Re: [time-nuts] 53132 replacement fan

Hi The bigger issue when you replace the fan: Do the best job you possibly can cleaning out the power supply. Also check the soldering and the rest of the workmanship on the power supply pc board. It’s the weak link in the counter. You don’t have to give it much of a look to figure out HP

Re: [time-nuts] Need for a document comparing time interval counters

Hi With both counters running on the same external standard (and no internal OCXO), the 53230 beats the 53132 both on frequency and time. It also has slightly better isolation of the 10 MHz internals so the “dead zone” at 10 MHz is not quite as bad. I have no idea how either one works with

Re: [time-nuts] Do reflections up/down the antenna cable cause a problem with GPS?

Hi Based on extensive testing of the line mismatch issue, the answer turns out to be “it does not matter”. The reflection issue ahead of the antenna is a reflection of the signal from a single satellite. The multipath reflection makes that satellite appear to be further away than it really

Re: [time-nuts] Inductor core material aging (was: Rohde & Schwarz XSD 2.5 MHz crystal gone bad?)

Hi > On Nov 21, 2016, at 9:23 AM, Attila Kinali <att...@kinali.ch> wrote: > > Hoi Bob, > > On Sun, 20 Nov 2016 22:21:29 -0500 > Bob Camp <kb...@n1k.org> wrote: > >> 50 year old inductors may have been made with core materials >> that aged more

Re: [time-nuts] How can I measure GPS Antenna quality?

Hi At spectrum analyzer bandwidths, the GPS signals out of the antenna are more than 20 db below the noise floor. You can’t see them with an analyzer. You need to run things into the equivalent of a receiver to turn it into anything you can see above the noise. What you will see on an

Re: [time-nuts] Rohde & Schwarz XSD 2.5 MHz crystal gone bad?

Hi If the frequency drops as the oven warms up, you have an AT cut crystal. If the frequency goes up as the oven warms up, you have a BT cut crystal. With an AT or a BT, the frequency change between room and “hot” will depend a lot on the details of the proper oven temperature. A frequency

Re: [time-nuts] HP 55300A

Hi At normal room temperatures, you simply can not run enough air past the OCXO to “cool it to much”. The OCXO heater will simply put out a bit more power as you increase the air flow. That’s not to say that the performance will improve any as the OCXO is quickly following any twitch or bump in

Re: [time-nuts] Need for a document comparing time interval counters

Hi Once you get into used gear that is many decades old, the actual performance of *your* counter is likely to be different than the performance of mine. If you are willing to go through all of the detailed alignment steps (and possibly replace parts) yours will work better than mine. How

Re: [time-nuts] Excel logarithmic function (was Thermal impact on OCXO)

Hi In a conventional fit situation, you have < 30 days worth of data and the “time constant” is > 30 days. Put another way bt <= 1 in the normal case. It is only when you go out to years that bt gets large. Bob > On Nov 18, 2016, at 9:58 PM, Scott Stobbe wrote: > >

Re: [time-nuts] Thermal impact on OCXO

have some ideas what is > going on?? > > Lars > > >Från: Bob Camp > >Skickat: den 17 november 2016 01:03 > >Hi > > >Your data demonstrates a couple of things: > > >1) There are a number of different things going on with that OCXO and

Re: [time-nuts] Excel logarithmic function (was Thermal impact on OCXO)

Hi > On Nov 18, 2016, at 4:36 PM, Magnus Danielson > wrote: > > Hi Lars, > > Now, consider f(t) = a*log(b*t+1), then the derivate is a*b/(b*t+1) and > second derivate - a * b^2 / (b*t + 1)^2. > > Forming first f'(t) and second f"(t) derivate estimates from data

Re: [time-nuts] precision timing pulse

Hi If you head of into ARM land (or even FPGA’s) there is a bit of a gotcha. If you want to run a 10 MHz input and a PPS output, you need a counter with at least 24 bits. The peripherals on ARM chips are all over the place. Some have very fancy timers, but only go to 16 bits. Some have 32 bit

