Re: [time-nuts] DIY VNA design

Hi One option in the "1 GHz and down" range is to team up a surplus HP S-Parameter test set with your own electronics. That way you let HP do all of the fancy directional coupler stuff and relays. They don't sell well on the auction sites. The result is that a bit of time making lowball offers

Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

Hi Ok let's toss some numbers into the mix. The counter time base one day after calibration is in the 0.5 to 1.5 ppb range. The LPRO ten years after it left the factory is in the 0.5 to 1.5 ppb range. The GPSDO when running properly should be in the 0.005 to 0.02 ppb range at one second. One

Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

Hi I do not know of any commercial GPSDO's that do not have a holdover feature. There are a lot of variables. With a large package OCXO and a couple days operation, the numbers I gave should be good 90 to 99% of the time.(99 seconds out of 100). If the unit has such a poor antenna location

Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

Hi If your time base is doing < 5 ppb per year, that is an unusual 10811. I suspect it does not spend a lot of time powered off. Bob Sent from my iPad > On Aug 19, 2016, at 10:10 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> Ok let's toss some numbers into the

Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

Hi At the most basic level, ADEV is a standard deviation. When people read an instrument they usually want a "max error" sort of number. ADEV operates on delta between readings so a simple "three sigma" mental math conversion is not all you need. It *is* the right measure. It can take a bit of

Re: [time-nuts] DIY VNA design

Hi If you really want to work out the delays through all of this GPS "stuff" ahead of the RF -> PPS conversion, a VNA is about the only good way to do it. Bob > On Aug 21, 2016, at 6:59 PM, Dr. David Kirkby (Kirkby Microwave Ltd) > wrote: > >> On 21 Aug 2016

Re: [time-nuts] GPSDO - probably a stupid question.

Hi You can update the EFC a billion times a second. Update rate and bandwidth are not the same thing. If you want good ADEV, the loop better not have a bandwidth greater than 0.01 Hz. GPS ADEV is pretty awful at 1 and 10 seconds. It is starts to be good past a few thousand seconds. Yes, older

Re: [time-nuts] Optical link connects atomic clocks over 1400 km of fibre

Hi I would not rule out line noise into the electronic side of things. Bob > On Aug 23, 2016, at 7:06 PM, Magnus Danielson > wrote: > > Don't over-interpret the 50 Hz aspect, I don't remember those details from > 4.5 months back or so, as I already indicated. I

Re: [time-nuts] Optical link connects atomic clocks over 1400 km of fibre

Hi There is also the minor issue of putting the (very thick) layers on in a spiral around the "core". You put one layer on clockwise and the next counter clockwise. Since the materials are quite springy, controlling the whole process through heat treating is a real chore. Bob > On Aug 25,

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi The fact is that commercial linear supplies are still out there for pretty cheap prices. The price of a usable switcher is a very small fraction of the price of a Tbolt. Noise on the switcher is a big deal. Not everybody seems to care about low phase noise on the 10 MHz. Switcher frequency

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi It is not that hard to do. Use a linear rather than a switching approach. Run the +12 and +5 supplies off of LT1764 regulators. The -12 is very low current, run it off of a low noise op amp. There are lots of toroidal line transformers that will drive something like this. Bob > On Aug

Re: [time-nuts] Tbolt issues

Hi The GPSDO might have an ADEV of 1 ppt at 1 sec and that rises to 30 ppt at 100 sec. It also might not, but let's use those numbers. ADEV is a standard deviation. You can get an idea of the magnitude of the change reading to reading from it. It does not give you a sign for that change. In

Re: [time-nuts] Tbolt issues

Hi Just to be a bit more clear: This is *not* something unique to the Tbolt. It shows up on all GPSDO's. There have been a lot of posts with data plots showing this on lots of GPSDO's. The issue is more basic than a goof in a control loop setting. To some extent it is a problem on all

Re: [time-nuts] Tbolt issues

Hi Since the measurement in the frequency domain is a "peak" measure, you need to convert both to frequency error and to an absolute max. If you *do* care about the one second per day (or 10 days) as some do, that is a different factor than one second out of two minutes. Since the noise is

