[time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Mark Sims]

Lady Heathe does have sidereal time support.  Set the time zone name to LMST or 
GMST or LAST or GAST and you get sidereal times...

  
___
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 instructions there.

Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Brooke Clarke]

Hi Skip:

The GPS orbit is 12 sidereal hours.  It sure would be nice if LH supported that 
time frame.
The ground track repeats for each satellite, so LH could also have a separate 
elevation mask for each of them.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

 Original Message 

Hello Nuts,

I am attaching a capture from Lady Heather of a 3-day run.  You can see the
temperature vary by 7C over each day.  The TB is being run open loop and
another GPSDO 10MHz input to the unit instead of the unit's oscillator.

I expected the purple line to repeat every 12 hours based on the GPS
constellation being the same (which maybe it kind of does), but there is
definitely a 24 hour repeat.  What is really weird is that the number of
satellites that LH sees also repeats on a 24 hour cycle, not 12 (bottom
trace).

Any help in understanding this behavior?  Thanks in advance.

Skip Withrow


Virus-free.
www.avast.com

<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>


___
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 instructions there.


___
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 instructions there.

Re: [time-nuts] Maser 0.7 nsec jumps solved

[Andy]

On Sun, May 22, 2016 at 11:15 PM, Jim Palfreyman  wrote:

As far as a remedy goes we are going to try a solid state relay that only
> switches on at 0V in the AC waveform. This should slow the inrush current,
> and hopefully the magnetic impulse.
>

If the load being switched on is inductive, it would be better to switch
the AC waveform at the voltage peaks, not at 0V.  This might seem
counter-intuitive, but it's real.  Switching on at the 0V crossing may
maximize the current pulse through the magnetics.

OTOH, if the origin of the impulse is mechanical in nature, neither remedy
may help.

Regards,
Andy
___
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 instructions there.

Re: [time-nuts] Simple solution for disciplining OCXO with 1 PPS

[Bob Camp]

Hi

Ok, so how would you do a pure analog GPSDO? 

The GPS receiver and that side of it are what they are. I’ll assume that you 
have a 1 pps out of a module. 

Your OCXO needs to get to 1 Hz via dividers. You can do that with digital 
dividers or with a chain of regenerative 
dividers. One is a bit more analog, the other may be “ok” under the “don’t go 
to crazy” ground rule. 

You now have a PPS that is off somewhere relative to the GPS. A push button 
will get them into rough alignment. 
Your OCXO is quite likely a bit high or low. A multi turn pot on the EFC will 
let you get it within 1x10^-9 without a
lot of crazy work. A reasonable counter tied to a reference will let you do 
this. 

Net result: The pps signals are roughly aligned and drifting < 1 ns / s. 
Considering the delta between them is 
bopping around by 10 ns, that’s quite good.  

Run a very normal bipolar charge pump off of the delta between the two pps 
signals. Fire a sample and hold when 
the transition is over. You now have a (maybe) +/- 60V signal that corresponds 
to the phase error. Since you are using
film capacitors, the 60V comes along for free. Taking it to the maximum is just 
a way to save money on caps. 

Next up, do a fairly simple 20 second time constant R/C filter. That will take 
out a lot of the hopping around and make 
the rest of the system a bit easier to quiet down. You now have a somewhat 
linear +/- 60V signal that tells you how
far off phase the setup is. After the RC you have a high input impedance / low 
drift buffer amplifier. Yes that’s a little 
tricky. 

Next you need a P and an I term. Both need to be variable as the system calms 
down. A rotary switch will do fine for 
this. Relays might also do the job. The P is a bank of resistors, each one to 
scale the buffered R/C to your control amp.
The I goes off to a similar set of resistors driving an integrator. Net time 
constant there will be in the 200 to 2,000 second range.
That’s were the ovenized caps come in. You also need a really good amp as part 
of the integrator to buffer out the signal. 

The nice thing about doing it this way is that you can *see* it all happening. 
There is a nice *clunk* noise as the filter 
steps off. Each number in the filter has a (likely large value) resistor that 
sets it up. To change the filter characteristics, 
you swap out resistors or twiddle pots. 

