Re: [time-nuts] Racal 9475 Rubidium

> On May 2, 2018, at 7:13 PM, Roger Tilsley wrote: > > > > In my experience, FRK modules produce their best performance when operated > from a supply voltage between 27 V and 28 V, selected for individual units > but 27.6 V is a good starting figure. Would there

Re: [time-nuts] Setting correct date on Trimble Thunderbolt receiver

In general, I believe whether you can work around the 1024 week problem and if so, how, tends to be a receiver-by-receiver thing (or at least manufacturer-by-manufacturer). I’m most familiar with the SkyTraq Venus838, and those have a sliding window system where you set a “reference date” and

Re: [time-nuts] ECS ECOC-2522 (was GPS Talking Clock)

. > On Feb 18, 2018, at 7:54 AM, Nick Sayer via time-nuts <time-nuts@febo.com> > wrote: > > No they don’t. I wrote and asked them and they sent me back some sample data. > They were a pretty pleasant surprise. > > > >> On Feb 18, 2018, at 6:04 AM, Bob kb

Re: [time-nuts] Need a Watch Recommendation

Lots of folks have chimed in on this thread, but I will just add that the Apple watch is an NTP client. I’m extremely happy with mine, but the reasons I am are far, far wider than its accuracy (which I can only judge by eye, which is an extraordinary low bar for a Time Nut). > On Mar 4, 2018,

[time-nuts] GPS Talking Clock

It’s been a while since I’ve posted here, but I’ve had a bunch of irons in the fire. I’m working on adapting my GPSDO to the ECS ECOC-2522, which the manufacturer claims has a short term ADEV in the low -12s, but I haven’t gotten it doing that well yet. But one thing that is ready (well,

Re: [time-nuts] Designing an embedded precision GPS time

At the moment, my plan is to not support hold-over at all. If GPS doesn’t have a fix and I’m not getting PPS pulses, I intend to either jump immediately to stratum 16 or just not respond. > On Oct 31, 2017, at 1:03 PM, Attila Kinali wrote: > > Hoi Leo, > > On Sat, 28 Oct

Re: [time-nuts] Designing an embedded precision GPS time server

I think my test rig is likely to be a pair of units connected with a crossover cable, with test firmware on one to act as a fake client, and using spare GPIOs on test points to measure latency and the like with a scope. I don’t have the wherewithal to try and gauge the timing of switches, and

Re: [time-nuts] Designing an embedded precision GPS time server

That looks and sounds very, very much like what I want to do. Thank you very much for your testing suggestions. When it comes time, I had indeed planned on adding it to the NTP pool if for no other reason than to contribute to the cause (but also for testing). I believe I’m going to start with

[time-nuts] Designing an embedded precision GPS time server

I’ve just completed a project (off topic) with the ATSAMS70 chip and learned a lot in a relatively short time, and I really like the result. I am considering a new project based on its cousin, the ATSAME70. The E70 has an Ethernet 10/100 MAC built in as well as the rest of the stuff the S70 has

Re: [time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?

FWIW, I’ve documented the whole R-Pi GPS NTP thing at https://hackaday.io/project/15137 As a disclaimer I will also say that I’m not even remotely the first. But what’s kind of nice is that I have a R-Pi desk clock display board that plays really well with a bolt-on GPS cap. In fact, I’ve got

Re: [time-nuts] Fw: Skytraq / GPS Almanac

I don’t have any SkyTraq navigation modules, but I power cycled a couple of my clocks (with the timing modules) and they came back up as they usually do, so I can tentatively confirm that in survey-and-hold mode they don’t appear to have any problems getting a fix. TBD is vetting the results to

[time-nuts] Book review: "How We Got To Now."

