[time-nuts] Lady Heather Ver 4.0 beta test available (has Linux support)

I have uploaded a ZIP file to tinyupload.com with the source and a Windoze .EXE file for the beta test version of Lady Heather. For Windows users, copy the heather.exe to your current Lady Heather directory (might want to first rename or copy your old heather.exe as a backup. For Linux users,

Re: [time-nuts] Advise on building a DIY GPSDO?

Lars wrote: I have wondered what is meant by a proper digital filter below? Is a proper digital filter something more than the LP-filter + PI-loop I use in the DIY Arduino GPSDO? What is used in commercial GPSDOs? The loops are substantially more sophisticated than a simple LP filter --

Re: [time-nuts] Western Electric O-451A/U double-oven XO

Eric The long time constant to deal with the old single phase shift per hour will not help to deal with the 180 degree phase shift per second. Search time-nuts for d-psk-r and wwvb bpsk. That should help you. Regards Paul WB8TSL On Tue, Apr 26, 2016 at 5:02 PM, Eric Scace wrote:

Re: [time-nuts] SE880 GPSDO

I will use a dedicated FPGA design, and the data will be stored into an SDXC card (UHS), or an IDE drive (maybe not), in RAW mode (no filesystem). Each timestamp will be stored into a word of 48bits, the clock will be 400MHz, so the quantization will be 2.5ns, but the maximum error/clock

Re: [time-nuts] SE880 GPSDO

On Tue, 26 Apr 2016 23:39:40 +0200 Ilia Platone wrote: > BTW, the u-Blox NEO-M8N doesn't fit RTK specs (patched it returns RAW > data): it works on band L1 (20cm range), what I need is a GPS module > capable on wiorking on L1+L2 to get 1cm range precision (if it's

Re: [time-nuts] SE880 GPSDO

On Tue, 26 Apr 2016 22:24:08 +0200 Ilia Platone wrote: > I must print each photon event captured by an APD at the focus of more > telescopes, these events must be timestamped with an accuracy of 2.5ns, As i wrote before, 1ns should be doable with standard timing GPS

Re: [time-nuts] SE880 GPSDO

On Wed, 27 Apr 2016 08:25:55 +1200 Bruce Griffiths wrote: > 1) Relative position of any pair of clocks located up to 2km apart has to be > known to within 3cm or so. Post processing is OK, however differential Earth > tides between the clock locations may need to be

Re: [time-nuts] Western Electric O-451A/U double-oven XO

> On 2016 Apr 26, at 16:25 , paul swed wrote: > > Tom, > Thanks for sharing the photos. > > Comments > It looks like most of the items will clean up very well with a bit of TLC. Agree. That won’t be hard. Mostly sawdust from cellar storage at my parents’ home. > Tom

Re: [time-nuts] More graphs: OCXO step, holdover recovery

> What was the reason for holdover? Crappy antenna location. > What puzzles me is the large hump upwards in DACvalue. Anyone knows what is > the reason? My guess is poor filtering on the initial data when coming out of holdover, probably complicated by inadequate testing and/or that case

Re: [time-nuts] Z3801A recovering

Art, Thanks for the link. Very useful information. I also read the 'VP Service note" posted there. Is that note also referring to the oscillator, or some other component that needs periodic recalibration. In any case, it seems that they are recommending that we power down our GPSDO units every

Re: [time-nuts] SE880 GPSDO

Errata.. Il 26/04/2016 22:24, Ilia Platone ha scritto: Hi Attila, This is a hobby project, by now, but if these devices can be versatile and small, they could be used for a work project. till now, hobby and open source. I am stuck at the timing issues. After finding a suitable stable

Re: [time-nuts] SE880 GPSDO

Hi Attila, This is a hobby project, by now, but if these devices can be versatile and small, they could be used for a work project. till now, hobby and open source. I am stuck at the timing issues. After finding a suitable stable clock, on multiple and independent boards, for 8 hours, I'll

Re: [time-nuts] SE880 GPSDO

On Tuesday, April 26, 2016 02:40:14 PM Attila Kinali wrote: > Ciao Ilia, > > On Tue, 26 Apr 2016 02:24:04 +0200 > > Ilia Platone wrote: > > Just for informations, as I must build the board from scratch, does this > > design is good to implement into the datalogger? > > I

Re: [time-nuts] Western Electric O-451A/U double-oven XO

Tom, Thanks for sharing the photos. Comments It looks like most of the items will clean up very well with a bit of TLC. Tom it may be you actually who wrote about the clock and getting it working. Either way I am pretty sure Eric can find helpful details before he applies power. The same goes for

Re: [time-nuts] Western Electric O-451A/U double-oven XO

> Unfortunately I never had any documentation for the O-451A/U unit. > I wonder if anyone else has experience with this oscillator, or has any > documentation. > Since it hasn’t been operating in the last 30 years, I’d like to replace the > electrolytics > capacitors — but this would be much

Re: [time-nuts] Advise on building a DIY GPSDO?