Re: [time-nuts] precision timing pulse

Hi There are a number of us on the list who code on ARM MCU’s. Doing the same thing on one of them is *not* a trivial undertaking. Making sure that it does what it should simply is not worth the effort. The PIC 12 is a low cost solution and has been extensively tested to show that it does what

Re: [time-nuts] Thermal impact on OCXO

> AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > From: Bob Camp <kb...@n1k.org> > To: Discussion of precise time and frequency measurement <time-nuts@febo.com> > Sent: Thursday, November 17, 2016 11:39 AM > Subject: Re: [ti

Re: [time-nuts] Thermal impact on OCXO

large OEM’s. The sort consists of “ship these” and “send these to the crusher”. Needless to say, the emphasis is on a process that throws out as few as possible. Bob > > On Wed, Nov 16, 2016 at 8:06 PM, Bob Camp <kb...@n1k.org> wrote: >> Hi >> >> The issue in fitting ove

Re: [time-nuts] precision timing pulse

Hi > On Nov 16, 2016, at 11:52 PM, jimlux wrote: > > On 11/16/16 7:17 PM, Hal Murray wrote: >> >> t...@leapsecond.com said: >>> Arduino probably uses compiled code, external libraries, and interrupts so >>> that also is a no-no for precise time. >> >> There are two

Re: [time-nuts] Thermal impact on OCXO

54 5.83990.0031886 > 0.022782 9.8582 -0.0074089 > 0.023279 3.7392 0.012161 > 0.02345 4.10620.0095448 > > The only other thing to point out from this, is that the A2 and A3 > coefficients are highly non-orthogonal, as A2 increases, A3 d

Re: [time-nuts] Thermal impact on OCXO

Hi Your data demonstrates a couple of things: 1) There are a number of different things going on with that OCXO and some things are a lot less predictable than others. 2) Oscillators do drop rate while on power. 3) Oscillators that age a lot are easier to model (yes, that OCXO is aging a lot

Re: [time-nuts] Excel logarithmic function (was Thermal impact on OCXO)

Hi As mentioned earlier in this thread. The function that has been used in several posts isn’t the right log function. The proper fit is to ln(bt+1) Bob > On Nov 16, 2016, at 4:36 PM, Peter Vince wrote: > > Hello Lars, > > Just out of curiosity I yesterday put just

Re: [time-nuts] Thermal impact on OCXO

nalysis process are > establishing a satisfactory iteration factor and error criterion to assure > both convergence and small residuals." > > http://www.stable32.com/Curve%20Fitting%20Features%20in%20Stable32.pdf > > Not sure what others do. > > > On Mon, Nov 14

Re: [time-nuts] Thermal impact on OCXO

Hi If you already *have* data over a year (or multiple years) the fit is fairly easy. If you try to do this with data from a few days or less, the whole fit process is a bit crazy. You also have *multiple* time constants involved on most OCXO’s. The result is that an earlier fit will have a

Re: [time-nuts] Secondary phase noise standard & FE405

Hi The “sure fire” way to reduce the spurs is to go to a divisor that “fits” in to the DAC bit width. If you have a 12 bit dac, those points happen at Fclock / 2^12. For Time Nut sort of stuff that’s pretty coarse tuning. Bob > On Nov 13, 2016, at 11:03 AM, Tim Shoppa

Re: [time-nuts] quartz drift rates, linear or log

Hi > On Nov 13, 2016, at 9:34 AM, Artek Manuals wrote: > > Tom et all > > While our instinct based on some "pre- knowledge" of the aging and drift > processes is to try and fit these to linear or logarithmic curves there is a > third possibility . That is, in fact

Re: [time-nuts] Secondary phase noise standard & FE405

Hi > On Nov 13, 2016, at 2:55 AM, Gerhard Hoffmann <dk...@arcor.de> wrote: > > Am 12.11.2016 um 23:52 schrieb Bob Camp: >> Hi >> >> Yes, the FE-405 uses a DDS and a cleanup. Inside the cleanup loop the DDS >> spurs come >> straight through. Since t

