[time-nuts] Re: Oncore UT+ EEPROM -
k1...@att.net writes: > I have an Oncore UT+ for a project and found that it works fine after > updating the almanac and getting a 3D fix but it never stores my location > coordinates in its EEPROM. Each time I power up it shows all zeroes in Lat, > Lon, Alt for about an hour or so until it finds satellites. With Lady > Heather I tried entering my coordinates and this leads to faster tracking. > Is this normal Oncore UT+ behavior? Any advice other than a battery backup. As far as I know, the EEPROM (Flash?) is only used for code. The almanac and other changing info is in battery-backed NOVRAM. -- 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] Oncore UT+ EEPROM -
I have an Oncore UT+ for a project and found that it works fine after updating the almanac and getting a 3D fix but it never stores my location coordinates in its EEPROM. Each time I power up it shows all zeroes in Lat, Lon, Alt for about an hour or so until it finds satellites. With Lady Heather I tried entering my coordinates and this leads to faster tracking. Is this normal Oncore UT+ behavior? Any advice other than a battery backup. Jerry NY2KW -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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: Seeking advice: Is this the right way to check very short term (below 1s) stability?
Erik, Den 2021-11-28 kl. 19:19, skrev Erik Kaashoek: As the collection of frequency sources and counters in my home lab is growing I'd like to understand the performance of the frequency sources. Two different GPSDO do help to check long term stability. But the Rubidium frequency standard I have (Accubeat AR60A) is fairly unknown and seemingly not of good reputation, more specifically its (very) short term stability is doubted. So how best to check very short term (below 1s) frequency stability. The frequency counters available loose resolution quickly when the gate time is reduced below 1 second and high performance phase noise measurement equipment is not available so google helped with a search for alternative measurement methods. What I found was a method using two frequency sources, one of the two being a VCO, a mixer and some filters and amplifiers. By weak locking (large time constant) the VCO source using the mixer as phase detector to the other source, the output of the mixer's IF port should carry a voltage real time proportionally to the phase difference and by filtering and amplifying it should be possible to check for variations in the 1ms-1s range. Maybe even a scope can see the variations. When you know the amplification and the full range voltage you can even do an absolute measurement. Would this method work? Any specific concerns to take note of when doing the measurement? Removing the DC component (or locking the VCO such that there is no DC component) will be crucial I guess but given the slow speed of the loop even an ADC->computer->DAC->VCO setup can work. Any suggestion is welcome. So, in that region one typically transition into measuring phase noise, as for shorter taus your performance will be dominated by the wideband white noise, and counters isn't the best tool to analyze that. The weak locking technique can be used to a limit, but to get good results, you need to calibrate it. I suggest you set up the loop in the analog domain and only digitize the residual noise. Then inject using a synthesizer side-tones to your carrier and know relationship in amplitude and frequency offsets, for which then the phase-noise should be known, and use that to build a calibration scale. This is described in the NIST T&F catalog. You can do that with a varity of sources, but eventually you will be limited by the noise of the other oscillator. I use a cross-correlator setup in the form of TimePod most of the times, with quiet references. Cheers, Magnus ___ 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: Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input