If you do the math, even with 60 V on the system, you probably don’t want 
anything over 1 meg ohm involved. At 2K seconds
that gets you to a pretty big film capacitor bank. Even the 20 second lowpass 
isn’t exactly small by the standards of fancy 
capacitors. 

There are a few interesting tidbits like wire wound / high value / low temp co 
resistors that would help things a bit. Swapping 
those in and out as you change filter settings experimentally could get a bit 
crazy. 

The net result should be a good starting point for a GPSDO. You still would 
need to spend all of the time working out values
and matching it up to your OCXO. The need for a good local reference and good 
measurement gear while doing this still is 
a limit, just like the pure digital approach. 

Bob



> On May 23, 2016, at 12:46 PM, Nick Sayer via time-nuts  
> wrote:
> 
> 
>> 
>>> If that sounds too weird, I am open to receive advises for a 
>>> microcontroller based solution.
>> 
>> If you want to go that way, probably the simplest solution would be to
>> take one of Nick Sayers boards, pull out the GPS receiver and feed the
>> PPS input from your GPS receiver.
> 
> It’d be kind of an awkward fit. For the OCXO/TCXO, you’d need to pull the 
> oscillator as well as the GPS (I believe you said you had an oscillator 
> already), and your EFC would be 1.65 volts wide centered on 1.65 volts. 
> That’s unlikely to be absolutely correct for your oscillator. You could 
> change around the Vref for the DAC, but at that point I’d consider 
> redesigning the board for your purposes instead.
> 
> That said, I think it’d be easy to adapt the circuit and code for a more 
> arbitrary setup. And I believe my system is good down to the ADEV 10E-11 
> level at tau 1s or so. I don’t know how much better it can do, as I’ve simply 
> not tried to go below that (and I likely couldn’t properly measure the 
> results anyway).
> 
> There’s also the FE-5680 board, but it has an RS-232 level shifter in place 
> of the DAC. On the other hand, it does have a very nice 2A @ 15V power 
> supply, which likely is very close to what you’d need for a really good OCXO. 
> A mash-up of that with the DAC put back in might be closer. But either way, 
> you’re designing a new board, I think.
> ___
> 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 instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to 

Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Peter Marczinowski]

Hi Tom,
IMHO in your point "2)" you should not mirror the -104 to +104, but add 180
degrees instead resulting in a final longitude of +76 after 12 hours. In
all other respects I agree.
Peter


Am Dienstag, 24. Mai 2016 schrieb Tom Van Baak :

> Hi Skip,
>
> > Any help in understanding this behavior?  Thanks in advance.
>
> Yes, GPS satellites do repeat every ~12 hours in orbit around the mass of
> the earth -- but -- you and the earth turns 180 degrees during those 12
> hours. So you're no longer where you should be when the 1st repeat occurs.
> Instead you have to wait yet another 12 hours for the earth to get back to
> the place where you were, in time to see the 2nd repeat. Now when you hear
> "get back, get back, get back to where you once belonged", you'll think of
> GPS satellites instead of the Beatles.
>
> So the LH plots are correct. Here's another take:
>
> 1) Say it's 6 PM MDT in Denver at lat/lon +39/-104 and you see a pattern
> of N satellites in the sky.
> 2) Tomorrow morning at 6 AM MDT that same pattern will be in the sky --
> not for you -- but for some guy at 6 PM lost in Inner Mongolia at lat/lon
> +39/+104.
> 3) Tomorrow evening at 6 PM MDT that same pattern will again be in the
> sky, this time for you in Denver.
>
> /tvb
>
> - Original Message -
> From: "Skip Withrow" >
> To: "time-nuts" >
> Sent: Monday, May 23, 2016 3:43 PM
> Subject: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)
>
>
> > Hello Nuts,
> >
> > I am attaching a capture from Lady Heather of a 3-day run.  You can see
> the
> > temperature vary by 7C over each day.  The TB is being run open loop and
> > another GPSDO 10MHz input to the unit instead of the unit's oscillator.
> >
> > I expected the purple line to repeat every 12 hours based on the GPS
> > constellation being the same (which maybe it kind of does), but there is
> > definitely a 24 hour repeat.  What is really weird is that the number of
> > satellites that LH sees also repeats on a 24 hour cycle, not 12 (bottom
> > trace).
> >
> > Any help in understanding this behavior?  Thanks in advance.
> >
> > Skip Withrow
> >
>
> ___
> 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 instructions there.
>
___
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 instructions there.