Re: [time-nuts] quartz drift rates, linear or log

Hi Exact info on mass transfer is a bit complicated. A 5 MHz 5th overtone is a bit thicker and more massive than a 100 MHz 5th. Both are thicker (and more massive) than a 100 MHz fundamental. On top of that the blank is not equally sensitive to mass at all points on it’s surface. Finally, gold

Re: [time-nuts] Secondary phase noise standard & FE405

Hi It depends both on the DDS “firmware” and the DAC linearity. You can play games to come up with the firmware side of it. The normal approach is to design the part so the DAC dominates. More or less, "more firmware bits” is cheaper than improving the DAC. Bob > On Nov 12, 2016, at 8:13

Re: [time-nuts] TCXO drift - related to TVB's posting

Hi In *general* the crystal in an OCXO should drift positive. The reason often mentioned is fairly simple: You can only get the blank + base plate + calibration just so clean. You can go crazy getting the enclosure clean. The result is a long term mass transfer from the blank (it’s “dirty”,

Re: [time-nuts] Secondary phase noise standard & FE405

Hi Yes, the FE-405 uses a DDS and a cleanup. Inside the cleanup loop the DDS spurs come straight through. Since the FE-405 compensates for all sorts of things, the DDS moves around a lot. Even a one bit change on a DDS will move spurs around. With an ever changing DDS, you have an ever

Re: [time-nuts] quartz drift rates, linear or log

Hi One would *guess* that the OCXO’s all left the factory set to center at zero volts on the EFC. One thing that is pretty easy to do is to look at the date code on the OCXO and the EFC voltage. That plus the sensitivity (one could cheat and look at the frequency rather than EFC) will give

Re: [time-nuts] Swagelok and metric tubing question

Hi The first thing that comes to mind with copper and stainless is that they are not quite the same thing electrolytically (you make a battery). That can be ok, or pretty bad depending on how wet your environment is. There may be other issues …. Bob > On Nov 11, 2016, at 8:57 PM,

Re: [time-nuts] Swagelok and metric tubing question

Hi https://www.mcmaster.com/#9811T14 https://www.mcmaster.com/#50365K33 First one is a 2 mm wall at $75 a chunk. Second one is 1.5 mm at $33 a chunk. It’s not obvious why one is “compression fitting” and the other is “weld” rated. In any case, I suspect you need the 2X more expensive, done

Re: [time-nuts] Need some wisdom from the cesium beam tube gurus out there

gt; wrote: > > If you want sub degree precision, you will need to make your connections to > dissimilar metals on an isothermal boundary, a terminal block is better > than clips in free air. > > On Fri, Nov 11, 2016 at 8:28 AM, Bob Camp <kb...@n1k.org> wrote: > >&

Re: [time-nuts] Need some wisdom from the cesium beam tube gurus out there

Hi > On Nov 11, 2016, at 8:02 AM, jimlux wrote: > > On 11/10/16 10:28 PM, Mike Millen wrote: >> It would work as well if you used a pair of regular copper wires to >> connect the meter to the thermocouple... >> >> The junctions created by all the new connections will

Re: [time-nuts] Nutty time-nuttery with WWVB

Hi > On Nov 10, 2016, at 4:52 PM, Ruslan Nabioullin wrote: > > On 11/10/2016 07:18 AM, Peter Reilley wrote: >> I have a few of those "atomic" clocks that receive WWVB to set the time. >> However since I live on the east coast they may only pick up the signal >> once or

Re: [time-nuts] Nutty time-nuttery with WWVB

Hi This is worth repeating…. > On Nov 10, 2016, at 11:03 AM, Charles Steinmetz wrote: > > Peter wrote: > >> Could I implement my own personal WWVB transmitter that would >> be powerful enough to be picked up by the clocks in my house? >> * * * >> Has anyone

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

Hi Well, I have yet to test a gps module that does not have a *very* accurate pulse width out of it. Same with GPSDO’s. Yes, It’s something I look at. Bob > On Nov 10, 2016, at 10:22 AM, Chris Albertson > wrote: > > The problem here is "real world". Yes in theory