For those interested, Dave PA5DOF and your's truly are working to get the doubler implemented that Luciano has on his website. The first PCB prototype is in and has been built and works OK. Some minor tweaks/fixes will be added to a V0.2 PCB. If there is interest I can share the Gerber files. The doubler is intended to be hooked up to an Efratom MRK-HLN 5MHz Rb. Our shack T&M equipment for the best part requires a 10MHz reference. Wilko > On 29 Nov 2021, at 10:35, tim...@timeok.it wrote: > > > you can use this: > > > http://www.timeok.it/wp-content/uploads/2015/08/high-performance-frequency-doublerv1-31.pdf > > Luciano P. S. Paramithiotti > tim...@timeok.it > www.timeok.it > > Da "Matt Huszagh" huszaghm...@gmail.com > A time-nuts@lists.febo.com > Cc > Data Sun, 28 Nov 2021 19:29:58 -0800 > Oggetto [time-nuts] Lowest noise (phase noise and ADEV) method to achieve > 10 MHz signal from 5 MHz input > Hi, > > I've got a 10 MHz distribution amplifier and am considering purchasing a > 5 MHz reference. Most (not all) of my equipment accepts a 5 MHz > reference, but I'd like to be able to use the existing distribution > amplifier I have if possible. Therefore, I'm considering ways I might > generate a low-noise 10 MHz signal from the 5 MHz reference. > > An obvious way is to use a doubler. However, as I understand it, even an > ideal doubler will add 20log(2)=6 dB of phase noise to the 10 MHz > signal. It seems like a possibly more expensive, but lower noise way > would be to use a PLL with a divider that locks the divided 10 MHz > signal to the 5 MHz input. If the time constant of the loop filter is > set long enough, does this avoid the phase noise multiplication issue? > From what I've gathered, this is a technique HP used in some of their > gear. For example, the 8566 and 8340/1 lock a 100 MHz VCXO to an > external reference with a PLL. > > Any other thoughts on this? > Matt > ___ > 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: Project Great
Hi All these devices *can* be sensitive to the environment. What degree of sensitivity they have is a function of how “nutty” one went on this or that design. It also is a function of things like cost, size, and power consumption. The target market for things like the 5071 is a “we can afford it” sort of crew. Even today various government agencies from various countries buy the bulk of the 5071’s produced. Yes sorting this out is a bit complicated. Multi step procurement is pretty common. Telecom Rb’s and OCXO’s normally go into a *very* different market. There is indeed a “good enough” point at which the willingness to pay goes away. Temperature stability is one of many things that could be better if more money / power / volume was thrown at the problem. So no, not a simple single answer. Bob > On Nov 29, 2021, at 9:55 AM, Lux, Jim wrote: > > On 11/29/21 1:57 AM, Hal Murray wrote: >> j...@luxfamily.com said: >>> And a lot ofsources may have a low flat spot in the curve, but it >>> eventually trends up. Except for primary standards like Cs beam. >> What's magic about "primary standard" or "Cs beam" that keeps the ADEV from >> trending up? >> > Their ultimate accuracy is dependent only on a invariant physical property > that is independent of time. > > A quartz crystal ages. No matter how good your oven is, the frequency will > change over a long time. > > Mercury ions, Cs ions (perhaps all ions?) have frequencies that are a > fundamental property of the ion. There might be practical implementation > limits or side effects that limit the lowest achievable uncertainty - hot > atoms will have higher variance than cold atoms, for instance. So not all Cs > primary standards have the same ultimate performance. > > > ___ > 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: Project Great
On 11/29/21 1:57 AM, Hal Murray wrote: j...@luxfamily.com said: And a lot ofsources may have a low flat spot in the curve, but it eventually trends up. Except for primary standards like Cs beam. What's magic about "primary standard" or "Cs beam" that keeps the ADEV from trending up? Their ultimate accuracy is dependent only on a invariant physical property that is independent of time. A quartz crystal ages. No matter how good your oven is, the frequency will change over a long time. Mercury ions, Cs ions (perhaps all ions?) have frequencies that are a fundamental property of the ion. There might be practical implementation limits or side effects that limit the lowest achievable uncertainty - hot atoms will have higher variance than cold atoms, for instance. So not all Cs primary standards have the same ultimate performance. ___ 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: Project Great