Re: [time-nuts] Tbolt issues

Hi The problem is that ADEV is not really the best tool for measuring / modeling narrow band noise. There are other measures that are better. None of them really give you a direct connection to a band limited noise process. Without a model for the process, coming up with a max limit is just

Re: [time-nuts] Tbolt issues

Hi The gotcha in your approach is that you are using more than one sample out of the system to get frequency. Thus you are measuring over a time period. To get instantaneous frequency you need to base it on a single sample. There are some other restrictions (infinite bandwidth being the big

Re: [time-nuts] Z3801A gps week rollover

Hi The rollover is in the GPS module firmware. If you dig into it, they didn't quite update the firmware once every 3 months, but almost that often. Each manufacturer latched onto various versions as they sailed by. None of them had a validation process that could keep up with 4 releases a

Re: [time-nuts] Tbolt issues

Hi Unfortunately if you read a typical text on FM modulation, "instantaneous frequency" comes up pretty fast. In that context it has a valid meaning. Once out of context, it gets you in trouble. That point is never made when the term is introduced. Bob > On Sep 1, 2016, at 8:51 PM, Charles

Re: [time-nuts] Tbolt issues

Hi Frequency is a "change over time". If delta time is zero it is undefined. As you observe it in shorter time periods, the accuracy / stability gets worse. Since the error bars expand there isn't much of a limit as you go shorter. They are not quite the same thing, but they are related. Bob

Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi The easy answer for a couple dozen Tbolts is a +15 V high current linear supply and a low power -15 V linear. Wire them to regulators mounted on chunks of perf board. Bob > On Sep 1, 2016, at 12:24 AM, DaveH wrote: > > Someone could come out with a circuit

Re: [time-nuts] HP-105B Battery Replacement?

Hi They are very common when you look at server UPS or larger units. There are literally hundreds of models to pick between. Prices are from roughly $400 up to a few hundred thousand dollars per unit. Bob > On Sep 15, 2016, at 6:13 PM, Jeremy Nichols wrote: > > Since I

Re: [time-nuts] 53132A triggering

Hi Most PPS signals these days are very low duty cycle. If you AC couple them, you can easily be triggering on the wrong edge. With the narrow pulse it may not be very obvious. Bob > On Sep 16, 2016, at 5:46 PM, Charles Steinmetz wrote: > > Bob wrote: > >> Set it

Re: [time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

e wrong edge. > > Peter > > > >> On 16 September 2016 at 23:55, Bob kb8tq <kb...@n1k.org> wrote: >> >> Hi >> >> Most PPS signals these days are very low duty cycle. If you AC couple > t

Re: [time-nuts] 3D printed sundial displays the time digitally [Youtube Link]

Hi It has been kicking around for about a year. It is a real bear to print. Bob > On Aug 26, 2016, at 12:09 PM, Oz-in-DFW wrote: > > Got this in today's EDN email. Pretty clever, displays time as decimal > digits in 20 minutes increments. > >

Re: [time-nuts] hm H Maser

Hi > On Jan 10, 2017, at 5:26 PM, Bob Stewart wrote: > > This may be a dumb question, but how much of an H Maser's advantage over a Cs > Standard, for us mere mortal time-nuts, is down to the output oscillator it > uses, rather than the reference source (H MASER or Cs beam)?

Re: [time-nuts] hm H Maser

Hi Masers pop up in good (as in new or almost so) condition in the $30 to $70K range from time to time. You *do* need to be a bit lucky, but compared to a decade long development process … not very lucky. The biggest issue with Masers is that there isn’t much of a market. They simply are to

Re: [time-nuts] σ vs s in ADEV

Bob > > Jeremy > > > On Mon, Jan 9, 2017 at 2:00 PM Bob kb8tq <kb...@n1k.org> wrote: > >> Hi >> >> >> >>> On Jan 9, 2017, at 4:49 PM, Magnus Danielson <mag...@rubidium.dyndns.org> >> wrote: >> >>>

Re: [time-nuts] Survey plot as art.