Re: [time-nuts] China Oscillator Alternative

> > See the text I linked to a few days ago. > > >> >> >> On 11/9/2016 7:18 PM, Perry Sandeen via time-nuts wrote: >>> List, >>> After all the problems that Bob Camp has noted with surplus OCXO's from >>> China, perhaps buyin

Re: [time-nuts] Need some wisdom from the cesium beam tube gurus out there

Hi I would bet that they started as you have with a low oven setting and cranked it up based on stability data. Once they got to that point, add a bit to have enough margin on the tube for it to last the rated life. Since there are multiple quantum “modes” the beam can get into, there may

Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

Hi > On Nov 9, 2016, at 6:28 PM, Bob Stewart wrote: > > Tom, > How many times have people posted here, on time-nuts, not to trust the > trailing edge of a 1PPS pulse? The rest of the caution is : The leading edge is the one that is “on time” and the second edge is an

Re: [time-nuts] Thermal impact on OCXO

; the process) there was enough off time to thoroughly insult the OCXO. > > Bob > > - > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > > From: Bob Camp <kb...@n1k.o

Re: [time-nuts] Thermal impact on OCXO

an just to temperature transients? > > Bob - > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > From: Bob Camp <kb...@n1k.org> > To: Bob Stewart <b...@evoria.net&g

Re: [time-nuts] Thermal impact on OCXO

the past 3 or so days of > data collection to project the near-term behavior; where near-term is less > than 3 days into the future. > > Bob > > - > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/n

Re: [time-nuts] Thermal impact on OCXO

Hi > On Nov 7, 2016, at 12:45 PM, Chris Caudle wrote: > > On Mon, November 7, 2016 11:41 am, Chris Caudle wrote: >> On Mon, November 7, 2016 11:20 am, Bob Stewart wrote: >>> Either then OCXO is making up for the temperature change >>> by increasing the temperature >> >>

Re: [time-nuts] Thermal impact on OCXO

Hi Ok, You have a thermocouple junction at the + post on the DVM. You have one at the - post on the DVM. You have a junction at the + connection to the board. You have a junction at the - connection to the board. There are indeed more than that, but those four are pretty much a sure thing.

Re: [time-nuts] Thermal impact on OCXO

Hi > On Nov 5, 2016, at 10:43 PM, Bob Stewart <b...@evoria.net> wrote: > > Hi Scott, > D'oh. Thanks for the correction! Like I said, I don't do these calculations > often. > > If as Bob Camp implies, the aging isn't from the OXCO, then I'm a bit > stumped.

Re: [time-nuts] Thermal impact on OCXO

--- > AE6RV.com > > GFS GPSDO list: > groups.yahoo.com/neo/groups/GFS-GPSDOs/info > > > From: Bob Camp <kb...@n1k.org> > To: Bob Stewart <b...@evoria.net> > Sent: Saturday, November 5, 2016 8:46 PM > Subject: Re: [tim

Re: [time-nuts] Thermal impact on OCXO

Hi 2^20 is roughly 1 ppm. It is about 5 uV on a 5V line or 2.5 uV on a 2.5 V EFC center. A DAC that does 100 ppm / C is a pretty typical part. 10 ppm / C is unusually good A “good” voltage reference might do 2 ppm / C A very typical room will swing around +/- 2C without much

Re: [time-nuts] I love the smell of tantalum in the morning

Hi A *lot* depends on how many planes there are in that board. The weight of he copper also maters a bit. If there is enough thermal mass, you will need a pre-heat process. There are lots of ways to do it ranging from the kitchen oven to various “frame and lightbulb” setups and on into ever

Re: [time-nuts] Thermal impact on OCXO

Hi Remember - most holdover specs also include a delta temperature (like 40 to 70C) during the holdover period …. Bob > On Nov 5, 2016, at 12:15 PM, Bob Stewart wrote: > > Hi Scott and Bob and others, > I keep telling myself that I won't get involved with the temperature

Re: [time-nuts] Thermal impact on OCXO

Hi You have a first order, second order and third order coefficient to the temperature rate dependance on a crystal. Since the second order term is a square, it does not care about the sign of the rate. Bob > On Nov 4, 2016, at 9:56 PM, Bob Stewart wrote: > > In the

Re: [time-nuts] Man with too many clocks.