I happened to be at Powell's bookstore in Portland the day after the eclipse and came across this book and wound up buying it. It's attraction to me was the same that I felt growing up watching the documentaries hosted by James Burke - Connections and The Day The Universe Changed. Both Burke

Re: [time-nuts] Trimble Thunderbolt no longer determines thecorrect date

FWIW, the SkyTraq receivers have the notion of a “UTC reference date” which allows the 1024 week window to roll forward indefinitely as long as you update that value once in a while. I’ve written code in my GPS Clock to update the reference date once a year as well as update the default GPS-UTC

Re: [time-nuts] GPS seconds conversion on an Arduino

The GPS-UTC delta is part of the set of data GPS sends down from the satellites. My GPS clocks will show the time two seconds fast for some amount of time ranging from 0 to 12 minutes after first-fix because the periodicity of that particular message is 12 minutes. My guess is that 2 seconds

Re: [time-nuts] GPS seconds conversion on an Arduino

I wouldn’t expect floating point to enter into it. Add the leap second correction in, then take seconds modulo 86400 and you get the second-within-the-day. Divide seconds by 86400 and you get the day number. With the day number, it’s quite straightforward to figure out gregorian date given a 0

Re: [time-nuts] A good GPS-Receiver with 1PPS output...

I use it in all 3 of my GPSDO designs and it works pretty much ideally so far as I can tell. > On May 12, 2017, at 9:56 AM, Bryan _ wrote: > > How well would the Venus work as a receiver for a GPSDO project using the > 1pps output? > > > -=Bryan=- >

[time-nuts] Raspberry Pi Sidereal clock display

A while ago, I took my GPS clock board (https://hackaday.io/project/18501-gps-clock) and sort of rearranged it to instead be a Raspberry Pi Zero clock display. I turned it into a product on Tindie for folks who can more easily get NTP over WiFi or Ethernet than GPS. Recently, someone asked me

[time-nuts] Bay Area Maker Faire '17

Anybody else going to Bay Area Maker Faire next weekend? I’ll have a booth there (heavy on clocks and GPS) and would love to meet anyone going. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] A good GPS-Receiver with 1PPS output...

https://www.tindie.com/products/nsayer/skytraq-venus838lpx-t-timing-gps-module-breakout/ > On May 11, 2017, at 5:36 PM, djl wrote: > > Can't find this on Tindie??? > > On 2017-05-10

Re: [time-nuts] WTB: GPSDO

The splitters I’m using do have a 200Ω load on them. I know this because PA6H modules recognize an external antenna and use it. > On Mar 22, 2017, at 3:20 PM, Chris Caudle <ch...@chriscaudle.org> wrote: > > On Wed, March 22, 2017 3:52 pm, Nick Sayer via time-nuts wrote: &g

Re: [time-nuts] WTB: GPSDO

> On Mar 22, 2017, at 12:40 AM, Thomas Petig wrote: > > > The special GNSS splitters forward DC only from one port and provide > some 200 Ohm DC termination together with the DC-block on the other > ports to keep the receiver happy, i.e., it seems current consumption and >

Re: [time-nuts] Best Chance GPS module

n the >> top floor of a two-storey building, with just the power fed to it, watching >> the LED flash. >> >> Maybe I was unlucky? I wonder what experience others have? > > From: Nick Sayer via time-nuts > > Was the LED on the PPS pin or on the FIX pin? >

Re: [time-nuts] Best Chance GPS module

Was the LED on the PPS pin or on the FIX pin? The FIX pin is nothing like the PPS output. Frankly, I’m not 100% sure what the rules are for it. When things are working properly, it blinks at 0.5 Hz, but the leading and trailing edges are something like 120-150 msec after the second. It’s very,

Re: [time-nuts] Smart Phone time display accuracy...?

