will be on the air GRI 99600
Hi Paul, Is Wildwood transmitting now or will they be? I am not seeing anything in NH. Thanks, David N1HAC On 8/5/20 10:00 AM, paul swed wrote: Hello to fellow time nuts. Warm up those old Austrons. eLORAN out of New Jersey has been on the air intermittently prior to a test run next week. Due to the storm they have lost power and should have it back today or tomorrow. The intention will be on the air operation till the 20th. That's a long run. Nice. Seems the Austron 2100s can be had for reasonable money these days also. Enjoy. Paul WB8TSL ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cac55ba07ba7e44c56e0408d83949707e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637322334868061249sdata=ITxnnUFmF7%2F9U2dn25pwR8upRiBuSg6Uzw49CxxZBMQ%3Dreserved=0 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.
Re: [time-nuts] ! PPS Source
IIRC the Thunderbolt DOES lock its internal clock to the GPS David -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob kb8tq Sent: 13 August 2020 14:39 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] ! PPS Source Hi Here’s the “whole story”, sorry if it repeats things you already know … All GPS modules that I have ever seen use a free running clock. The internal oscillator is *not* locked to GPS. When they want to generate a 1 pps output they drop / add cycles from the the internal oscillator to get it “as close as possible”. That means that you will always have an error in the PPS. Since they *know* this is going on, many devices report this error on a second by second basis. Since the error looks like a sawtooth if you graph it, this is often called “sawtooth correction”. This correction also takes care of “hanging bridges” where the sawtooth stays to one side or the other of “correct” for a long time. Normally when feeding a PRS-10, the sawtooth correction is not used. That results in a degraded pps accuracy. The best GPS module to use in this case is one with a very small sawtooth “window” ( = a fast internal clock). Right now, the Furuno parts are winning this particular race. If you *do* use the sawtooth correction (possibly by feeding a variable delay line chip), then indeed the F9P and F9T will do a much better job. Some numbers: Sawtooth on some older modules can be out around +/- 20 ns On newer parts it might be down around +/-10 ns. On the F9 parts it is +/-4 ns. The Furuno parts run half that. Corrected, on a modern part, and looking at second to second variation, you can get below 1 ns with various modules. On the F9’s you can get well below 1 ns. = All of that is looking at short term variation. Your Rb does not move much short term (unless the temperature changes …). Its stability and aging likely are quite good. GPS (as received / uncorrected ) swings around a bit during a normal day. Swings of 10 to 20 ns are pretty normal. > 50 ns is possible under odd conditions. That’s more than your Rb is likely to move around over a 4 to 12 hour period. If you “follow” GPS with your Rb through a conventional loop, you likely degrade the stability of the Rb. It takes a fairly fancy loop to do a good job on an Rb. Bob > On Aug 12, 2020, at 11:44 PM, Joe Hobart wrote: > > I have been using 1 PPS from a Motorola M-12 timing module to steer a SRS > PRS-10. I recently heard that a U-Blox ZED F9P module receives both L1 and L2 > and can provide much improved positional accuracy. > > Would better positions translate into a smoother 1 PPS? Does anyone have > experience with this U-Blox module? Can this be set up with a fixed position > as > a timing module? > > Is there a better source of 1 PPS at a reasonable cost? The U-Blox is about > $200. > > Thanks, > Joe, W7LUX > > --- > This email has been checked for viruses by AVG. > https://www.avg.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. ___ 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.
Re: [time-nuts] WWVB SDR discussion
On Tue, Aug 11, 2020 at 10:27:33PM -0400, paul swed wrote: > Just saying they work for all those atomic clocks for $10. Those don't give a damn about 60 KHz delay/phase provided it doesn't change very fast (as it wouldn't due to thermal effects). But monitoring frequency or drift of an oscillator by comparing it the 60 KHz WWVB carrier through the filter would show frequency and phase shifts due to the thermal shifts. That would result in false indications of drift and instability and certainly cause issues with anything that depended on deriving exact time to way closer than a second from the signal. (And yes ionospheric shifts are real and of this magnitude too). -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." ___ 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] Austron 2100F/T manual
Would someone be able to send me a PDF of the Austron 2100F manual? I have an F, but would also be interested in looking at the T manual, as well. Thanks. 73, David N1HAC ___ 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] For those following ES100 WWVB receiver modules
The generic WWVB receivers in radio-controlled clocks are essentially TRF receivers using a 60kHz crystal as the tuned element. David N1HAC On 7/22/20 2:26 PM, Hal Murray wrote: tsho...@gmail.com said: I myself did some experimenting with a tuned loop antenna through a 60 kHz crystal bandpass hooked to a ... What is the bandwidth of the WWVB signal? What is the bandwidth of a crystal filter? (or probably, what are my choices, and what do I get if I use a low cost crystal?) ___ 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] Just any counter external reference and discipline mode.