HI If you use a good wire wound pot and run it off of and oscillator EFC source (not all have them), the temperature effect is pretty much zero. You are using the pot as a ratio device. A mechanical cap that is part of the heated region of the OCXO (the normal case) has already been taken

Re: [time-nuts] Man with too many clocks.

ere is a reason counters don't let you digitally > calibrate beyond that, the 10 MHz ref out on the rear panel would still be > out of cal. > > On Fri, Nov 4, 2016 at 1:48 PM, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >> The only practical way to set the 10

Re: [time-nuts] Man with too many clocks.

Hi The only practical way to set the 10811 or 10544 is with a >= 10 turn pot on the EFC. I never have worked out just why there are so many instruments that don’t have a pot on the EFC. Bob > On Nov 4, 2016, at 11:35 AM, Peter Reilley wrote: > > I gave up on trying

Re: [time-nuts] Thinking outside the box a super reference

AM, Scott Stobbe <scott.j.sto...@gmail.com> wrote: > > You will also share the same challenges as Touchstone semi did, no one > wanted to stick their neck out to design in a little startup. > > On Thu, Nov 3, 2016 at 7:49 PM, Bob Camp <kb...@n1k.org> wrote: > >

Re: [time-nuts] Thinking outside the box a super reference

Hi Ok, how many full performance Hydrogen Masers can you build (size is not an issue) and deliver for < $10,000 (2X Bert’s number) ? Bob > On Nov 3, 2016, at 8:55 PM, Tim Shoppa wrote: > > It would obviously be larger than a homebrew Cs, but why not a homebrew >

Re: [time-nuts] Thinking outside the box a super reference

something better than a 5065 for a thousand or two dollars, it would be on the market today. Bob > On Nov 3, 2016, at 6:34 PM, Attila Kinali <att...@kinali.ch> wrote: > > On Thu, 3 Nov 2016 16:54:24 -0400 > Bob Camp <kb...@n1k.org> wrote: > >> If you look a

Re: [time-nuts] Thinking outside the box a super reference

idnt appear particularly challenging nor did the locking of the laser to the > relevant wavelength using an auxiliary rubidium vapour cell.IIRC thee > performance was better than the telecom market rubidium standards. > Bruce > > On Friday, 4 November 2016 11:34 AM, Attila Kinali &

Re: [time-nuts] Thinking outside the box a super reference

Hi Since you can *buy* a working Rb that runs to a given level. My assumption is that the objective is to do something that is significantly better than you can get for $100 or less. I see no point in setting up to build a device that it 10X worse and costs 10X more money. Making the

Re: [time-nuts] Man with too many clocks.

Hi If your TCXO is off by 1 ppm, it will slip 10 cycles per second at 10 MHz. If it is off by 0.1 ppm it will slip a full cycle at 10 MHz. If it is off by 0.01 ppm *and* uses some sort of digital compensation, it will hop around. If the GPS is not sawtooth corrected it will hop by a good

Re: [time-nuts] So what’s inside that Cs Beam Tube anyway?

Hi Quite literally 10’s of millions of dollars (back in the good old days) was put into the idea of a rebuildable Cs tube or rebuilding ones that already exist. The result was more people in the tube business for a while. They never did come up with a rebuildable tube or a salvage process. Since

Re: [time-nuts] Looking for a low power very low noise DC/DC converter (100 - 200 ma 10VDC or 15VDC)

Hi …. or you could do a milled box inside a milled box inside a milled box. Isolate each one from the others. Filter all leads at each “goes in” and each “goes out”. Put the input side in it’s own cavity in each box. Put the output side in it’s own cavity. Put the control signals in their own

Re: [time-nuts] Temp/Humidity control systems?