Re: [time-nuts] Looking for a Linux user with a Z3816/Z3815/HP5xxxx

[Clay Autery]

Just put the file on a server somewhere and email the link...  even drop
box...  It's a waste to send files through email anyway...  wastes tons
of bandwidth sending a file through an unnecessary number of interim
steps...

__
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 5/23/2016 6:22 PM, Mark Sims wrote:
> Alas,  it has become very hard to email an EXE file.  The ISPs are on to all 
> the tricks... zipping them,  renaming them, etc no longer work.  The net has 
> become a real nanny about protecting people from potential malware, etc.   
> Things like EXE files disguised as PDF file were/are a real threat and email 
> servers have gotten rather draconian about what they let through.
>
___
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 instructions there.

Re: [time-nuts] Looking for a Linux user with a Z3816/Z3815/HP5xxxx

[Bob Camp]

Hi

The quick and zero cost solution if it’s a point to point send — use something 
like We Transfer. As long
as you don’t go crazy on file size or sign up for their “pay for it” service, 
it works fine. 

Bob

> On May 23, 2016, at 8:47 PM, David Holland 
>  wrote:
> 
> Treat it like a virus.
> 
> zip -e -P password supersecretstuff.zip supersecretstuff.exe
> 
> It's more likely to get through.
> 
> On Mon, May 23, 2016 at 7:22 PM, Mark Sims  wrote:
>> Alas,  it has become very hard to email an EXE file.  The ISPs are on to all 
>> the tricks... zipping them,  renaming them, etc no longer work.  The net has 
>> become a real nanny about protecting people from potential malware, etc.   
>> Things like EXE files disguised as PDF file were/are a real threat and email 
>> servers have gotten rather draconian about what they let through.
>> --
>>> You can just remove the .exe extension on the file and have the
>>> recipient add it back on once the file is received.
>> ___
>> 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 instructions there.
> ___
> 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 instructions there.

___
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 instructions there.

Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Tom Van Baak]

Thanks to Hal and Peter for catching my sign/180 degree error.
This means Skip's nocturnal evil twin lives near the border of China / 
Tajikistan / Kyrgyzstan instead of Inner Mongolia. Here are the contrasting 
maps:

https://www.google.com/maps/@39.68,-104.902,600782m/data=!3m1!1e3
https://en.wikipedia.org/wiki/Denver

vs.

https://www.google.com/maps/@39.68,75.09,600782m/data=!3m1!1e3
https://en.wikipedia.org/wiki/Kashgar

Attached are the predicted GPS SV counts for the next 24 hours for each 
location. You can see they are almost identical. GPS sister cities.
Skip, let me know if these predictions sort of match what you actually observe.

/tvb

- Original Message - 
From: Peter Marczinowski 
To: Tom Van Baak ; Discussion of precise time and frequency measurement 
Sent: Monday, May 23, 2016 6:01 PM
Subject: Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)


Hi Tom,
IMHO in your point "2)" you should not mirror the -104 to +104, but add 180 
degrees instead resulting in a final longitude of +76 after 12 hours. In all 
other respects I agree. 
Peter


Am Dienstag, 24. Mai 2016 schrieb Tom Van Baak :

Hi Skip,

> Any help in understanding this behavior?  Thanks in advance.

Yes, GPS satellites do repeat every ~12 hours in orbit around the mass of the 
earth -- but -- you and the earth turns 180 degrees during those 12 hours. So 
you're no longer where you should be when the 1st repeat occurs. Instead you 
have to wait yet another 12 hours for the earth to get back to the place where 
you were, in time to see the 2nd repeat. Now when you hear "get back, get back, 
get back to where you once belonged", you'll think of GPS satellites instead of 
the Beatles.

So the LH plots are correct. Here's another take:

1) Say it's 6 PM MDT in Denver at lat/lon +39/-104 and you see a pattern of N 
satellites in the sky.
2) Tomorrow morning at 6 AM MDT that same pattern will be in the sky -- not for 
you -- but for some guy at 6 PM lost in Inner Mongolia at lat/lon +39/+104.
3) Tomorrow evening at 6 PM MDT that same pattern will again be in the sky, 
this time for you in Denver.