I have an 8640B in the lab. Bizarre instrument. David On 7/13/20 2:57 PM, Richard (Rick) Karlquist wrote: On 7/13/2020 11:34 AM, jimlux wrote: There are also "frequency locked" devices that are not "phase locked" - they essentially discipline an internal oscillator by adjusting its frequency, but not with any sort of phase locked loop. The 8640 famously worked (sort of) this way. The cavity had an extremely limited electronic tuning range, and would only stay in lock for a few minutes before drifting off. It would do this even if you left it on 24/7. The display would then flash, and you had to release the lock button, retune the frequency using the mechanical cavity know, and then push the lock button back in. Are you kidding me? Definitely in the "gee whiz", "because we can", or "too clever by half" category. At least they didn't have the chutzpah to charge $ for this as an optional "feature". The Navy, recognizing that this was not sailor proof, had the feature/bug omitted from the military version. Good for them. Rick ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C9afb4f70d6bc4b0ad52508d8275fd4c3%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637302639872214633sdata=hktXOKkryvi2YDC3YulE4RNXZDaeHyA87SkCcHN5ekU%3Dreserved=0 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.
Re: [time-nuts] Raspberry Pi NTP server
From: Steven Sommars [] Why bother with GPS/USB? Sometimes I use laptops. Few laptops today directly support PPS/serial. I just checked with Dell and found zero laptops with native RS232. Thanks for posting your measurements, Steven. If you can find a laptop with a direct Ethernet LAN connection you may find that's quite good if (and it's a big if) you have a stratum-1 Ethernet source available. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Raspberry Pi NTP server
David, I've seen your comparison in the list archives. However, none of the approaches I have seen published so far (including yours) exploit all the possibilities I mentioned. The Raspi having better community support doesn't help if the platform itself is unfit for the purpose. It might be OK as a general purpose NTP server if you don't have any special requirements to accuracy, but for a PTPv2 grandmaster, having the ethernet behind a USB interface is a no-go. Regarding the RF interference - I'm running a Ublox M8T module directly mounted on the BBB via my custom GPSDO cape. It is working just fine. Disabling the onboard HDMI encoder might be the "secret sauce" for success. BR, Matthias === Matthias, my feeling is that if you want a precision source, neither BB not the RPi is a good solution. Maybe with all the tweak you mentioned the BB approaches precision (for some values of precision). I see the RPi as something which can provide far better NTP than simply using an Internet source, something which will be adequate for the majority of users (for some types of user!). The RPi 4 doesn't have E/net over USB hence my comment on seeing a comparison. The RF interference is to other parts of the spectrum - not specifically 1.5 GHz GPS - and has been documented. I noticed it on either 145 or 435 MHz bands when testing. [Jim] Whether anyone has bothered to do proper measurements I doubt. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Raspberry Pi NTP server
From: Matthias Welwarsky [] Forgive me chiming in with a recommendation: Drop the Raspberry Pi and get a Beaglebone Black instead. It is the much better platform for timekeeping experiments. Firstly, it has capture-mode timers that will give much more stable timestamps for the 1PPS kernel interface. Secondly, you can drive these timers from an external clock source. That clock source can be a GPSDO. That means, you can hook up the timer input clock to the 10MHz GPSDO output and at the same time use it for timestamping the GPSDO 1PPS pulses. Plus, this timer can be the "wall clock" for the Linux system, resulting in a zero-drift system time. Combine that with gpsd and you have a stratum-1 time source. Thirdly, the ethernet mac is on chip and it supports hardware timestamps. This means, not only NTP but also PTPv2 is possible. BR, Matthias === ... and it has much less general support ... and it generates more RF interference ... and it costs money as the OP already has the Raspberry Pi Neither make for "precision" sources. I've yet to see a comparison between the BeagleBone and a Raspberry Pi 4. I did make a comparison earlier which showed the BBB to be better, yes, but certainly not enough for me to change given the other factors. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Raspberry Pi NTP server
28 driver. I'd suggest the NTP Questions list, but it is /very/ fussy in what e-mail provider it accepts. Only one of my four works! https://lists.ntp.org/listinfo/questions Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] low power divide by 5
Here's a web page with several JK flip-flop dividers, including divide by 5: http://www.play-hookey.com/digital/counters/frequency_dividers.html Dave On 2020-06-30 15:47, dschuecker wrote: > Hi, > > a divide by five should possible with a synchronous state-machine made of 3 ( > sufficiently fast-) JK-FlipFlops. > > All 3 FFs are clocked with the input freq. , the outputs of the FFs are fed > back to the the JK-inputs, the divided freq. is output of one of the FFs. > > Additional constraints: no external ANDs or ORs or NOTs, the state-machine > does not get stuck in the 3 unused states. > > This turned out to be a very interesting problem and I do not yet come up > with a solution. Maybe there is none. Analytical solutions all failed, I will > try a brute force enumeration attack tomorrow. > > lots of fun ! > > Cheers > > Detlef > > Am 30.06.2020 um 08:37 schrieb Hal Murray: You might try the 74AC161, which > works to 73MHz at 3.3V or 103 MHz at 5V, -40 > to 85C. > Set the data inputs to DCBA = 1011 and connect an inverter from the carry > output (pin 15) to the Load input (pin 9) to divide by 5. See http:// > www.techlib.com/electronics/74161Divider.htm [1] You didn't read the data > sheet carefully enough. That 73 MHz is the bragging > number for sales people, often not useful. For something like this, you need > to add the clock-to-out for the ripple carry, prop time through inverter, and > setup time at the load