Hi A multi mode resonant cavity is probably the “easy” approach. Like the waveguide, it is pressure / temperature / humidity sensitive. The same “can I separate the effects” issue applies. Any enclosed device will have issues with properly representing the humidity in the room. It’s

Re: [time-nuts] theoretical Allan Variance question

Hi There are entire (big and heavy) books written on quantization errors….. In a counter, there are a number of different sub-systems contributing to the error. Depending on the design, each may ( or may not) be a bit better than absolutely needed. Toss in things like 10 MHz reference

Re: [time-nuts] Has anybody checked this? GPSDO in kit

Hi Any pole mount outdoor antenna with a gain in the 20 to 30 db range should be fine with any of these units. Cable loss can be an issue if it is getting the net gain down below 10 db (antenna gain - cable loss). The frequency is 1.5 GHz so a quick look at the standard tables should give you an

Re: [time-nuts] theoretical Allan Variance question

Hi Well, situation one: You have two perfect sources. Your measuring device is noiseless If your devices are in perfect sync, you get a series of zeros Your ADEV is zero Situation two: Same sources Noisy measuring device You get the standard deviation of the difference in measurements Your

Re: [time-nuts] Opening an Isotemp OCXO

Hi If the OCXO was designed for a ~70 C upper end temperature spec, then a ~90C crystal would make sense. When you feed +12 into the oven control, you are increasing the effective gain of the control loop (it has more power). The cycling you see is the loop going into oscillation. It’s the

Re: [time-nuts] WWV receivers?

Hi Let’s see…. WWV (not WWVB) gets here via a variety of propagation mechanisms that vary over the day. According to NIST (who probably know :) that puts a random timing variation of ~1 ms on the signal. Since some modes get me a signal and others don’t, there is no real reason to assume it is

Re: [time-nuts] Unexpected problem found

HI Probably what is going on is that the OCXO’s have a parasitic oscillaton in the UHF region. It has injection locked to the 10 MHz. You get a signal that is much higher level than any harmonic relation would predict. I’d try fiddling the bypassing and load …. Bob > On Oct 28, 2016, at

Re: [time-nuts] Opening an Isotemp OCXO

ies, but given the right tools and employees... > > Bob > > From: Bob Camp <kb...@n1k.org> > To: pe...@reilley.com; Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Sent: Friday, October 28, 2016 2:46 PM > Subject: Re: [time-nuts] Ope

Re: [time-nuts] Opening an Isotemp OCXO

Hi Roughly 99.9% of all OCXO’s made go to large OEM customers. The percentage may actually be a bit higher than that. There are relatively few markets that “catalog” OCXO’s sell into. Inevitably the first thing that an OEM wants is some form of customization. A specific supply voltage, a

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

HI Roughly 99% of it is buried away in the heads of a few dozen people around the world. Bob > On Oct 28, 2016, at 4:24 AM, Attila Kinali <att...@kinali.ch> wrote: > > Hoi Bob, > > On Thu, 27 Oct 2016 19:50:46 -0400 > Bob Camp <kb...@n1k.org> wrote: >

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

ist > <rich...@karlquist.com> wrote: > > > > On 10/27/2016 4:50 PM, Bob Camp wrote: >> Hi >> >> Crystals are highly optimized for the specific overtone they are >> intended to operate on. In fact, you can fiddle them to the point >> that th

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

> wrote: > > Hi, > > Hmm, such fiddeling could maybe also apply to nearby alternative modes of the > crystals, even if I guess it would be harder to do meaningful dents on them. > > Cheers, > Magnus > > On 10/28/2016 01:50 AM, Bob Camp wrote: >> Hi >&

Re: [time-nuts] Difference in manufacturing for fundamental tone, 3rd, and 5th overtone crystals

Hi Crystals are highly optimized for the specific overtone they are intended to operate on. In fact, you can fiddle them to the point that they no longer have a “fundamental” response. Bob > On Oct 27, 2016, at 6:42 PM, Attila Kinali wrote: > > Moin, > > I have stumbled

Re: [time-nuts] Temp/Humidity control systems?