Hi > On Jan 9, 2017, at 6:06 PM, Jay Grizzard wrote: > > Does anyone know of any schematics for amplified GPS splitters floating > around out there? I looked a while back and couldn't find anything. I use a > 58536A right now, but it's big and I hate having to

Re: [time-nuts] σ vs s in ADEV

Hi > On Jan 9, 2017, at 4:49 PM, Magnus Danielson > wrote: > > Scott, > > On 01/09/2017 07:41 PM, Scott Stobbe wrote: >> I could be wrong here, but it is my understanding that Allan's pioneering >> work was in response to finding a statistic which is convergent to

Re: [time-nuts] σ vs s in ADEV

Hi > On Jan 10, 2017, at 1:22 PM, Magnus Danielson <mag...@rubidium.dyndns.org> > wrote: > > Hi Bob, > > On 01/10/2017 12:20 AM, Bob kb8tq wrote: >> Hi >> >>> On Jan 9, 2017, at 5:09 PM, Jeremy Nichols <jn6...@gmail.com> wrote: >>>

Re: [time-nuts] FE-5650A option 58 tuning word for 10 MHz output

Hi In most Rb’s (including the FE 56xx’s) the DDS is mixed with a fixed microwave frequency signal. The DDS only has to make up “part” of the total offset. You get roughly a three orders of magnitude improvement because of this. Rick has gone into all the gory details of why it gets done this

Re: [time-nuts] TAPR Oncore M12+ kit

Hi At least from a quick read of the TAPR page it’s not real clear if the GPS modules are M12+T or just M12+ boards. I believe that if they don’t have the T on the end, they don’t have sawtooth / PPS (?). Bob > On Mar 30, 2017, at 2:11 AM, Mike Cook wrote: > > I would

Re: [time-nuts] GPS first LO need to be locked?

Hi > On Mar 30, 2017, at 7:05 PM, jimlux wrote: > > On 3/30/17 10:32 AM, Bob Camp wrote: >> Hi >> >> There is a limited tracking range for Doppler. You would need to stay inside >> that. >> > > Doppler is pretty big when the spacecraft is coming or going at the

Re: [time-nuts] Time Dilation tinkering

Hi The outer can is at best only “sort of” sealed. Bob > On Mar 22, 2017, at 10:58 AM, jimlux wrote: > > On 3/22/17 4:28 AM, Bob Camp wrote: >> Hi >> >> In this case, the vacuum might work against you. You change the pressure >> outside >> the package and you get a

Re: [time-nuts] PLL Digital Loop Filter

Hi > On Mar 22, 2017, at 7:50 AM, Attila Kinali wrote: > > On Tue, 21 Mar 2017 21:45:24 -0400 > Bob Camp wrote: > >> 1) You need a way to digitize the phase input with adequate resolution. If >> you have a 1 second period and want 1 ns, you need a way to

Re: [time-nuts] PLL performance?

Hi As others have pointed out, a control loop at 100 seconds is more a gain spec than an R/C time constant spec. The real issue is that you should have an integrator on the loop and that *is* an R/C sort of thing. It’s also likely to have a much longer time constant than the magic number for

Re: [time-nuts] Single ended or differential input to TDC chip

Hi Eventually you will want multiple inputs to any chip like this. The more I/o the more crosstalk. Properly done, differential inputs will reduce your crosstalk quite a bit. You might as well debug that part of it now. Bob > On Mar 27, 2017, at 9:05 AM, Attila Kinali

Re: [time-nuts] TAPR Oncore M12+ kit

Hi That’s a very good price for what it is !! Bob > On Mar 27, 2017, at 9:31 AM, Gregory Beat wrote: > > The TAPR offering is a "partial kit" from the Synergy's SynPaQ/E product. > Here is that data sheet: >

Re: [time-nuts] ADEV query Timelab and TICC

Hi It’s a pretty good bet that the “upper” trace has a noise pop in it. One of the wonderful things about ADEV is that a single noise event can impact the whole curve. That is a bit non-intuitive. It is indeed how the math works and how the testing comes out in the real world. Bob > On Mar