input. > > I was going to ask whether 73MHz included the delay through the inverter, but > it's much worse than that. The clock to out on the RCO pin is 21 ns. Even > without the inverter, it won't make 50 MHz. > > You can save a few ns if you use a FF with inverting output instead of an > inverter. That adds a pipeline stage so you have to adjust the constant that > gets loaded. Setup time on a 3V AC74 is 4.3 ns which gets to 40 MHz (actually > only 39.5). > > At 5V, > AC161 clk-RCO is 15.2 > AC74 setup is 3.1 > So that works - 54.6 MHz. > > Using an inverter: > AC161 clk-RCO is 15.2 > AC04 prop 5.9 > AC161 setup 5.3 > That's 37.9 MHz > > (That's all assuming I didn't fatfinger anything.) > > I like Richard Karlquist's trick of using a data bit to reload. > Unfortunately, for the AC161, the data out isn't significantly faster than the > carry out. > > If I did the numbers correctly, that's 35 MHz at 3.3V and 49.3 MHz at 5V. ___ 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. Links: -- [1] http://www.techlib.com/electronics/74161Divider.htm ___ 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] Vibration isolation of quartz oscillators
Dr David Kirkby Ph.D C.Eng MIET Email: drkir...@kirkbymicrowave.co.uk Web: https://www.kirkbymicrowave.co.uk/ Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT. On Sun, 28 Jun 2020 at 12:44, Tom Van Baak wrote: > About slabs and stability... Around the world there must be a hundred > precision time labs, including official NMI (National Metrology > Institute) labs that contribute to the calculation of UTC itself. You > run into photos of these labs and their T gear on the web all the time > when you search for time nutty stuff. Those of us with home labs -- even > if just a few vintage frequency standards -- can relate. > > Anyone, one of my favorite lab photos is from VSL, the Dutch Metrology > Institute. Photo attached. [1] > > Spend time time pan/zooming around the gear in the photo. The usual > suspects: hp 105 quartz; TimeTech (I think); lots of SDI > (Spectradynamics); also Truetime or Symmetricom stuff; maybe that's an > old Tracor/Fluke VLF receiver on the far right (?); and of course lots > of Stanford Research SR620 counters, the TIC still used by almost every > time lab. > > But what really caught my eye was not just the four hp 5071A in the > foreground but *how they are mounted* -- on top of massive granite blocks! > There's a picture of a granite block here, at a former place I used to work as a student - EQD Aquila, the MODs calibration labs. https://www.derelictplaces.co.uk/main/military-sites/14101-aquila-mod-testing-facility-bromley-march-2004-a.html#.XvirQuco9PY about 60% of the way down the page. (Some of the pictures are quite amusing, as well as some of scientific interest). There's a couple of guys at my radio club used to work somewhere where a milling machine was turning high precision device. I just phoned one to ask what they used for anti-vibration, as I knew they took some precautions. He said they had dug a hole about 2 m into the ground, above that was 600 mm of "rubber", then 1.4 m of reinforced concrete. That used to stop lorries messing up the work. That's a different sort of application. I assume the OPs objects are quite large - not wrist watches. Otherwise, I was wondering if an active damping system might be practical. They certainly exist for laser tables https://www.newport.com/n/active-vibration-damping but I would imagine that for heavy 19" rack equipment, there would need to be quite a bit of power consumed in such a system. I've never done any calculations - just intuitively, I can't imagine that one could achieve anything useful without some pretty big power amplifiers. When I worked at UCL we had a laser table. Our department was near a main road. The laser table had gas-filled "dampers", but apparently these made the vibration problems worse rather than better, so the gas was removed. We never had any active system. Dave ___ 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] Elpromatime (Was Re: time-nuts Digest, Vol 191, Issue 28)
From: Dave B via time-nuts [] Also, has anyone tried this? (An alternative to Meinberg on Windows perhaps...) https://elpromatime.com/downloads/I'd take a look, but I don't run Windows here any more. Cheers n beers. Dave G8KBV Dave, It's the same version level as Meinberg (both one release out of date), and as Meinberg's compilation of the port works I don't see any reason to change. Make me wonder why they are bringing out their version. 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Stanford University online GPS course
On Sun, 21 Jun 2020 at 02:00, Alexander Sack wrote: > > This is indeed a fantastic course. The professor's explanation of the > pseudorange, the estimanda, and how to linearize them are absolutely must > see TV! > > I found his textbook a bit lacking though (there are better texts). > > -aps IIRC there are two profs and both had written text books on GPS. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkir...@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom ___ 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] Is there any way to recover if one messes up serial port on settings on HP GPS receivers?
On Wed, 17 Jun 2020 at 13:45, Tom Van Baak wrote: > Hi Dave, > There's not an easily accessible "reset to factory defaults" button > on the receiver like there is on many devices. > > Pull the AC or DC power cord. I'm curious why you ask. What state is > your 58503A that you have to resort to this? > > /tvb Thank you Tom. I had assumed that the serial port settings would be preserved in the event of a power failure. As I reported a week or two ago, Lady Heather will not communicate well with the receiver. I wondered if there was any point in trying a faster serial port speed. Lady Heather gets the time from the GPS receiver once, but then either 1) Windows reports the program is not responding. 2) The clock runs backwards. I thought it might be worth trying different serial port settings. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkir...@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom ___ 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] Is there any way to recover if one messes up serial port on settings on HP GPS receivers?