The time on mine is quite good, but I believe that’s because I have an Apple watch. If you pair an iOS device to an Apple Watch, I believe it suddenly “tries much harder” to keep its own clock in sync so that it can serve good time sync to the watch. Apple has made grandiose claims about the

[time-nuts] New project: Raspberry Pi Zero W NTP clock

I’ve made a variation on my GPS clock that uses the new Pi Zero W (in truth, it could use an ordinary Pi Zero with some other network connectivity. The W’s built-in WiFi just simplifies things a bit) to drive the same LED display. The local time would ostensibly be synced by NTP in the usual

Re: [time-nuts] OT: Eagle PC CAD now Autodesk, $500/year

I think the alternative with the greatest momentum at the moment is KiCAD. I haven’t tried KiCAD yet. The problem I have is that I have a ton of libraries and projects I’d have to convert. I suspect that there is automation to perform the import (or soon will be), but it’s basically NRE that

Re: [time-nuts] New stuff in my Tindie store

> On Dec 26, 2016, at 7:40 PM, Nick Sayer via time-nuts <time-nuts@febo.com> > wrote: > > > The second one will be up next week, and it’s a simple GPS clock. The listing for the clock is live now: https://www.tindie.com/prod

Re: [time-nuts] A Leap Second is coming

Here's what I got: https://youtu.be/nGMFzhNFrb4 It worked as I expected. 4:00:00 PM was two seconds long. Sent from my iPhone > On Dec 30, 2016, at 11:49 AM, Nick Sayer via time-nuts <time-nuts@febo.com> > wrote: > > I'm going to definitely observe my GPS clock to

Re: [time-nuts] A Leap Second is coming

I'm going to definitely observe my GPS clock to check its behavior. It *should* repeat second zero (in my case of 4PM PST). Not the most exactingly accurate depiction, but it's the best I can do with the architecture. Sent from my iPhone > On Dec 29, 2016, at 12:22 AM, David J Taylor

Re: [time-nuts] New stuff in my Tindie store

> On Dec 26, 2016, at 9:22 PM, Mark Sims wrote: > > Ahhh, the subtle wonders of time zones and DST changes... Heather lets you > set your time zone offset down to the second, and does not range limit the > offset. If you want UTC +987:65:43 it's yours! There are a

Re: [time-nuts] New stuff in my Tindie store

I thought of a WiFi+NTP variant, but I haven’t played with the various ESP WiFi modules that are in vogue for Arduino and the like. From what I know about those, it’d probably be easiest to ditch the board’s ATTiny841 and just add support for the bit-banged SPI display controller directly

Re: [time-nuts] New stuff in my Tindie store

& Asia went to G.M.T. +13 as its > timezone a few years back. > > Cheers, > Will > > On 12/27/2016 04:40 PM, Nick Sayer via time-nuts wrote: >> I’ve finally added the power supply I’ve designed for the Thunderbolt. It’s >> a combined switching+linear design. It’s

[time-nuts] New stuff in my Tindie store

I’ve finally added the power supply I’ve designed for the Thunderbolt. It’s a combined switching+linear design. It’s been running my own Thunderbolt for a while now. There’s a schematic on the store page and it can come with or without a 15W primary supply.

Re: [time-nuts] Best replacement for Trimble Bullet antenna

tart. One dissolves in water, the other > has no structural integrity. Nylon is hydroscopic > and not all that great at 1.5 GHz. For what ever reason the polycarbonate > that they sell also is a bit hydroscopic. It also is > quite challenging to print unless you have a very fancy printer.

Re: [time-nuts] Best replacement for Trimble Bullet antenna

> On Nov 22, 2016, at 9:39 PM, Dennis Lloyd wrote: > > Your problem will be Birds and Debris, it is flat and you will have > interruptions and phase shifts. > > Did you not understand why we use pointed antennas for timing and fixed > installations. No, I guess I

Re: [time-nuts] Best replacement for Trimble Bullet antenna

I bought a Gilsson marine antenna and an 8 port amplified splitter on eBay. The antenna is mounted on the roof of my garage, where it has visibility easily down to 20 degrees except to the North where there is an obstruction (but that doesn’t matter). The coax is 10 meters of whatever came with

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

I’m going to try and describe my thoughts, but it may not come out as “right” as some others here can do. Still… One problem you’re going to run into if you go down the road of attempting to PLL one thing to another is that you have to find a balance between phase control and frequency

Re: [time-nuts] WWV receivers?

ay the > quality of that crystal is a not a big deal. > > On Fri, Oct 28, 2016 at 10:36 PM, Nick Sayer via time-nuts > <time-nuts@febo.com <mailto:time-nuts@febo.com>> wrote: > That single-chip version is going to have a *LOT* less (and less variable) > latency than an

Re: [time-nuts] WWV receivers?