Re: [time-nuts] HP-59309A Clock counts only seconds

Hi A lot of the early IC’s were packaged in the era of “learning by doing”. The net result is that some of them do indeed have process related packaging “use by dates”. On top of that the early IC processes were not as fully worked out as the more modern ones. Things like metallization

Re: [time-nuts] The ultraAtomic clock for home

Hi Based on their web site, the model you saw is the one and only version that does the new modulation. One very useful feature is the ability to set it to any time zone world wide. I guess I missed the note on the WWVB coverage area expanding to cover the entire planet …..:) Bob > On Apr 4,

Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

Hi > On Apr 9, 2017, at 10:01 PM, Alex Pummer wrote: > > actually it does not compensate for temperature it is just for reduce the > production cost for the crystal. We --Jean Hoerni [founder of intersil, > Eurosil and one of the traitors who started Fairchild

Re: [time-nuts] HP 105D FS

Hi Are you sure you have the model number right? That does not sound like a 105D … The 105B was a 1960’s creature that had a 5 MHz crystal in it already. Bob (who probably has eight typos in the sentence above :) > On Apr 9, 2017, at 2:46 AM, Perry Sandeen via time-nuts

Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

Hi In my “test environment” car clocks always run fast. That’s been true for many decades over many manufacturers. The idea of putting in an offset on a timekeeping device is an old one. You run the beast over the “expected” temperature (and other environmental) range. You observe how fast or

Re: [time-nuts] The ultraAtomic clock for home

Hi > On Apr 7, 2017, at 10:10 PM, Charles Steinmetz wrote: > > Jim wrote: > >> Charles wrote: > >>> [blob over wire bond construction] >>> is also extremely unreliable, particularly WRT environmental effects >>> such as temperature changes, humidity, and atmospheric

Re: [time-nuts] TAPR TICC boxed (input protection)

;> On Apr 11, 2017, at 7:46 AM, Bob kb8tq <kb...@n1k.org> wrote: >> >> Hi >> >> >>> On Apr 11, 2017, at 7:05 AM, Charles Steinmetz <csteinm...@yandex.com> >>> wrote: >>> >>> David wrote: >>> >>>> I end

Re: [time-nuts] TAPR TICC boxed (input protection)

Hi If anybody gets into this sort of thing in the future — There are black / optical blocking die coat materials out there. They are silicone based and quite stable. We used a *lot* of the stuff on watch modules after it was discovered that the watch died when exposed to a heavy dose of

Re: [time-nuts] a link to a explanation of Rb vs Cs?

Hi Assuming you are doing a “conventional” Rb and Cs there are a number of differences. There is the sub set of doing a gas cell based on Cs which is a lot more similar to Rb. With the Cs, you are building a very complicated vacuum tube that plays with a focused beam of ions traveling in

Re: [time-nuts] Re. DIY atomic "resonator"

Hi If you are going to do a Rb, probably the best place to start is with a salvaged physics package out of one of the telecom Rb’s. That would let you get the “easy bits” worked out on your side of the design. It would also let you lear how to address a few of the more complex items sorted

Re: [time-nuts] TU30 jump second

Hi Welcome to the ever growing list of people with buggy GPS modules. One thing that makes this stuff tough to track down is the firmware. A lot of these parts went out with various revs of the standard firmware. Some of them went out with specific customized versions of the firmware. Since

Re: [time-nuts] TU30 jump second

Hi > On Apr 4, 2017, at 10:01 AM, Bo Hansen wrote: > > Hi all > > The data can be a bit hard to read in an email. So I will give it another try. > > PC-time | Diff. | GPS-time | Diff. > ... > 011606.005 | 0.992 | 011604 |1 > 011607.013 | 1.008 | 011605 |1 > 011608.005 |

Re: [time-nuts] GPS first LO need to be locked?