My HP 58503A is using the default 9600 8N1 for serial communication. It would be nice to run the connection faster, and there are commands to change the serial port speed, as well as reset the serial port settings to the defaults. What concerns me is that if I try to run the serial port faster, but have problems communicating with the receiver for whatever reason, then there will be no way to reset the receiver - I could not run the command to reset it. There's not an easily accessible "reset to factory defaults" button on the receiver like there is on many devices. It seems like one could get into a catch-22 situation, but perhaps there's a solution I am unaware of. Dave ___ 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] Lady Heather - sort satellites by dBc
From: Mark Sims You can sort a column either ascending or descending. Specifying which one to use with a click on the column header isn't easy or intuitive. Clicking anywhere on the sat info table zooms the screen to a detailed sat info screen = Thanks, Mark. Yes, I was thinking that having to code for a mouse hit on each column header would require more code than just a hit on the table. While it may be unusual in "text" programs, it's the standard in many graphics programs where a click sorts and a further click reverse the sort. It's something I've been asked for by users in my own software. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Lady Heather - sort satellites by dBc
The "GCS" command does that. BR, Matthias == Thanks, both. I'd looked at the help screen and not spotted it. I still think that a "standard" click on column header to sort would be more intuitive. Thanks to Mark for the program. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Lady Heather - sort satellites by dBc
In Lady Heather, it would be useful to sort satellites by dBc. I can't see a way to do this. Perhaps clicking on one of the table headings (e.g. dBc, PRN AZ EL etc.) could enable that column to be sorted? Thanks, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Free courses from the National Physical Laboratory (NPL)
NPL do a number of courses. Some are available online, some only in a class. The online ones can cost up to £700 (GBP). However, these are free until the end of June https://www.npl.co.uk/skills-learning/free-e-learning For anyone interested in metrology, there are a lot of relevant courses. Some are at quite an advanced level. For the vast majority of the courses there’s an exam at the end with a 50% passmark. I don’t think the certificates will of any use to me, but it added a challenge. I completed the “Introduction to Measurement and Metrology” course. I erroneously believed that the course was supposed to be 1-day, but there seemed to be a lot for a 1-day course. Later I realised it was supposed to be 0.5 days! I guess I am just a slow learner. The bit that took my largest amount of time to commit to memory was the roles of the BIPM, CGPM, CIPM, NMI, RMOs etc in disseminating the SI units. I must have watched the video on that ten times before I was confident I had a reasonably good understanding of that. The 40 minutes for the exam was more than enough time. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkir...@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom ___ 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] Alfred Loomis - an early time nut
You can watch the PBS American Experience program on him, "The Secret of Tuxedo Park" here: http://www.pbs.org/wgbh/americanexperience/films/secret-tuxedo-park/#part01 David N1HAC On 5/12/20 7:56 PM, Tom Van Baak wrote: Yes, the book about Loomis by Jennet Conant is highly recommended. The "time nut" pages are here: http://leapsecond.com/pages/loomis/Loomis-Tuxedo-Conant-p66-p70.pdf Besides being the man behind LORAN, and a hundred other clever ideas, he also pushed the state of the art in timekeeping, comparing the world's best pendulum clocks against the best quartz clocks: http://leapsecond.com/pend/pdf/1931-RAS-Analysis-Loomis-Chronograph-Brown-Brouwer.pdf http://leapsecond.com/pend/pdf/1931-RAS-Precise-Measurement-Time-Loomis.pdf http://leapsecond.com/pend/pdf/1932-Modern-Precision-Clocks-Loomis-Marrison.pdf See also: https://en.wikipedia.org/wiki/Alfred_Lee_Loomis "Alfred Lee Loomis (1887—1975) A Biographical Memoir by Luis W. Alvarez" http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/loomis-alfred.pdf "Tuxedo Park: A Wall Street Tycoon and the Secret Palace of Science That Changed the Course of World War II" https://physicstoday.scitation.org/doi/full/10.1063/1.1570779 "Talking with Alfred" https://scholar.harvard.edu/files/shapin/files/shapin_lrbtuxedopark.pdf "Alfred Lee Loomis - Obstetric ultrasound" http://www.ob-ultrasound.net/loomis.html "The scientist-tycoon whose work on radar helped win WWII" http://www1.lasalle.edu/~didio/reviews/rev_tuxedo_park.htm /tvb On 5/12/2020 4:24 PM, Bob Martin wrote: /Does anyone know about Alfred Loomis and his />/early precision time measurements? />//>/According to the article in the link below, he />/was also involved in WWII radar and the creation of Loran. />//>/http://www.ob-ultrasound.net/loomis.html />//>/bob/ ___ 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?
I use splitters made for satellite TV with good results, I think. They have response 5 MHz to >2 GHz and pass DC from any of the outputs to the input, so any or all GPS receivers can feed the antenna. Some cabling can be done with F connectors, or I add adapters as necessary (F to BNC adapters are common). I even have some amplified splitters, though I modify them so they pass the normally 5V from GPS RXs to antenna and have external 12V power for the amplifier. 73, David On 4/29/20 8:18 PM, Frank O'Donnell wrote: I'm looking for a splitter to allow three or four GPSDO's to share my roof-mounted Lucent PCTEL KS24019L112C 26db GPS twist antenna. I understand from scanning past threads that inexpensive splitters by companies like Mini-Circuits often turn up on eBay, but I'm having trouble narrowing down to one that will work for my situation. Can anyone recommend a specific splitter that wouldn't be too expensive? Thanks much, Frank ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C64250ece666c4b3893e408d7ec9e2961%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637238036359614332sdata=rxA7WPKnRwrt3AtIpFmgKGo8H6r%2BYysS4gJCSWC90S0%3Dreserved=0 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.