Hi, Den 2021-11-29 kl. 10:57, skrev Hal Murray: j...@luxfamily.com said: And a lot ofsources may have a low flat spot in the curve, but it eventually trends up. Except for primary standards like Cs beam. What's magic about "primary standard" or "Cs beam" that keeps the ADEV from trending up? "primary standard" is an overloaded term, so depending on context a particular product may suffice to be a "primary standard" in some context but not in others. In general a "primary standard" does not need external corrections, and some clocks will have less than perfect mechanisms for their systematic variations or drift, which does not covers the ADEV, as ADEV is not covering systematic properties but is only intended to cover random noise. For metrology contexts, "primary standards" is only a handful of cesium foutains to achieve frequency accuracy, where as the bulk of atomics clocks contribute stability (i.e. optimal ADEV). In telecom, a "Primary Reference Clock (PRC)" or "Primary Reference Source (PRS)" ensures frequency within +/- 1E-11, which used to be what analog cesiums could achieve. Requirements have since progressed, especially for the phase as time is now an added. So, in general, it's about the repetitive independent generation of phase, frequency and drift. Stability in terms of ADEV and TDEV then comes in as othogonal requirement. I think you will find that IEEE Std 1139 and 1193 has further refinements as they pop out of the approval and publishing. 1139 draft is now in balloting process. We still work on 1193. I also recommend having a look at VIM and GUM documents as available from BIPM. Cheers, Magnus ___ 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: Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input
Hi The PLL will have the same 20 log N issue plus a number of other problems. The big question is: what are you after? If you need something below -175 dbc / Hz far removed, what is the application? There may well be better ways to do this or that. If you are after -125 dbc / Hz at 1 Hz, that’s a very different need and the approach to getting it would be significantly different. Simple answer is that most equipment is not all that sensitive to phase noise and that distribution amps have a noise floor. You can go nuts getting a super quiet reference and it will have no real impact outside a few very specific applications. ( which likely will need custom “plumbing”). Bob > On Nov 28, 2021, at 10:29 PM, Matt Huszagh wrote: > > Hi, > > I've got a 10 MHz distribution amplifier and am considering purchasing a > 5 MHz reference. Most (not all) of my equipment accepts a 5 MHz > reference, but I'd like to be able to use the existing distribution > amplifier I have if possible. Therefore, I'm considering ways I might > generate a low-noise 10 MHz signal from the 5 MHz reference. > > An obvious way is to use a doubler. However, as I understand it, even an > ideal doubler will add 20log(2)=6 dB of phase noise to the 10 MHz > signal. It seems like a possibly more expensive, but lower noise way > would be to use a PLL with a divider that locks the divided 10 MHz > signal to the 5 MHz input. If the time constant of the loop filter is > set long enough, does this avoid the phase noise multiplication issue? > From what I've gathered, this is a technique HP used in some of their > gear. For example, the 8566 and 8340/1 lock a 100 MHz VCXO to an > external reference with a PLL. > > Any other thoughts on this? > Matt > ___ > 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: HP 5065A on ebay
Poul-Henning Always fun to take a look and some very attractive starting bids. But then as time goes by it will get crazy as always. Then $400 or so in shipping and heavens knows what customes will be. Oh well nice to look. Thanks Paul On Mon, Nov 29, 2021 at 3:28 AM Poul-Henning Kamp wrote: > > ew via time-nuts writes: > > And there's a 5071A "for parts only" too if anybody feels like an > adventure: > > > https://www.ebay.com/itm/154720557764?hash=item2406105ac4:g:e~8AAOSwTP5hoOG3 > > -- > 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: Project Great
Hal Murray writes: > > j...@luxfamily.com said: > > And a lot ofsources may have a low flat spot in the curve, but it > > eventually trends up. Except for primary standards like Cs beam. > > What's magic about "primary standard" or "Cs beam" that keeps the ADEV from > trending up? Primarily (no pun intended) that there are no (relevant) mechanisms of frequency drift. Cesium beam standards measure free-flying atoms which means the only relevant external influence is the black-body radiation, which is constant, thanks to the thermostatic ovens. Rubidium standards measure atoms which are confined in a glass-bulb, which means they literally bounce of the walls all the time. The resonance we measure is not the real one, but one affected by the doppler-shift of the atoms speed, ie: velocity without sign, in the direction of interrogation. This also broadens the resonance. I belive the primary source of drift in Rb's are adsorption and absorption of Rb molecules onto and into the glass itself. This causes a drop of gas pressure, which changes the collision dynamics for the remaining Rb gas, which affects their velocity distribution, which again moves the "appearant resonance" we measure. One of the things which set the 5065A apart from "telecom" Rb's is that there is a side-reservoir which is cooled with a TEC to stabilize the gas pressure and thus velocity. If you put your Rb atoms in a fountain instead, they work as well, or even slightly better than Cs atoms. -- 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: Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input