Hi There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s then (re) sampled from there. The “LO” in this case would down convert to the low IF …. Bob > On Mar 31, 2017, at 6:08 PM, Magnus Danielson > wrote: > > God natt Attila, > > On

Re: [time-nuts] TAPR TICC boxed

Hi If need it, indeed coming up with individual delays is a bit of a pain. One of the most basic decisions is to establish a reference plane. More or less - the signal at “this point” is zero. Everything else is going to be off by nanoseconds from that point (with meter long cables involved).

Re: [time-nuts] TAPR TICC boxed

Hi There are low(fish) leakage / low capacitance / high speed transient suppressor diodes out there. The aren’t going to do anything good in a 1 megohm environment. They are quite useful in lower impedance circuits. Bob > On Apr 1, 2017, at 1:49 AM, Scott Stobbe

Re: [time-nuts] TAPR TICC boxed (input protection)

Hi One interesting “feature” of leakage specs: They often reflect the measurement limit rather than the actual device performance. If they are guaranteed by test, the limit may be orders of magnitude above the actual performance. That’s on top of the likely “rated at max temperature” part

Re: [time-nuts] a link to a explanation of Rb vs Cs?

HI > On Apr 11, 2017, at 6:15 PM, Richard (Rick) Karlquist > wrote: > > The "magic" of Rb in a gas cell standard is that you > can make an optical filter cell out of radioactive > Rb87 isotope that allows you to selectively optically pump > to the quantum level you need.

Re: [time-nuts] a link to a explanation of Rb vs Cs?

HI > On Apr 11, 2017, at 5:57 PM, jimlux <jim...@earthlink.net> wrote: > > On 4/11/17 12:59 PM, Bob kb8tq wrote: >> Hi >> >> Assuming you are doing a “conventional” Rb and Cs there are a number of >> differences. There is the sub set of doing a gas

Re: [time-nuts] Re. DIY atomic "resonator" 6GHz synthesizer from ADI

Hi If you make the cells in the basement (or even in most factories) the ability to have a wide range synthesizer will come in handy. The whole “6.834xxx GHz” thing is dependent on a number of variables. It is not at all uncommon to produce cells that come out 10’s or 100’s of KHz off of the

Re: [time-nuts] Re. DIY atomic "resonator"

Hi According to the data sheet the X version of the 2400 has a TCXO in it. The “not an X” has an XO. “Setability” of the XO is <0.5 ppm and the TCXO is rated at 0.2 ppm. Maximum resolution on the device occurs with a 20 MHz input. That gives you +/- 0.05 ppm. The 200 MHz range is scaled by 10

Re: [time-nuts] a link to a explanation of Rb vs Cs?

Hi If you take a look at the standard weekly publications, the GPS system runs on Rb’s. There is always one sat that has a Cs turned on. That’s been true as long as they have been running the system. The simple answer for that choice is that the Rb’s are easier to predict (better short term to

Re: [time-nuts] Looking for Gen Rad 1101A oscillator/parts

Hi Does your unit have the 1190 100 Kc quartz bar still in it? If so does the mount appear to be intact? At this late date, replacing that resonator is not going to be easy. Bob > On Apr 6, 2017, at 3:58 PM, jmfra...@cox.net wrote: > > I am trying to restore a clunker General Radio 1101A

Re: [time-nuts] CSAC vs NAC1

Hi If you set them both on the table, the CSAC’s I’ve seen are just slightly smaller than the NAC’s. It’s not by much. I never bothered to see if the mechanical specs on the parts reflected this or not. Bob > On Apr 6, 2017, at 10:41 PM, jimlux wrote: > > On 4/6/17

Re: [time-nuts] Sinlge ADC multi-band receiver

Hi Galileo E5 is a bit of a strange case. It’s really E5a and E5b. You can either grab it all as one giant signal or as two separate signals. You may (or may not) care about the data on E5a or b depending on what you are trying to do. Getting the entire very wide signal likely has some

Re: [time-nuts] Line Frequeny Stablity

verage very close to 60.000 Hz. They saw I had an interest > and offered me one of their toys. The only thing it doesn't do is connect > to my PC so I can monitor it long-term. I suppose if I were clever with > network stuff there'd be a way to tap into its data stream. > > Jeremy,

Re: [time-nuts] Spirent STR4500 GPS simulator

Hi Just to clarify a bit: These gizmos fall into two broad categories: 1) The single sat simulators like the GSS6100 that show up cheap. 2) The full constellation simulators that show up for a bit more money. The single sat stuff is simple to run from a serial port and limited in function.