That single-chip version is going to have a *LOT* less (and less variable) latency than an SDR. > On Oct 27, 2016, at 12:20 AM, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > > In message <5a002554-8d90-4c75-95da-21db45d61...@kfu.com>, Nick Sayer vi

Re: [time-nuts] WWV receivers?

If you’re in North America, a CHU receiver is a lot easier to make than WWV/WWVH. The CHU timecode is just BEL 103 AFSK at 300 baud - it was a one-chip solution 20 years ago when I made one in college. On the software side, you’ll want a serial line discipline kernel module of some sort that

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

tobbe < >>>>>> scott.j.sto...@gmail.com <mailto:scott.j.sto...@gmail.com> >>>>>> <javascript:;> <javascript:;> >>>>>>>> <javascript:;>> >>>>>>>>> wrote: >>>>>>

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

Well, because it's easily an order of magnitude more expensive than a 7912. $5 instead of 50¢ (Q:1). If it *matters*, then fine, but I am sensitive to cost efficiency in addition to efficacy. If you put the board in a box in a stable temperature environment (which I'd kind of assume you'd do

Re: [time-nuts] KSC big clock

This may be obvious, but anyone making such a device today would be well advised to use LED strips instead. We just upgraded the lighting in my wife’s office/craft room with an LED panel light. It’s around 4’x1’x1” and puts out 4000 lumens - quite bright and enough to fill the entire room with

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

Just an update. I’ve built the second prototype board (I skipped over the first design), and it’s powering my tbolt right now. The design calls for 15v in (though it would also work with 13.8v). The +12 output comes from a D2PAK 7812. For +5, there is an AP1509 buck converter to make around

Re: [time-nuts] Atomic Watch

"Whereas other clocks fall victim to relativistic effects at high speeds, cesium clocks do not. The frequency remains the same, and so the time remains accurate.” Well, to the wearer, it probably does. :) It’s ironic they said that given that they flew cesium clocks in the Hafele–Keating

Re: [time-nuts] Moving GPSDO

Speaking for my GPSDOs specifically, you can’t disable the survey mode with the Venus838 receiver (well, you can, but it requires you to talk to the module with SkyTraq’s software, which requires disabling the GPSDO’s controller - possible to do, but annoying). I haven’t attempted to see what

Re: [time-nuts] For those that insist on using switching power supplies

b-apple-is.html ) > > Cheers! > > -Randal R. > (at CubeCentral) > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Nick Sayer > via time-nuts > Sent: Friday, 14 October, 2016 12:17 > To: Discussion of precise tim

Re: [time-nuts] For those that insist on using switching power supplies

Set your scope for AC coupling. Set your scope probe for 1x rather than 10x. Use the absolutely shortest scope grounding you can. That’s what those spring looking things that came with it are for. I typically use the spring gizmo and probe on an SMD cap. The ground wire with an alligator clip

Re: [time-nuts] For those that insist on using switching power supplies

> On Oct 13, 2016, at 6:05 AM, Van Horn, David > wrote: > > To be fair here, phone chargers have almost no requirement to be quiet other > than conducted and radiated emissions limits. > It’s charging a battery. Not quite. They power the device in

Re: [time-nuts] New PPB rated TCXO

The video linked on that page is particularly interesting (if you take it on face value that they're not faking it. ;) ). Sent from my iPhone > On Oct 10, 2016, at 8:03 AM, Robert LaJeunesse wrote: > > For general group information, as SiTime datasheet is not open to the

