[time-nuts] London meet-up

Following the thread on EEVblog, I volunteered to organise a London *Nuts meet-up. See here: http://www.eevblog.com/forum/metrology/volt-nut-meetings-and-gatherings/ http://www.meetup.com/London-Nuts-Volt-Time-Metrology/ Regards, Alan ___ time-nuts m

[time-nuts] quartz thermometers

Hi, I hope this is still relevant and not too off-topic...but since it involves crystals and tempco... Quartz thermometers (e.g. the HP 2804A) with their 'linear cut' crystals and '0.0001C resolution' seem to have been a thing from the mid-60's to the mid-80's: http://www.hparchive.com/Journa

Re: [time-nuts] SR620 testing

>>> XY outputs - text at the top is slanted and text near the middle right is >>> overlaid. I don't know if I care about this, as I am unlikely to use this >>> feature. I tried this briefly on a digital scope and it looked a bit iffy. Maybe it's better on an analogue scope. If I remember r

[time-nuts] Cheap GPSDO's

>>> For more money, yixunhk has some nicely packaged units and AFAIK he has a >>> good reputation. BTW I have a '58503A' from him. It did and does (a year later) still work, although it took me a while to get it going. But it was a bit iffy - obviously in a re-made case and the eBay images were

Re: [time-nuts] low noise multiplication to 100 MHz

Do any of the SiLabs 'low jitter' synthesiser / clock generators / jitter attenuators etc help? Alan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructio

[time-nuts] Kode/Odetics 3100 TIA

There's one of these on eBay going cheap: http://www.ebay.com/itm/Kode-Odetics-3100-Time-Interval-Analyzer-Time-Control-Unit-/141858269162? Some observations on it here https://www.febo.com/pipermail/time-nuts/2015-July/092993.html Regards, Alan ___ t

Re: [time-nuts] HP Panel colors

Ah FYI industrial paint and powder coating colours are usually specified as RAL numbers, US sometimes uses FS-595: http://www.ralcolor.com/ http://www.federalstandardcolor.com/ http://www.e-paint.co.uk/search_colour.asp Having said that, the HP names you listed don't seem to match any of these

[time-nuts] 58503A stats

Hi, Here is a screen capture from excellent Ulrich's Z38XX program: https://www.dropbox.com/s/6p5dr8apsftrckf/Z38XX-1.JPG?dl=0 This is the first time that I've seen this output and I have a couple of questions. I should explain that the antenna is fairly well situated in London UK with a good

Re: [time-nuts] 58503A stats

p.s. here's the view south taken from about 2m below the antenna: https://www.dropbox.com/s/zejod2sfi4iogq1/IMG_460371644.JPG?dl=0 Alan From: Alan Ambrose Sent: 04 August 2015 9:50 AM To: 'time-nuts@febo.com' Subject: 58503A stats Hi, Here is a screen capture from excellent

Re: [time-nuts] ground plane for cheap helix antennas?

Hi Attila, Bob et al >>> Generally speaking, you do want satellites as low on the horizon as >>> possible, because they give you the most accurate x/y position solution. >>> The idea is to get a location where you can see at least 2/3 of those >>> tracks when they are above about 20 degrees t

[time-nuts] ground plane for cheap helix antennas?

Hi, is there any benefit in adding a ground plane to these simple timing antennas? e.g. GPS-TMG-26N http://www.antenna.com/apg_products.cgi?id_num=11740 In which case, how big? And I'm imagining immediately underneath the antenna? This ublox note suggests probably not? http://www.u-blox.com/im

[time-nuts] Basic GPSDO finessing re frequency accuracy

Hi, Does anyone have any data / a feel for how ... antenna delay accuracy and/or elevation mask and/or hold position accuracy ... translate to frequency accuracy for short term measurement i.e. in the 1-10s tau range? That is, which should I focus on, which not? Kind Regards, Alan

Re: [time-nuts] June 30th leap second

I though this email (below) which I just received might be interesting. The emphasis is mine. It’s not just us then? Alan >>> On June 30, 2015, a leap second will be added to Coordinated Universal Time (UTC) at 23:59:59 UTC/19:59:59 Eastern Time. A leap second is a one-second adjustment that

Re: [time-nuts] Using CPLD/FPGA or similar for frequency

In my mind, at least, this is still the same subject… Does anyone have any results to share re the SiLabs Si53xx ‘Jitter Attenuating Clock Multipliers​’? Is this a helpful way to supply a 1GHz counter with a ‘0.1ps rms phase jitter’ clock? Alan ___ t

[time-nuts] Using CPLD/FPGA or similar for frequency

Hi, >>> So that turns into 2 games: How fast can you count? How many digits can you get in 1 second? <<< A clever interpolator for frequency or TIC would kill it - for TIC essentially a PICTIC on steroids. The PICTIC does 19pS with a 10 bit ADC and a 66MHz clock, an SR620 does 4pS with a 12

[time-nuts] Using CPLD/FPGA or similar for frequency

Hi, >>> This thread really makes me want to do an FPGA timing project. I have a Papilio One on hand, which uses the Spartan 3E. But what to do with it? It has to be something much more interesting than what a PicDiv or simple logic can do to make it worth my time. Hmm... <<< How about a 1pS

[time-nuts] TymServe 2100 1995 Issue - A Kludgy Fix

Hi, >>> It's not that simple. First, it's not 20 years, but 1024 weeks (19.6 years). And not UTC weeks (which may have leap seconds) but GPS weeks (which do not, and are always 604800 seconds long). etc <<< Don't think it's _that_ much code though. There's some open source ACM date algorit

Re: [time-nuts] Tymserve 2100 thinks it's 1995?

Hi, >>> You can claim that software costs nothing once you write the first copy. In the next breath we all expect to get ongoing customer support for that software and (e ) patches for this and that. When a vendor charges us by the year for that support we are unhappy. Would I love to

Re: [time-nuts] UBlox GPSDO

Re LEA-M8F >>> The main thing is that there is a lot of jitter at 10MHz (much less at >>> 8MHz) so you need to phase lock another oscillator to it. Yes, as they've got most of the guts of a basic GPSDO in there with a VCTCXO - but it seems they missed the boat in making the divisor for 10MHz

Re: [time-nuts] GPSDO disciplining algorithms

Hi all, Thanks for the interesting feedback everyone, and thanks Attila, for your specific references - some reading ahead. In principle, I should be able to remember all the stochastic / standard control theory, but I'm sure I'll have to 're-remember' it. An interesting point re 3 use-cases

Re: [time-nuts] GPSDO disciplining algorithms

Hi all, I'm interested in GPSDO disciplining algorithms - presumably the good ones are really well thought out stochastic control algorithms. Is it possible to point me to the seminal references / papers / datasheets that describe typical algorithms and the advantages and disadvantages of the v

Re: [time-nuts] Some observations of the BG7T BL GPSDO

Hi, > See performance plots, data files, and summary at > http://www.ke5fx.com/gpscomp.htm . Thanks to Bob, W7AVK for the loan of > the unit for testing! Would be curious to know if anyone else has > encountered a similar frequency error, or if the issue I saw was unique to > this particul