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 Frank, Yes! Passive splitters are /not/ what you want. Units like the one Bill mentioned have an amplifier built in, powered by one of the active GPS devices connected. I have two like this - one was GBP 70 as a private purchase (perhaps from someone on this list), the other was GBP 5 at an amateur radio rally in Glasgow. I suspect the owner of the GBP 5 one didn't realise its potential value. It's the one I'm using now and it works nicely. 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] MSF Annual Maintenance Shutdown
NPL has issued notice that ascheduled maintenance shutdown of the UK MSF service to allow safe working onthe masts and antennas will take place from 28 April - 13 May 2020. In previous years this hasnormally involved a daily off period between say 0800 and 1600 but this year'snotification just states. "The service will be off-air from 28 April - 13May 2020, but if the weather is unsuitable for work to be carried out, then theservice will not be turned off", which seems to imply a potential total shutdown over that period. Although there are no longer any out of service notifications for the Anthorn eLoran transmission I would expect that to be off for the same period. Nigel GM8PZR == The Web page also states: "In addition to these dates, the signal is likely to be taken off-air for a two-week period during summer each year, though the transmission will be restored overnight whenever possible. The dates of this longer outage will be announced on this page and by emailed notices to registered users as soon as they are known." so perhaps not a total shutdown, but it /may/ be on overnight. My cheap clocks seems to sync only overnight, so that may suit them. Actually we've been enjoying a spell of good weather the last couple of weeks, so an earlier period might have been ideally suited. https://www.npl.co.uk/msf-signal 73, David GM8ARV -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] NTP server using an OCXO, GPS chip and Raspberry Pi
From: Andreas Kempe Hello everyone, I want to build an affordable quality time source for my computer club. I've been toying with the idea of using an oven controlled oscillator from Ebay for getting a reasonable (0,5 ppm frequency stability) 1 PPS signal and a cheap GSP chip with UART for syncing the time. I was thinking of running this on a Raspberry Pi with FreeBSD and its gpiopps driver. Is this a reasonable setup for an affordable NTP server? Cordially, Andreas Kempe ___ Andreas, Here's an example of a simple device you can build: https://www.satsignal.eu/ntp/Raspberry-Pi-quickstart.html It's quite temperature sensitive, so either put it where the temperature is stable, or use ntpheat to keep the CPU at a much more constant temperature: http://www.satsignal.eu/ntp/Raspberry-Pi-ntpheat.html With those recommendations, and noting the delays in RPi I/O (at least in the earlier RPi cards where Ethernet is over USB), I would suggest that an OCXO is overkill. No reason to deviate from the Raspbian OS. You can gauge the performance from various Raspberry Pi devices here: http://www.satsignal.eu/mrtg/performance_ntp.php Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] On choosing reasonable synthesizer PN requirements
Hi The “wiggles” he is chasing are about 2-3 Hz (by eyeball on his charts). At 2.4 GHz, that is a fairly convenient ~1 ppb. The Z-3801 (if it was in good health) should be easily able to hold that level of performance. It’s not clear which MD-011 he is using, but it is a pretty good bet it will also hold that level as well. The usual disclaimers about good satellite view for the GPSDO’s would of course apply. Substituting a typical telecom Rb for either device would likely also allow the wiggles to be observed (or not). That would take out the whole dependence on GPS. (Yes I realize those comments are probably better directed to those involved ….). Bob If you follow his Twitter feed: https://twitter.com/ea4gpz I think it's all but certain that it's the local oscillator in the satellite-borne transponder is the cause of the problem. He's looked at an engineering beacon on the satellite too. The orbital calculations involved need to be quite accurate. I thought it might interest those chasing the ultimate precision! Probably ought to change the title of this topic, but I'm unsure of the protocol here about so doing. Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] On choosing reasonable synthesizer PN requirements
From: Karen Tadevosyan via time-nuts Hi, one of the interesting HAM radio topic in Europe now is the use of the new geostationary satellite Phase-4A (QO-100) for analog and digital modes via a 2.4/10 GHz transponder. [] === ... and Time-Nuts may be interested in some oscillator measurements made by Daniel Estévez showing some unexpected steps. His blog is here: https://destevez.net/2020/04/wiggles-in-the-qo-100-local-oscillator/ It's a fascinating story, and may not yet be complete. Daniel is a GNSS Engineer by occupation. Cheers, David GM8ARV -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] OCXO and fluctuations after EFC adjustment