Re: [time-nuts] Venus838LPx-T PPS stability measurements

As a control, I repeated the test with a GlobalTop PA6H module. Again, the reference is a Thunderbolt, so it’s not completely clear how much of the wander to attribute to the reference and how much to the DUT. The residual this time is on the order of 60ns - still surprisingly high. The DUT is

Re: [time-nuts] Venus838LPx-T PPS stability measurements

Buh… No graphs? Um… “I’m a little teapot, short and stout…” :) I’ll link it here instead: http://www.kfu.com/~nsayer/Venus838LPx-T_graphs.zip > On Oct 7, 2016, at 7:46 AM, Nick Sayer via time-nuts <time-nuts@febo.com> > wrote: > > This is a bit overdue, but I finally go

[time-nuts] Venus838LPx-T PPS stability measurements

This is a bit overdue, but I finally got around to making at least an attempt to measure the stability of the Venus838LPx-T timing module’s PPS stability. The results are a bit of a mixed bag. The module under test is one built into one of my OH300 GPSDOs. It’s inside of a closed chassis,

Re: [time-nuts] Need Time Help

To be fair, this is at least partly because asking a relatively simple question here routinely turns into a dissertation defense. > On Oct 6, 2016, at 3:45 AM, Bob Camp wrote: > > Hi > > That’s very typical in a lot of forums. The OP tosses up a question and then > pretty much

Re: [time-nuts] ADC sample voting algorithm?

> On Oct 5, 2016, at 5:00 PM, Bob Camp wrote: > > Hi > > What does the signal you are sampling look like? The last time I actually looked (it was a while ago), it looked reasonable as closely as I could look, but the ADC resolution is something like 1mV per LSB, and I’m not

Re: [time-nuts] ADC sample voting algorithm?

he ADC values because of their stability “most” of the time (meanwhile, the uncorrected values are bouncing around inside a 12 ns corridor). > If not, are you merely seeing a hanging bridge that dissolves into at a > normal sort of tick-tock movement? > > Bob > > From: Nick

[time-nuts] ADC sample voting algorithm?

This is tangentially on topic, I suppose. It’s for my GPSDO. I notice periodically that the phase measurements seem “noisy.” You can see that over the course of several seconds the value doesn’t change, then it jumps a bunch and then comes right back. My theory at the moment is that sampling

[time-nuts] Lady Heather on MacOS X

Sorry if this is old hat, but I don’t remember seeing it go by. I just went through the exercise of getting Lady Heather working on MacOS X. It’s not a Quartz port - you have to install and run XQuartz for it to work. One patch to heather.ch was needed: Right below the include of fcntl.h:

Re: [time-nuts] Schematic needed

I don’t know about that particular one, but I designed an equivalent board and was selling it on Tindie a little while ago. I replaced it with a full-on GPS discipline board that powers and trims the 5680 from GPS. But if all you want is the power part of it, I still have the design for the

Re: [time-nuts] A new take on the all-hardware GPSDO concept

At the risk of inviting everyone to say “I told you so,” I’ll report here my experimental results from trying this concept out. Since there was a great deal of doubt about the outcome, I hedged my bet a bit and designed for the DOT050V rather than the OH300. If it worked out for the TCXO, then

Re: [time-nuts] A new take on the all-hardware GPSDO concept

> On Sep 16, 2016, at 1:13 PM, Lars Walenius wrote: > > > > My experience with the Venus838-T is only 2 weeks but disappointing. This can > also be guessed from the datasheet ADEV curve, that I guess is sawtooth > corrected values as it starts at 3E-9 at 1s, but

Re: [time-nuts] A new take on the all-hardware GPSDO concept

> On Sep 12, 2016, at 1:27 PM, Charles Steinmetz wrote: > > Tim wrote: > >> You know Nick, the loop time constant typically used with the HMC1031 loop >> filter is typically 5 milliseconds. I'm sure some bigger R's and C's can >> used for a longer time constant, and I'm