Re: [time-nuts] Spirent STR4500 GPS simulator

Hi To the extent that the device runs like a 4100 or a 6100, it does not need any software to support it. The same may be true of the 6300. They all run from a drop dead simple serial command set. On the 6100 you fire up a terminal program at 38.4 K baud 8N1 and type away. All of the features

Re: [time-nuts] The ultraAtomic clock for home

Hi > On Apr 5, 2017, at 9:00 AM, Jim Harman <j99har...@gmail.com> wrote: > > On Wed, Apr 5, 2017 at 7:30 AM, Bob kb8tq <kb...@n1k.org> wrote: > >> I’m still a bit unclear on how many people will set up a wall of clocks >> running >> on a dozen or

Re: [time-nuts] The ultraAtomic clock for home

Hi The Lacrosse wall clocks I’m using now are hybrid analog / digital displays. You get the time analog and the date off the digital display. For whatever reason, that model is now history. Bob > On Apr 5, 2017, at 11:30 AM, Richard (Rick) Karlquist > wrote: > >

Re: [time-nuts] Spirent STR4500 GPS simulator

Hi > On Apr 5, 2017, at 1:36 PM, Magnus Danielson > wrote: > > Hi Phil, > > I just wanted to chime in an make a note that the STR4500 seems to have USB > connection rather than serial. The manual mentions installing a driver. I > wonder if the USB port is

Re: [time-nuts] HP 100D FS [WAS: HP 105D FS]

HI If you take a look at the schematic of the oscillator circuit shown in the HP Journal article, it is the standard circuit that is used in just about every microprocessor clock and clock oscillator made (except for the vacuum tube …) No, it’s not the earliest example, but it is pretty early by

Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

Hi The compensation process either for a clock or a watch has been embedded in the IC for a lot of years now. They do a pulse add / pulse drop approach to “level out” the 1 pps drive to the display. Temperature does not move fast enough that averaging things over a minute is an issue. That gives

Re: [time-nuts] HP 105D FS

d.. > > Sorry for the brain fart. > > Regards, > > Perrier > > > On Sunday, April 9, 2017 5:18 AM, Bob kb8tq <kb...@n1k.org> wrote: > > > Hi > > Are you sure you have the model number right? That does not sound like a 105D > … The 105B was a 1960’s

Re: [time-nuts] HP 100D FS [WAS: HP 105D FS]

Hi The “heated crystal” approach was pretty common up until the 1970’s. Both GR and HP moved over to "electronics in the oven” at about the same time(early 60’s) for rack mount standards. There are a few tube based OCXO’s with heated electronics. Some of them date to the 1960’s others appear

Re: [time-nuts] Car Clock drift - the lowly 32kHz tuning fork crystal specs

Hi > On Apr 9, 2017, at 11:36 AM, Clint Jay wrote: > > The clocks in my car have been set by the RDS data, DAB data or GPS in the > last five or six I've had. Drift is a thing of the past as long as i listen > to digital radio or the BBC on analogue FM, if i listen to

Re: [time-nuts] Sinlge ADC multi-band receiver

> On Apr 9, 2017, at 4:29 PM, Attila Kinali <att...@kinali.ch> wrote: > > On Wed, 5 Apr 2017 08:27:58 -0400 > Bob kb8tq <kb...@n1k.org> wrote: > >> Galileo E5 is a bit of a strange case. It’s really E5a and E5b. >> You can either grab it all as one

Re: [time-nuts] Sinlge ADC multi-band receiver

HI > On Apr 9, 2017, at 4:28 PM, Attila Kinali wrote: > > On Tue, 4 Apr 2017 17:58:11 -0700 > jimlux wrote: > >>> The advantage of such a system would be that there is only a single >>> path through the system for all signals, especially through the