I see you are using two for the phase noise test setup (a common way of doing it). I am curious about the phase matching between units. From the results it appears they must be pretty well matched, but did not see any actual data. Since it is over a very narrow frequency BW it should be no problem. Thanks & Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 848-245-9115 -Original Message- From: tim...@timeok.it Sent: Monday, November 29, 2021 4:35 AM To: time-nuts@lists.febo.com Subject: [time-nuts] Re: Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input you can use this: http://www.timeok.it/wp-content/uploads/2015/08/high-performance-frequency-d oublerv1-31.pdf Luciano P. S. Paramithiotti tim...@timeok.it www.timeok.it Da "Matt Huszagh" huszaghm...@gmail.com A time-nuts@lists.febo.com Cc Data Sun, 28 Nov 2021 19:29:58 -0800 Oggetto [time-nuts] Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input Hi, I've got a 10 MHz distribution amplifier and am considering purchasing a 5 MHz reference. Most (not all) of my equipment accepts a 5 MHz reference, but I'd like to be able to use the existing distribution amplifier I have if possible. Therefore, I'm considering ways I might generate a low-noise 10 MHz signal from the 5 MHz reference. An obvious way is to use a doubler. However, as I understand it, even an ideal doubler will add 20log(2)=6 dB of phase noise to the 10 MHz signal. It seems like a possibly more expensive, but lower noise way would be to use a PLL with a divider that locks the divided 10 MHz signal to the 5 MHz input. If the time constant of the loop filter is set long enough, does this avoid the phase noise multiplication issue? From what I've gathered, this is a technique HP used in some of their gear. For example, the 8566 and 8340/1 lock a 100 MHz VCXO to an external reference with a PLL. Any other thoughts on this? Matt ___ 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: Project Great
j...@luxfamily.com said: > And a lot ofsources may have a low flat spot in the curve, but it > eventually trends up. Except for primary standards like Cs beam. What's magic about "primary standard" or "Cs beam" that keeps the ADEV from trending up? -- These are my opinions. I hate spam. ___ 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: Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input
you can use this: http://www.timeok.it/wp-content/uploads/2015/08/high-performance-frequency-doublerv1-31.pdf Luciano P. S. Paramithiotti tim...@timeok.it www.timeok.it Da "Matt Huszagh" huszaghm...@gmail.com A time-nuts@lists.febo.com Cc Data Sun, 28 Nov 2021 19:29:58 -0800 Oggetto [time-nuts] Lowest noise (phase noise and ADEV) method to achieve 10 MHz signal from 5 MHz input Hi, I've got a 10 MHz distribution amplifier and am considering purchasing a 5 MHz reference. Most (not all) of my equipment accepts a 5 MHz reference, but I'd like to be able to use the existing distribution amplifier I have if possible. Therefore, I'm considering ways I might generate a low-noise 10 MHz signal from the 5 MHz reference. An obvious way is to use a doubler. However, as I understand it, even an ideal doubler will add 20log(2)=6 dB of phase noise to the 10 MHz signal. It seems like a possibly more expensive, but lower noise way would be to use a PLL with a divider that locks the divided 10 MHz signal to the 5 MHz input. If the time constant of the loop filter is set long enough, does this avoid the phase noise multiplication issue? From what I've gathered, this is a technique HP used in some of their gear. For example, the 8566 and 8340/1 lock a 100 MHz VCXO to an external reference with a PLL. Any other thoughts on this? Matt ___ 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: HP 5065A on ebay
ew via time-nuts writes: And there's a 5071A "for parts only" too if anybody feels like an adventure: https://www.ebay.com/itm/154720557764?hash=item2406105ac4:g:e~8AAOSwTP5hoOG3 -- 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.