/tvb

- Original Message -
From: "Skip Withrow" 
To: "time-nuts" 
Sent: Monday, May 23, 2016 3:43 PM
Subject: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)


> Hello Nuts,
>
> I am attaching a capture from Lady Heather of a 3-day run.  You can see the
> temperature vary by 7C over each day.  The TB is being run open loop and
> another GPSDO 10MHz input to the unit instead of the unit's oscillator.
>
> I expected the purple line to repeat every 12 hours based on the GPS
> constellation being the same (which maybe it kind of does), but there is
> definitely a 24 hour repeat.  What is really weird is that the number of
> satellites that LH sees also repeats on a 24 hour cycle, not 12 (bottom
> trace).
>
> Any help in understanding this behavior?  Thanks in advance.
>
> Skip Withrow
>

___
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 instructions there.___
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 instructions there.

Re: [time-nuts] 1937 Time Standard

[paul swed]

Some good articles I have read several that you sent Tom. Its funny such
great information if you just search on the right terms.
But then I appreciate the fact that you sent great links. No guessing.
More to go and read.
Regards
Paul
WB8TSL

On Sat, May 21, 2016 at 4:50 PM, Tom Van Baak  wrote:

> Hi Thomas,
>
> > I was wondering if anyone knew what the "state of the art" time standard
> was in the 1937 ?
>
> The 1930's were an exciting time in this regard.
>
> The best time standards (in vacuum pendulum clocks) were those used by
> astronomers. Google: Shortt-Synchronome.
>
> Laboratory quartz clocks had just been developed. During this decade the
> best pendulum clocks were compared to the best quartz clocks. Google:
> Marrison Loomis Shortt
>
> And in the race between these two technologies, it was shown in 1936 by
> Scheibe and Adelsberger that irregularities seen by astronomers were due to
> the earth itself and not the pendulum or quartz clocks. This eventually led
> to the leap second. It was common to use a set of 3 clocks to do the
> comparison (sound familiar)
>
> To get a sense of the world of precise time in the 1930's I would
> recommend reading the following, each of which mentions something about the
> past century of timekeeping.
>
> The Evolution of the Quartz Crystal Clock
> http://www.ieee-uffc.org/main/history-marrison.asp
> https://ia902701.us.archive.org/25/items/bstj27-3-510/bstj27-3-510.pdf
>
> Time – the SI Base Unit “Second”, by Andreas Bauch
>
> https://www.ptb.de/cms/fileadmin/internet/fachabteilungen/abteilung_4/4.4_zeit_und_frequenz/pdf/2012_Bauch_PTBM_125a_en.pdf
>
> The Evolution of Time Measurement, Part 2: Quartz Clocks
> http://tf.boulder.nist.gov/general/pdf/2533.pdf
>
> Atomichron: The Atomic Clock from Concept to Commercial Product
> http://www.ieee-uffc.org/main/history-atomichron.asp
>
> Precision time and the rotation of the Earth, by Dennis McCarthy
>
> http://journals.cambridge.org/download.php?file=%2FIAU%2FIAU2004_IAUC196%2FS1743921305001377a.pdf
>
> Some Aspects of Precision Time Measurement -- 1930's German quartz, Lothar
> Rohde, etc.
> http://pubs-newcomen.com/tfiles/75ap119.pdf
> http://www.cdvandt.org/PTR%20quartz-clock.pdf
> http://www.cdvandt.org/CFQ.pdf
> http://www.cdvandt.org/BIOS-1316.pdf
>
> I have more links and PDF's to share. But let's first find out how deep an
> answer you actually want.
>
> Thanks,
> /tvb
>
> - Original Message -
> From: "Thomas D. Erb" 
> To: 
> Sent: Saturday, May 21, 2016 11:40 AM
> Subject: [time-nuts] 1937 Time Standard
>
>
> >I was wondering if anyone knew what the "state of the art" time standard
> was in the 1937 ?
> >
> >
> >
> >
> >
> >
> > ___
> > 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 instructions there.
> ___
> 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 instructions there.
>
___
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 instructions there.

Re: [time-nuts] 1937 Time Standard

[Tom Van Baak]

Thanks Paul.