Re: [time-nuts] Sinlge ADC multi-band receiver

Hi > On Apr 10, 2017, at 1:00 AM, Magnus Danielson > wrote: > > God Morgon Attila, > > On 04/09/2017 10:28 PM, Attila Kinali wrote: >> On Tue, 4 Apr 2017 17:58:11 -0700 >> jimlux wrote: >> >> The beauty of the system would be that you don't

Re: [time-nuts] TAPR TICC boxed (input protection)

Hi Testing can mean a lot of different things. Did they test every single part they shipped for every parameter? Did they just do a sample of parts and decide the lot was good? Did they test a sample of parts for a sub-set of the specs and decide they were good? Did they test them after

Re: [time-nuts] TAPR TICC boxed (input protection)

Hi > On Apr 11, 2017, at 7:05 AM, Charles Steinmetz wrote: > > David wrote: > >> I ended up qualifying 2N3904s based on manufacturer and lot and I >> think we ended up using ones from Motorola. I wish detailed process >> information like National had was available from

Re: [time-nuts] Re. DIY atomic "resonator"

Hi *All* incandescent lamps emit RF ….. They are a resistive device that is heated to well above room temperature. People do use them in simple noise figure meters. The inductance of the filament in a typical bulb restricts the bandwidth a bit. The are designs from at least the 1960’s

Re: [time-nuts] Re. DIY atomic "resonator"

Hi There are papers from the mid 90’s talking about improving the GPS Rb’s. Those parts are as far as I know the best “production” Rb’s out there. The main comment seems to be that phase noise (in it’s various forms) is a major contributor to the stability of the Rb’s…. Bob > On Apr 12,

Re: [time-nuts] OCXO Soft-Start

Hi A SC cut crystal has multiple resonance “modes” in can operate on. This is in addition to the normal set of fundamental, third overtone, fifth overtone and so on. For various interesting reasons the SC modes are called A, B and C. On a normal 10 MHz crystal, the “main mode” is the C mode.

Re: [time-nuts] Mini-circuits ZFSC-8-1 a a reference distribution

Hi A lot depends on what you are trying to do. The disadvantage of power splitters is isolation. A dirt cheap logic IC based distribution amp will easily beat them in this regard. That said, the splitters are quite easy to find and hook up.They also are pretty much indestructible (at least I’ve

Re: [time-nuts] noise sources Re: Re. DIY atomic "resonator"

PM, jimlux <jim...@earthlink.net> wrote: > > On 4/12/17 1:23 PM, Bob kb8tq wrote: >> Hi >> >> >> *All* incandescent lamps emit RF ….. They are a resistive device that is >> heated to well above >> room temperature. People do use the

Re: [time-nuts] OCXO Soft-Start

Hi If your MCU has a POR that resets the internal oscillator that’s an unusual part. Most of them I’ve seen simply reset the CPU…..Once the 8 MHz crystal oscillator is running at 37 to 53 MHz (or KHz) it may or may not ever return to 8 MHz on it’s own. Yes, you need to get into some nutty

Re: [time-nuts] Three-cornered hat on timelab?

34310-T) could you please share it with me? I'm looking for relative > peformance, not a definitive test. Of course if you also have one of a > 34310-T against the same standard, that would be great! > > Bob > > > > From: Bob kb8tq <kb...@n1k.org> > To: Bo

Re: [time-nuts] Three-cornered hat on timelab?