Well, that's how it's supposed to be done, but these days the usual (and often only) criterion other than part value (e.g. 15V 200uF +/- 10%) seems to be cost (cheapest == best). Sad isn't it. David -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob kb8tq Sent: 11 April 2020 14:05 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OCXO and fluctuations after EFC adjustment Hi Bottom line is that, as long as one is careful about *which* vendors supply which parts, normal parts do the job. Nobody is going to publish that selection process or the results. They very much want the “other guy” to have to do it on their own. The 78L12 might look just like one from 5 other vendors. It also might work 10X better than the others. Those caps may look pretty normal. They came from “this guy” and not “those guys”. That cheap looking thermistor might have spent a few years in evaluation before it was approved for use. There is a lot of work that goes into component selection. It simply does not result in $20 bulk metal film parts with 0.2 ppm/ C specs getting used. It is a lot more difficult to spot in the finished product. Bob > On Apr 11, 2020, at 3:15 AM, John Moran, Scawby Design > wrote: > > On Fri, 10 April 2020 14:31:53 -0700 Rick wrote: > > >> At this time, I will give my usual speech about IMHO the fact that > >> since the invention of the DDS on a chip, EFC should no longer be used > >> for high performance oscillators. > > During my 50 years in the electronics industry I have always been puzzled > about one aspect of crystal oscillators. They go to great lengths to use a > precise piece of quartz as the heart, because of its unique properties, and > then add standard external components - capacitors, varactors, Zeners, etc. > to tweak its frequency. All these components vary far more than the original > piece of quartz ... hence my confusion. > > I know it is practically impossible to grind a crystal to exactly the > frequency you want, and it then drifts over time, but what is the logic of > using relatively wildly varying components to adjust the quartz? Are their > temperature and ageing characteristics swamped by the superior crystal? > > In all the papers I have ever read, the subject is never mentioned ... you > just add a variable capacitor and/or an EFC circuit and job done. > > I guess this is showing my total ignorance here, but I would like to know. > > Maybe this is at the heart of Rick's usual speech? > > 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. ___ 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.
Re: [time-nuts] Phase noise confusion II
IIRC the latter -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Dana Whitlow Sent: 10 April 2020 11:06 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Phase noise confusion II Question about definition of jitter: Is it the variation in pulse-to-pulse spacing, or is it the variation in pulse positions with respect to a jitter-free waveform? Dana ___ 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] Buffer amplifier, OP Amp, vs MMIC, vs discrete?
If you look at the way the power is supplied to and output is taken from an MMIC there's no way that I can see that they could go all the way to DC as there's always a capacitor in the output ... I got all excited a while back when I considered an MMIC for a project because the spec said DC-xGHz. Sadly the specified circuit for using it meant there's no way it could get the DC, though a large output capacitor in parallel with a RF cap would allow audio to GHz. Hmmm where did I leave the 1 MegaFarad capacitor. D. -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Taka Kamiya via time-nuts Sent: 03 April 2020 23:07 To: Discussion of Precise Time and Frequency Measurement Cc: Taka Kamiya Subject: [time-nuts] Buffer amplifier, OP Amp, vs MMIC, vs discrete? > But I have never seen a suggestion of MMIC like ones from Mini-circuits. > There are few that work from DC, fairly good NF, but often too high of gain. > Other than high gain, are there reason NOT to use MMIC? --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG ___ 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.
Re: [time-nuts] HP3588A battery
The service manual says it is a manufacturer's part number T06/46 which is a Saft number and a Google search shows a number of equivalents, including the Tadiran. David N1HAC On 3/29/20 5:35 PM, Charles Steinmetz wrote: Matthew wrote: It looks like I need to replace the battery in my HP3588A spectrum analyzer. The service manual says the HP part number is 1420-0336. I would like to obtain a replacement battery & be ready to swap out the old battery for a new one. Anyone out there know what might be a decent replacement battery? The 3588A battery is a Tadiran TL-5903/P 3.6v Lithium Thionyl Chloride cell, available from multiple vendors. Allied has them for $8.14 each in single quantities. I put together a document that covers the replacement procedure, which I will send you by PM. Best regards, Charles ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C5f8fadaeeeab450d818408d7d42c2ba3%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637211158487652995sdata=CIUF3H8HuxTLcoP4vb5G17y6BkQHIaBgIz9LJf3vpGY%3Dreserved=0 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.