Re: [time-nuts] A new take on the all-hardware GPSDO concept

0.01 to 10 Hz than the GPS. I don’t see where you get that. To generate the phase noise figures (8,9,11,12) they used a Crystek CVHD-950. I don’t think it necessarily follows that a better quality OCXO can’t do better than that, does it? > > Bob > > >> On Sep 12, 2016, at

[time-nuts] A new take on the all-hardware GPSDO concept

I was talking with someone at AD about a question I had about one of their TinyDACs when they mentioned their HMC1031 chip. It looks like the ideal building block for a clean-up oscillator. It struck me just a touch later that the Venus838LPx-T has by default a 10 MHz output that’s phase

[time-nuts] ke5fx.com - something's up

I tried to look for Lady Heather docs today, but it appears like the ke5fx domain is… funky. The name servers are NS1.PENDINGRENEWALDELETION.COM and there are other indications that maybe the domain lapsed…? ___ time-nuts mailing list --

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

When I began the design process, I assumed - as would be reasonable - that ~30 mV P-P of noise and ripple were acceptable for input power supplies, and that before they were used for a precision purpose within the device that there would be further filtering if for no other reason that you’d

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

> On Aug 30, 2016, at 9:26 PM, Mark Sims wrote: > > The -12V is used to drive the RS-232 signals... it also eventually gets to > the EFC dac so it can swing below ground. Also, the +12V gets to the DAC. > Pay close attention to generating noise on these lines. I’ve

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

A little board to generate -12 and +5 from a 15 watt 12 VDC input wouldn’t be too hard to design. If I put one out for $25, would anyone like one? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

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

odules are a > bit worse than newer ones. Also sawtooth correction can make things a bit > better. > > Bob > > Sent from my iPad > >> On Aug 17, 2016, at 2:51 PM, Nick Sayer via time-nuts <time-nuts@febo.com> >> wrote: >> >> Updating the EFC

Re: [time-nuts] Venus838LPx-T preliminary testing

I had an opportunity to examine the P1PS2 pin’s output from the Venus838LPx-T. By default it’s a 10 MHz output nominally phase locked to GPS time. It didn’t take more than a second of looking at it on the scope to discover that it’s jittery as hell. My guess is that they’re synchronizing its

Re: [time-nuts] Heathkit clock available

> On Aug 10, 2016, at 4:01 PM, David <davidwh...@gmail.com> wrote: > > On Wed, 10 Aug 2016 16:55:39 -0400, you wrote: > >> On 8/10/2016 11:31 AM, Nick Sayer via time-nuts wrote: >>> Frankly, I don’t know why they didn’t make it a GPS clock. That would truly &g

Re: [time-nuts] Heathkit clock available

Frankly, I don’t know why they didn’t make it a GPS clock. That would truly be a worthy successor to the GC-1000. Well, I do suspect I know why… and it’s not flattering. :) Heck, if I thought I’d sell more than a handful, I’d make a desk-side GPS alarm clock and put it on Tindie. I’m actually

Re: [time-nuts] Venus838LPx-T preliminary testing

I don’t know if I’d go that far. It’s more than conceivable that the 822A runs the same firmware as the 838 and therefore the actual functionality quoted in the datasheet is met. Frankly, that’s the high order bit here - not what the label on the chip says, but whether it performs the way the

Re: [time-nuts] Venus838LPx-T preliminary testing

And with that, the first run is out of stock. But don’t worry, I’ve placed an order for more modules and boards. Should be back in stock within a couple weeks, and the stock will run quite a bit deeper than the first batch did. > On Aug 9, 2016, at 10:15 AM, Mark Sims

Re: [time-nuts] Venus838LPx-T preliminary testing

If you're talking about the NS-T, the picture on their store suggests it may not be the exact same module. Their picture shows a Venus822A. That doesn't necessarily imply that it doesn't have the same behavior, of course. Sent from my iPhone > On Aug 8, 2016, at 9:53 PM, Mark Sims