Hi Ok, take this with a bit of caution …. Your “time cave” does not have a specific spec on temperature or on humidity. You get to pick a number for either one. Anything in the “non condensing” (let’s call it < 80%) range for humidity is likely ok. Temperature up to 40C is probably ok for

Re: [time-nuts] Temp/Humidity control systems?

HI I would take a look at the “stuff” they make for wine cellars. It’s an application aimed at the same sort of area size and done in much higher volume than an electronics closet. Bob > On Oct 26, 2016, at 1:58 PM, John Ackermann N8UR wrote: > > On 10/26/2016 1:00 PM,

Re: [time-nuts] eLORAN on the air for 30 days

Hi > On Oct 25, 2016, at 7:30 PM, Magnus Danielson > wrote: > > Charles, > > On 10/26/2016 01:10 AM, Charles Steinmetz wrote: >> Magnus wrote: >> >>> It's interesting in that it's clearly not dead yet, rather the opposite. >> >> No, it's well and truly dead. Of

Re: [time-nuts] eLORAN on the air for 30 days

t and when. >> But that said the fact that its on for a month lets me check some >> references. >> Regards >> Paul >> WB8TSL >> >> On Tue, Oct 25, 2016 at 7:33 AM, Bob Camp <kb...@n1k.org> wrote: >> >>> Hi >>> >>>

Re: [time-nuts] eLORAN on the air for 30 days

is neither practical or easy > to deploy. Then again, I'm biased in that regard. > > 26 Jan did some good, and upcoming leap-second comes very timely in that > regard. > > Cheers, > Magnus > > On 10/25/2016 09:53 PM, Bob Camp wrote: >> Hi >> >> Given th

Re: [time-nuts] eLORAN on the air for 30 days

are using the system for various demonstrations >>> to government types. It is indeed Washingtons speed to resolution thats >>> taking the time. >>> So my crystal ball says nothing at all on what and when. >>> But that said the fact that its on for a month lets me

Re: [time-nuts] eLORAN on the air for 30 days

Hi Has there been any indication of just what they eventually will be doing? Is this a never ending series of experiments or do they now have plans to put something more perminanalt on the air? Bob > On Oct 24, 2016, at 3:23 PM, paul swed wrote: > > The Wildwood, NJ

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

sumed there must be > some internal regulation of the DAC supplies -- but it was what my testing > showed." > > On Sat, Oct 22, 2016 at 5:12 PM, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >> The op amp has a PSRR of roughly 90 db at 1 Hz. A

Re: [time-nuts] Has anybody checked this? GPSDO in kit

Hi There is a *long* list of information on that unit over on EEVBlog. Bottom line is that if you get a good one (you may not) it is a *much* better solution than the other one you are looking at. Bob > On Oct 23, 2016, at 9:32 AM, Giuseppe Marullo wrote: > > Thanks to

Re: [time-nuts] Has anybody checked this? GPSDO in kit

Hi You *could* calibrate the nominal frequency a chip very cheaply these days. They may / the may not, who knows. It certainly *is* done that way on very low cost wrist watches. I’d bet that they do and it leaves the factory set within less than 1 ppm. A good generic crystal is still going

Re: [time-nuts] Has anybody checked this? GPSDO in kit

Hi The bigger issue with doing a “home brew” OCXO is getting crystals with known turn temperatures in a reasonable range for the project. Yes, you can build gear to do temperature runs on crystals and sort bags full of them. It’s likely that your whole bag of 5,000 came from the same bar and

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

his question. > > On Saturday, 22 October 2016, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >> There is an *enormous* difference between regulation and it’s impact on >> stability (which is what this drifted off into) and PSRR and it’s impact on >> pha

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

> reference provided by the ocxo? > > On Sat, Oct 22, 2016 at 11:31 AM, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >> The -12 V line is not the reference for the EFC. It *is* one supply into >> the op amp circuit >> that drives the EFC. Since th