Hello Charles and others I have wondered what is meant by a proper digital filter below? Now I was reminded by the KS-24361 holdover graphs from Hal. Is a proper digital filter something more than the LP-filter + PI-loop I use in the DIY Arduino GPSDO? What is used in commercial GPSDO´s? I am

[time-nuts] Western Electric O-451A/U double-oven XO

Hi — I have finally retrieved from my parents’ home my original time & frequency standards lab, to which will be added my more recent HP Z3805A. The assembly contains: HP-113BR frequency divider/clock homebrew WWVB receiver & frequency comparator, with its own internal OCXO standard, that

Re: [time-nuts] More graphs: OCXO step, holdover recovery

Thanks for the graphs. Interesting to see the recovery from holdover on the KS-24361. What was the reason for holdover? What puzzles me is the large hump upwards in DACvalue. Anyone knows what is the reason? Could it be that the loop changes time constant? Even after the second holdover a

[time-nuts] Dead tree material: Ships, Clocks, and Stars: The Quest for Longitude

I usually don't have very much to contribute to this list, a lot of what gets discussed here is a bit above my pay grade, so I mostly just read and hope some of it sinks in. Also not sure how much interest there is on this list in dead tree material. That being said, I was at Ollie's Bargain

Re: [time-nuts] Z3801A recovering

Joe, There is a "VP Oncore Startup" note here that's worth a try: http://www.synergy-gps.com/index.php?option=com_content=view=42=89 Please note that if the above link expands to more than one line after it leaves our server it is due to our use of MS SafeLinks app in Outlook. If the link is

Re: [time-nuts] Z3801A recovering

Now that I finally have some replacement Oncore VP modules, I've been able to do some tests and comparisons. Using WinOncore 12, I tested the VP's that I got from Pete. Then I compared the old module from the Z3801A. The old module seems to be deaf. It reports that it sees plenty of satellites,

Re: [time-nuts] SE880 GPSDO

Insufficient information to indicate if carrier phase data is externally available.Without this it appears that the position accuracy is around 10x worse than the requirement for 10ns timestamp accuracy. The timing stability is also somewhat unknown.How well will 2 independent modules track

Re: [time-nuts] SE880 GPSDO

Ciao Ilia, On Tue, 26 Apr 2016 02:24:04 +0200 Ilia Platone wrote: > Just for informations, as I must build the board from scratch, does this > design is good to implement into the datalogger? > I mean, for the second RTK purpose, does this u-blox module satisfy my >

Re: [time-nuts] SE880 GPSDO

:) yes, it is. Basically I need to sync two signals at a variable frequency centered at about 10MHz, for 8 hours. The actual bandwidth depends because there will be a variable number of harmonics on such signal. The data logging system is for the intensity interferometer, and it needs an

Re: [time-nuts] SE880 GPSDO

Thank you Attila, Just for informations, as I must build the board from scratch, does this design is good to implement into the datalogger? I mean, for the second RTK purpose, does this u-blox module satisfy my requirements (link below)? http://www.opendigitalradio.org/lea-m8f-gpsdo Regards,

Re: [time-nuts] SE880 GPSDO

Thanks Bruce, I know this, the delays due to the light path difference will be calculated later by software, and i can have filters with a bandwidth of 3-5 nm, two 0.4m diameter telescopes. the distance of the two telescopes will be around 2500m and the maximum delay between these two signals

Re: [time-nuts] More graphs: OCXO step, holdover recovery

Hi The 5334B event is commonly called a frequency jump. There is a fairly famous HP paper on testing for them that invokes the phrase “test to destruction” (if I remember correctly). They are seen in all OCXO’s if you watch enough parts long enough. They tend to increase in time between jumps

Re: [time-nuts] SE880 GPSDO

Hi Well, based on about a hundred breadboards, it always comes out this way regardless of who does the layout or what caps are used for a buffer amp. Consider that this is *not* an oscillator, so the only cap that is sure to be there is a blocking cap. Bob > On Apr 26, 2016, at 5:22 AM,

[time-nuts] More graphs: OCXO step, holdover recovery

An interesting step in the OCXO http://users.megapathdsl.net/~hmurray/time-nuts/HP-5334B-step-2016-Apr-23.pn g This is a from second HP5334B that has been running for months so the offset will be different. This is KS-24361 recovering from two holdover events of 12 or 13 minutes each:

Re: [time-nuts] SE880 GPSDO

On Mon, 25 Apr 2016 20:45:53 -0400 Bob Camp wrote: > > To get to CMOS levels, you usually add a simple inverter, with an > > capacitor in front and a 1M resistor across the inverter (from input > > to output). > > If you set up a modern (74AC or faster) inverter with a resistor