Re: [time-nuts] Venus838LPx-T preliminary testing

> On Aug 8, 2016, at 7:26 PM, Clay Autery wrote: > > Wow... fast turn-around... > > I might grab one of these for my NTP project for my home network... > > Reckon they’d integrate with the Rasberry-Pi and other similar? Absolutely. In fact, the prototype has replaced the

Re: [time-nuts] Venus838LPx-T preliminary testing

> On Aug 5, 2016, at 8:13 PM, Nick Sayer via time-nuts <time-nuts@febo.com> > wrote: > > > I’m going to make a breakout board for these and list them on Tindie next > week, for those who wish to play with them. As promised, the breakout boards are now available.

[time-nuts] Heathkit clock available

I just got an email announcing this: https://shop.heathkit.com/shop/product/most-reliable-clock-tm-gc-1006-26 They bill it as a "most reliable" clock. From the description it appears to be an AC line disciplined clock with battery backup. I only mention it here because of the periodic

[time-nuts] Venus838LPx-T preliminary testing

I got the first breakout boards back today. There’s an error on them I had to workaround, but having done that I was able to observe it getting first-fix (with good reception, TTFF is remarkably good, FWIW), then performing the 2000 point survey and generating quantization error messages. I’ve

[time-nuts] Best choice for GPS active antenna voltage?

In designing boards with the Venus838LPx-T module, I must supply external antenna power myself. This is in contrast to the PA6H I’ve been using which internally supplies 3.3v active antenna power (and measures it for loading to switch between the internal and external antenna. The Venue module

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

> On Aug 1, 2016, at 9:33 AM, Chris Albertson wrote: > > > > In fact that would be a good experiment: Put two clocks up on a large > computer monitor and make one always tick some random number of > milliseconds away from system time and the other always thick on

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

I’ve used the PA6H so far for all of my GPSDOs. The two reasons I am considering the Venus838LPx-T to replace it are that it has a sawtooth correction message and it has a survey and static solution mode to allow it to tolerate poorer reception. I’m driven to want to experiment with a static

Re: [time-nuts] Venus838LPx-T opinions?

The NMEA STI,00 message gives a sawtooth correction. I believe what Mark was saying was that there was no *binary* message that said so… maybe? I dunno. But the datasheet clearly talks about PPS quantization error compensation: STI,00 – 1 PPS timing report An output message, id 0x0, contains

Re: [time-nuts] Venus838LPx-T opinions?

to the ATMega328PB to get enough flash space to add the sawtooth compensation handling stuff. But even if I completely ignore the NMEA output of the module, it'll be worth it to get timing firmware with survey capabilities. I'm quite excited. Sent from my iPhone > On Jul 22, 2016, at 3:21 PM, Nick Sayer

[time-nuts] Venus838LPx-T opinions?

Anybody played with one of these? http://www.skytraq.com.tw/products/products-Timing%20Module.html It looks promising for GPSDO designers. It has a survey mode (looks to be automatic) and one of the NMEA messages reports quantization error. The downsides I’ve identified so far are that it’s an

Re: [time-nuts] NCOCXO anyone?

confirmed with the PicoPak project: > > http://www.wriley.com/PicoPak%20App%20Notes%20Links.htm > > So, yes, please take the bait and play with all aspects of your NCOCXO idea. > > /tvb > > - Original Message - > From: "Nick Sayer via time-nuts"

[time-nuts] NCOCXO anyone?