Re: [time-nuts] weird Raspberry PPS+GPS NTP server behaviour
Folks, Thanks for all the help. I've put up a simple Web page showing the program and its results here: https://www.satsignal.eu/ntp/Raspberry-Pi-ntpheat.html A good gain on that Raspberry Pi in a centrally heated room and nearer the radiator than it should be. Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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 5335A counter and GPIB control
Don't buy the 82357B - hardware is fine but the Keysight IO Libraries software is totally dreadful. See recent posts by myself on hp-agilent-keysight-equipm...@groups.io and EEVBlog David -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Perry Sandeen via time-nuts Sent: 12 March 2020 22:13 To: time-nuts@lists.febo.com Cc: Perry Sandeen Subject: [time-nuts] HP 5335A counter and GPIB control Learned Gentlemen, I D/L'd the John Miles' toolkit. It's just what I was looking for! Another question. There are numerous GPIB-USB adapters available on ebay most go for $75 and up. Yet ther is this company UGPlus USB to GPIB controller Made in USA that sells their units for $46 shipped. Does anyone know how well they work or if they need more software or *fiddling around* than the more expensive units? 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. ___ 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] Trueposition behavior
I think it would be a dead-band. David N1HAC On 3/10/20 2:41 PM, djl wrote: Is this effectively dither on the control voltage? On 2020-03-10 10:30, Skip Withrow wrote: Hello Time-Nuts, A couple of weeks ago I posted regarding some weird behavior of the Trueposition GPSDO that I was seeing. I have now been able to get back to the problem and have further results to report. I have several of these GPSDOs that are version 12.0.1 (I believe the latest is 12.1.1) and they all seem to behave the same. I have attached two Lady Heather plots. One is the GPSDO output of the control voltage, the other is the 10MHz output monitored by another NTBW GPSDO. The bumps in the control voltage are what was bothering me. It appears that the way this GPSDO operates is to let the oscillator free run until there is 50ns of accumulated time error (LH reports 'Normal' during this phase), Then it goes into control mode, you can see more noise on the DAC signal during this time plus the big spike, and yanks the phase back to zero (LH reports 'Acquiring' during this phase). The unit must model the OCXO drift as the DAC does change during the drift period. So, the longer the unit runs the longer between upsets (hopefully). These plots were taken shortly after start up, I am in the process of letting it run for a while now. BTW, the very periodic dropping and acquisition of the WAAS bird (PRN138) is still present. This behavior is a good news/bad news situation. On one hand, during the drift period the output of the GPSDO is not influenced by GPS and getting yanked around second by second (like the Thunderbolt). On the other hand, if the 50ns yank happens when you are making a measurement it kind of trashes things. I haven't tried seeing if LH can disable disciplining (for use during measurement periods). Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cbb722bbdb01b4db9fe0308d7c522c000%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637194625354501923sdata=Bx2snhE2Wbc0Fo7MNo9kcsQ61JNeycC%2FEt90tEA657k%3Dreserved=0 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.
Re: [time-nuts] Yukon to make Daylight Saving Time permanent after final time change Sunday
I still maintain that if people want another hour in the evening, they can get up an hour earlier. Why do they think they need to change the clocks? Some people just can't deal with reality and need someone else to make their decisions for them. OK, I will step off my soapbox now. :-) David N1HAC On 3/6/20 1:41 PM, Peter Loron wrote: This is really shouldn’t be an issue. Many car manufacturers are leveraging and improving already existing cellular data systems in their cars to provide software and firmware updates over the air. I suspect the issue is more the long supply chain lead times…there is a several year lag between deciding to have a feature and getting the car hardware and software out to the public. Unless you are Tesla. -Pete On Mar 6, 2020, at 07:10, GERRY ASHTON wrote: I just got a 2020 car which offers to sync the clock on the instrument panel to the GPS receiver. But the time zone and observance of DST must be set manually. In principle, if the position is known, the time zone and DST can be looked up. But since the software in the car is not routinely updated and the various national, state, and provincial legislatures like to monkey with this, look up is not feasible. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cb5c3ff5971844896197108d7c1fe05b0%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637191169071271398sdata=SB%2Fh3Jl%2FDSrKykbyjKNMCyuSQSKUbyjWIm3yszWTP5s%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cb5c3ff5971844896197108d7c1fe05b0%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637191169071271398sdata=SB%2Fh3Jl%2FDSrKykbyjKNMCyuSQSKUbyjWIm3yszWTP5s%3Dreserved=0 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.
Re: [time-nuts] Yukon to make Daylight Saving Time permanent after final time change Sunday
GMT EVERYWHERE!! -- 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 ___ 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] weird Raspberry PPS+GPS NTP server behaviour
From: folkert You can also keep the GPU busy. That'll work as well with the bonus that the main cpu stays mostly idle (iirc) for other tasks. https://vanheusden.com/ntpheat.cpp requires https://github.com/mn416/QPULib === That's neat! Thanks! Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] weird Raspberry PPS+GPS NTP server behaviour
The source code is here: https://github.com/ntpsec/ntpsec/blob/master/contrib/ntpheat It imports ntp.util. But from my rudimentary knowledge of Python I see that it only uses it to get version number. So I think removing lines 24-29 and 51-53 should make it work without ntpsec. Cheers, Adam = Thanks, Adam and Hal. I will have a play. I need to decide which of my flock to use, as some already sit in a fairly stable environment, and others are doing real work which may be affected by running the CPU at 100%. OK, there's a non-critical one rather nearer to a CH radiator than I would like, so I've started it there (no error messages after the edits you suggested). I ran it as background and logged out. I guess it doesn't need any privilege. https://www.satsignal.eu/mrtg/performance_raspi-12.php Thanks for drawing my attention to this. Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] weird Raspberry PPS+GPS NTP server behaviour