Hi There are a number of papers from the 70’s and 80’s digging into three corner hat data. The net result often would turn out to be “less than zero” noise on one of the DUT’s. Since that’s physically impossible the technique got a bit of “attention”. The Cliff Notes version of the results is

Re: [time-nuts] OCXO Soft-Start

supply is current or power limited the effective supply slew rate > is something like 1 mV/s, and under these conditions, at least this > particular unit starts up on B-mode every time. > > Running one of these on a USB supply (5V, 500mA = 2.5W) is looking > plausible. > > On Wed, Apr

Re: [time-nuts] noise sources Re: Re. DIY atomic "resonator"

nk.net> wrote: > > On 4/12/17 6:33 PM, Bob kb8tq wrote: >> Hi >> >> Back in the day (1960’s) noise diodes were quite a bit more expensive than >> they are today. Even >> today, a miniature lightbulb is quite a bit less expensive than a noise >> diode. Y

Re: [time-nuts] Mini-circuits ZFSC-8-1 a a reference distribution

Hi If the circulators are good to 10 MHz and you have eight of them to play with, then certainly they can be turned into isolators. Unless you have a really unique source of them, that kind of gets this out of the cheap seats. The “why” of isolation is very application dependent. Without

Re: [time-nuts] Measuring coax temperature coefficient with a TICC

Hi One of the easiest ways to get a slow ramp it to toss the foam box full of cable out the back door. Assuming it stays in the shade, you can often get a pretty good 24 hour temperature cycle. You still need to monitor things to know what the ramp is. Generally it’s slow enough that you can

Re: [time-nuts] Name of integral of timing residual

Hi Hi I think your “quest” to find the terms as they relate to motion is a pretty good example of just how unusual these terms are. Once you go past displacement, they are hardly common vocabulary. My guess is that nobody has ever come up with terms in the time domain that have made it into the

Re: [time-nuts] Name of integral of timing residual

Hi On a normal GPSDO holdover spec, you are concerned with the maximum time error over a specified period. Generally it’s going to be a 24 hour holdover, but it can be longer or shorter depending on the application. The good old CDMA spec got out into the 10 to 11 us range at 24 hours. Various

Re: [time-nuts] Three-cornered hat on timelab?

eric swings on my GFS unit that you > and Bruce and others have spoken about. This bothers me a lot. Could it be > my location here in Houston? Could it be the Ublox LEA-6T compared to the > much older Motorola in the KS? > > Bob > > > > From: Bob kb8tq <kb...@

Re: [time-nuts] Three-cornered hat on timelab?

<b...@evoria.net> wrote: > > Hi Bob, > > OK, thanks. I've kicked off a 7 day run of a GFS against the PRS-45A. That > should be long enough to separate out the GFS from the PRS' drift direction > from the ionosphere. > > Bob > > > > > > F

Re: [time-nuts] Measuring coax temperature coefficient with a TICC

Hi > On Apr 19, 2017, at 2:57 PM, Hal Murray wrote: > > > kb...@n1k.org said: >> I’d want to be pretty sure what the center conductor was made out of. I’ve >> seen some stuff in coax that “one would think” should not be there (copper >> over steel …). > > Does that

Re: [time-nuts] Measuring coax temperature coefficient with a TICC

Hi > On Apr 18, 2017, at 8:33 PM, jimlux <jim...@earthlink.net> wrote: > > On 4/18/17 3:55 PM, Bob kb8tq wrote: >> Hi >> >> On something like a 500’ spool of coax, the question will always be “what >> temperature is it where in the spool”. A sing

Re: [time-nuts] Frequency counter questions

Hi > On Apr 23, 2017, at 2:43 PM, Chris Albertson <albertson.ch...@gmail.com> > wrote: > > On Sun, Apr 23, 2017 at 7:38 AM, Bob kb8tq <kb...@n1k.org> wrote: > >> >> >> If you want to do something like the 53131 or even the 5335, you will nee

Re: [time-nuts] Frequency counter questions

Hi > On Apr 23, 2017, at 12:43 PM, Richard Solomon wrote: > > At that resolution, you need a very accurate and stable Time Base. > > A GPSDO may not be good enough for 10 e12 measurements. > If buy some truly strange chance, this *is* a 100,000 second gate time exercise

Re: [time-nuts] Frequency counter questions

Hi Counting 12 digits is relatively easy, if that is the only constraint. Bring your “signal” into one of the timer clock inputs on the MCU. If your “signal” is 10 MHz that will be simple. If it’s 30 GHz it will be more difficult. 10 MHz gives you 7 digits a second. To get to 12 digits, you

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