Would anyone see any value in a board that had an OH300 with a serial interface for tuning? I had a thought perhaps to make one starting with my GPSDO and just ditching the GPS part and possibly adding an RS-232 level converter. I could conceivably bring it all out to a DB9 and emulate an

Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year

> On Jul 20, 2016, at 12:25 AM, Tom Van Baak wrote: > > Hi Gary, > >> 2.1 A positive or negative leap-second should be the last second of a UTC >> month, >> but first preference should be given to the end of December and June, >> and second preference to the end of March

Re: [time-nuts] How does sawtooth compensation work?

yer via time-nuts <time-nuts@febo.com> > wrote: > > >> On Jul 18, 2016, at 3:55 PM, Hal Murray <hmur...@megapathdsl.net> wrote: >> >>> The systems gravitate towards PLL time constants that average it all away. >> >> You are overlooking hangi

Re: [time-nuts] How does sawtooth compensation work?

> On Jul 18, 2016, at 3:55 PM, Hal Murray wrote: > >> The systems gravitate towards PLL time constants that average it all away. > > You are overlooking hanging bridges. Yes, that’s true. Given the facilities I have available with the present hardware, I don’t

Re: [time-nuts] How does sawtooth compensation work?

> On Jul 18, 2016, at 4:20 PM, Bob Camp wrote: > > On a receiver with sawtooth correction, you have a manufacturer specific > message that gives > you information on the state of the receiver. It is defined as either > applying to the next pps > or to the pps that just came

[time-nuts] How does sawtooth compensation work?

I've read Tom's page about sawtooth PPS jitter and I believe I understand where it comes from.My current GPSDOs ignore the phenomenon. Certainly at the moment, I'm satisfied with that. The systems gravitate towards PLL time constants that average it all away. What I'd like to understand

Re: [time-nuts] GPS for Nixie Clock

A visual clock has uses other than to be readable by humans. I made a GPS clock once with 100 ms display resolution once for the purpose of timestamping photographs accurately. Photographs can have far, far shorter shutter speeds (or the digital equivalent) than human POV flicker rates. > On

Re: [time-nuts] GPS disciplined Mars clock

I’ve often wondered how much sense it makes to speak of the rotational period of a gaseous planet. The different layers of the atmosphere potentially can have different rotational periods, and we can’t observe the actually rocky (or diamond, if you believe Arthur C. Clark) body at the center.

Re: [time-nuts] Divide by 3

https://www.digikey.com/product-detail/en/on-semiconductor/MC74VHC1G86DTT1G/MC74VHC1G86DTT1GOSCT-ND/2705092 https://www.digikey.com/product-detail/en/nxp-semiconductors/74HC74D,653/568-1490-1-ND/763395 > On Jul 6, 2016, at 8:39 PM, Charles Steinmetz wrote: > > Nick

Re: [time-nuts] Divide by 3

> On Jun 8, 2016, at 9:59 AM, Charles Steinmetz wrote: > > Nick wrote: > >> I’m contemplating trying my GPS board with an FE-405B. That’s a different >> kettle of fish, but at the end of that, if I’m successful, one of the goals >> would be to be able to use it for the

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

> > For more precise stuff timing, I have a Thunderbolt and other goodies. > (Speaking of which, I really need to figure out how to use the > Thunderbolt as an external clock source for my Arduinos.) > I don’t think you can do it for an Arduino without hardware changes. The CLKI pin is shared

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

> On Jun 27, 2016, at 1:34 PM, Nick Sayer wrote: > > > In the firmware, the timer that has the input capture ability is set to > free-run at the system clock frequency. The ICP interrupt reports back the > timer delta from the last interrupt. Nominally, you’d expect 16,384

Re: [time-nuts] How to properly characterize 32kHz oscillators manually and with a microcontroller?

I went through this exercise some time ago with my Crazy Clock. The Crazy Clock is itself an ATTiny45 clocked with a 32 kHz crystal. I desired to determine the accuracy of the oscillator. I wound up making a purpose-built frequency counter. First, the device under test gets special firmware

Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping

> On Jun 23, 2016, at 6:28 PM, Jay Grizzard > wrote: > > On Thu, Jun 23, 2016 at 11:28:00PM +, Mark Sims wrote: >> A usable re-flow oven can be had for $300. > > Do you (or anyone) have suggestions for usable reflow ovens in this price > range? I sell a

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