It's ~65°C on purpose. I'm using ntpheat ( https://blog.ntpsec.org/2017/02/01/heat-it-up.html) to keep stable temperature no matter what it does. It turns my raspberry into kind of OCXO :) Anyway, ntpheat runs there for months, so I guess it's not the culprit. Cheers, Adam Agreed, if it was running before then it's not the culprit this time. I didn't know about that program and I'd like to try it here. A neat idea. Is it available stand-alone - ready to run? I could compile it here given the source, but not if it has dozens of dependencies on NTPsec, which I don't use. Temperature is certainly the prime contributor to instability here (or temperature variations produced by CPU load variations). Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] weird Raspberry PPS+GPS NTP server behaviour
Hi! For several weeks I'm seeing strange behavior of my Raspberry Pi based NTP server with Uputronics GPS PPS expansion board (Ublox MAX-M8Q chip). Several weeks ago the mean daily jitter was below 300 ns, offset didn't exceed ±1 µs, provided no restart or configuration change was made. Now the offset often wanders even below 5 µs, steady change, and then comes back. You can see it at the screenshot from my Grafana server (attached). As you can see, the number of satellites visible and TDOP value should not be the cause of it. My current ntp.conf is as follows (I use ntpsec and gpsd): driftfile /var/lib/ntp/ntp.drift leapfile /var/lib/ntp/leap-seconds.list statsdir /var/log/ntpstats/ statistics loopstats peerstats filegen loopstats file loopstats type day enable filegen peerstats file peerstats type day enable restrict default limited kod nomodify nopeer noquery restrict source nomodify noquery restrict 127.0.0.1 restrict 192.168.0.0 mask 255.255.0.0 tos mindist 0.002 refclock shm unit 1 minpoll 4 maxpoll 4 flag4 1 prefer refid PPS refclock shm unit 0 minpoll 4 maxpoll 4 time1 0.057984 refid GPS #server nts.time.nl nts #server nts.ntp.se:4443 nts server tempus1.gum.gov.pl prefer server tempus2.gum.gov.pl server ntp.task.gda.pl server ntp.nask.pl server MY_GPSDO iburst Before that I thought it was because I used NTP pool, as some time ago similar behavior was mentioned here on the list, but, as you can see, I do not use it anymore and the same strange behavior remained. Any idea what could be the cause of this? Thanks in advance. Adam What are you doing to that poor RPi to drive its CPU up to 66 C! Rather hot! That's the first thing I would investigate if the CPU load is really so low (9%). Comparing, my oldest RPi server is a lowly RasPi 1B, and it runs at 2% CPU, ~43 C CPU (averaged over a day). It lives in an unheated cupboard on an outside wall. Cheers, David -- SatSignal Software - Quality software for you Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ 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] Are there SC-crystals out there in the wild that are not Overtone?
I remember opening up those military crystals and sanding them down with Ajax cleaner to raise the frequency or rubbing a little solder on the plate to lower it for CW transmitters. High school days. -- 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 ___ 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] Fake new LPRO 101 Rb's on Ebay?
Re: China, I heard a piece on NPR that gave the opinion that the virus would only survive a few hours on a surface. Anything coming from China should be fine. We are probably more likely to die from panic. ;-) David N1HAC On 2/4/20 4:54 AM, Clint Jay wrote: Actinic short wavelength UV light, the same stuff you use to erase EPROMs or sterilise scissors, pond or aquarium water will do the job but, a little perspective, there are 1.386 billion people in China and fewer than 21,000 confirmed cases of coronavirus, fewer than 500 deaths since the outbreak began, thus far more people have died from seasonal flu today alone. I leave the reader ( who will probably be far better with statistical analysis than I) to calculate the chances of a person infected with the virus coming into contact with a package, then you can work out the chances of said virus surviving the time the journey takes. I'm not going to bother sterilizing goods from China and won't be panicking, instead I'll wash my hands and cough/sneeze into tissues. The Chinese LPro look like a good deal but the Israeli ones have the connector and a module which seems to break it out to a d-sub and SMA, might make it worth the extra? On Tue, 4 Feb 2020, 09:35 Christoph Kopetzky, wrote: Ah OK, now I found the other offers... OK China... Sorry for my quick first answer. I agree with Esa. Ozone is a good method for contact-free desinfecting goods. The other alternative will be UV light. But ozone is much better. best regards Chris --- 'Everything should be made as simple as possible, but not simpler.' -- Albert Einstein Am 04.02.2020 um 10:03 schrieb Christoph Kopetzky: The seller is located in Israel :) not in China. So the corona would not really be the problem. But the items are not new(!). The product date code is 06/21/00 for the one and 0127 as 27th week of 2001 is for the second one. best regards Chris --- 'Everything should be made as simple as possible, but not simpler.' -- Albert Einstein Am 04.02.2020 um 08:29 schrieb Perry Sandeen via time-nuts: Yo Bubba Dudes!, There are two vendors on Ebay selling *new* LPRO 101 Rb's for around $160 each, with discounts for larger purchases. The general price of a used LPRO seems to be in the $250 to $350 range. Anybody have any ideas? (Discount for coronavirus?) In all seriousness, can the coronavirus be transmitted in gear we buy from China or does it require a living host for spreading? Regards, Perrier ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cd47e2df5838343547eae08d7a95851d1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637164069114169750sdata=iKNVvxnImkVoo%2FQgysqx1%2BC3sc1BuM65ltwKygilT14%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cd47e2df5838343547eae08d7a95851d1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637164069114169750sdata=iKNVvxnImkVoo%2FQgysqx1%2BC3sc1BuM65ltwKygilT14%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cd47e2df5838343547eae08d7a95851d1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637164069114169750sdata=iKNVvxnImkVoo%2FQgysqx1%2BC3sc1BuM65ltwKygilT14%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cd47e2df5838343547eae08d7a95851d1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637164069114169750sdata=iKNVvxnImkVoo%2FQgysqx1%2BC3sc1BuM65ltwKygilT14%3Dreserved=0 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.