Re: [time-nuts] Has anybody checked this? GPSDO in kit

Hi > On Oct 22, 2016, at 10:02 AM, Giuseppe Marullo wrote: > > Hello, > > I know, I know it is not supposed to be high end stuff(timenutted), but I was > looking for a GPS clock and noticed that this could be a cheap GPSDO too: > > http://qrp-labs.com/progrock.html > >

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

.j.sto...@gmail.com> wrote: > > It all depends what the -12V rail is for, some have said it directly > references the EFC dac. I would hope an ocxo would have a better tuning > gain on its efc pin than supply pin but maybe that's not always true. > > On Saturday, 22 October 20

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

one routing and > cables... > > On Friday, 21 October 2016, Bob Camp <kb...@n1k.org> wrote: > >> Hi >> >>> On Oct 21, 2016, at 7:44 PM, Scott Stobbe <scott.j.sto...@gmail.com >> <javascript:;>> wrote: >>> >>> A littl

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

Hi > On Oct 21, 2016, at 7:44 PM, Scott Stobbe wrote: > > A little more data on the 7912. > > The first plot shows the tempCo of the 7912 measured with ambient > temperature swings "7912_TempCo.png". Which is -150 ppm/degC. > > The second plot is off a 7912 logged

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

Hi At least in terms of voltage regulation (as opposed to noise), the -12V input on the TBolt is the *least* sensitive input on the TBolt. It’s issue is only in terms of PSRR. The internals of the unit take care of any drift or really low frequency stuff on the -12 input. Bob > On Oct 21,

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

Hi > On Oct 21, 2016, at 12:20 AM, Scott Stobbe wrote: > > Nick had mention that the -12V rail on the thunderbolt has the poorest PSRR > with respect to frequency output, so I first took a look at the venerable > 7912. > > The first data-set was taken with a -13.5 VDC

Re: [time-nuts] 1PPS to 32.768 khz

Hi One problem with a PLL and a 1 Hz input are the values of components you get in the loop. The other issue is the cost of the VCXO that will get you to 32,768 KHz. The PLL as described by the OP would need the 1 pps divided by 2 with a lot of PLL chips. You now are locking 32768 to 0.5 Hz.

Re: [time-nuts] 1PPS to 32.768 khz

HI That approach would also work fine on a “internal clock” MCU. Scratch the need for a fancy timer. You may be down under 50 cents …. Bob > On Oct 19, 2016, at 7:15 PM, Mark Sims wrote: > > Here's another way to do it for a wall clock display... set up an >

Re: [time-nuts] 1PPS to 32.768 khz

Hi As has been already mentioned, a lot depends on what you have. The drop dead cheapest way to do it: Start with an MCU with an internal oscillator. There are *lots* to pick between. Which sort really does not matter. For example, I’ll use one that starts at 4 MHz. Divide the 4 MHz down to

Re: [time-nuts] HP3325B frequency jitter specification

Hi Are we talking about a stability (a variation from an earlier reading) or about accuracy (a deviation from target) ? Based on your description it’s an accuracy issue. I’d guess that one of the loops in the synthesizer is “stuck” at an offset of 0.003 Hz. Since it is constant, that should

Re: [time-nuts] Phase-noise through mixer?

Hi Simple answer is yes. More complex answer gets into things like the noise of the mixer (not just it’s floor), the levels of the signals, noise being coherent rather than non-coherent, AM <-> PM conversion and on and on …. Bob > On Oct 17, 2016, at 4:45 PM, Anders Wallin

Re: [time-nuts] Moving GPSDO

Hi Survey is pretty much a bad thing while in motion :) Some (but not all) GPS modules allow you to set up in a “mobile / do not survey” mode. This is one area that the newer ( = not 1997 era) devices do much better at. It also is something that SBAS / EGNOS / WAAS may indeed help you out on.

Re: [time-nuts] Moving GPSDO

ILwgQhjC_Q > > He talks about how crystal oscillators are sensitive to movement and changes > in gravity. An interesting watch! > > -Randal > (at CubeCentral) > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@febo.com] On

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