I accumulate a pile of PDF's over time and when the right question shows up in 
the list I dig them out. It turns out Thomas, the OP, is doing a report on 
public clocks, including synchronous motor clocks. He added another source:
https://clockhistory.com/telechron/company/documents/warren_1937/index.html

The idea of time standards and time transfer methods has not changed over the 
centuries. What these guys did way back with telegraph (Western Union) or with 
60 Hz (Telechron) we now do with WWVB, NTP, GPS, etc. The decimal point moves.

The history of 60 Hz mains frequency, in particular, is extremely fascinating.
There's some basic intro here: 
https://en.wikipedia.org/wiki/Utility_frequency#History
Have a look at that table of frequencies used in 1897!

There's a great article (free, IEEE) on the use of 25 Hz at Niagara Falls:
http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4412948

And some wonderful information here:
http://ethw.org/Early_Electrification_of_Buffalo

Finally, this 3 part masterpiece:
http://ethw.org/Archives:Transformers_at_Pittsfield,_part_1
http://ethw.org/Archives:Transformers_at_Pittsfield,_part_2
http://ethw.org/Archives:Transformers_at_Pittsfield,_part_3

If nothing else, everyone should take a quick look at the photos in the above 3 
URL's. Mini-Circuit transformers these are not.

/tvb
  - Original Message - 
  From: paul swed 
  To: Tom Van Baak ; Discussion of precise time and frequency measurement 
  Sent: Monday, May 23, 2016 4:23 PM
  Subject: Re: [time-nuts] 1937 Time Standard


  Some good articles I have read several that you sent Tom. Its funny such 
great information if you just search on the right terms.
  But then I appreciate the fact that you sent great links. No guessing.
  More to go and read.
  Regards
  Paul
  WB8TSL


  On Sat, May 21, 2016 at 4:50 PM, Tom Van Baak  wrote:

Hi Thomas,

> I was wondering if anyone knew what the "state of the art" time standard 
was in the 1937 ?

The 1930's were an exciting time in this regard.

The best time standards (in vacuum pendulum clocks) were those used by 
astronomers. Google: Shortt-Synchronome.

Laboratory quartz clocks had just been developed. During this decade the 
best pendulum clocks were compared to the best quartz clocks. Google: Marrison 
Loomis Shortt

And in the race between these two technologies, it was shown in 1936 by 
Scheibe and Adelsberger that irregularities seen by astronomers were due to the 
earth itself and not the pendulum or quartz clocks. This eventually led to the 
leap second. It was common to use a set of 3 clocks to do the comparison (sound 
familiar)

To get a sense of the world of precise time in the 1930's I would recommend 
reading the following, each of which mentions something about the past century 
of timekeeping.

The Evolution of the Quartz Crystal Clock
http://www.ieee-uffc.org/main/history-marrison.asp
https://ia902701.us.archive.org/25/items/bstj27-3-510/bstj27-3-510.pdf

Time – the SI Base Unit “Second”, by Andreas Bauch

https://www.ptb.de/cms/fileadmin/internet/fachabteilungen/abteilung_4/4.4_zeit_und_frequenz/pdf/2012_Bauch_PTBM_125a_en.pdf

The Evolution of Time Measurement, Part 2: Quartz Clocks
http://tf.boulder.nist.gov/general/pdf/2533.pdf

Atomichron: The Atomic Clock from Concept to Commercial Product
http://www.ieee-uffc.org/main/history-atomichron.asp

Precision time and the rotation of the Earth, by Dennis McCarthy

http://journals.cambridge.org/download.php?file=%2FIAU%2FIAU2004_IAUC196%2FS1743921305001377a.pdf

Some Aspects of Precision Time Measurement -- 1930's German quartz, Lothar 
Rohde, etc.
http://pubs-newcomen.com/tfiles/75ap119.pdf
http://www.cdvandt.org/PTR%20quartz-clock.pdf
http://www.cdvandt.org/CFQ.pdf
http://www.cdvandt.org/BIOS-1316.pdf

I have more links and PDF's to share. But let's first find out how deep an 
answer you actually want.

Thanks,
/tvb


- Original Message -
From: "Thomas D. Erb" 
To: 
Sent: Saturday, May 21, 2016 11:40 AM
Subject: [time-nuts] 1937 Time Standard


>I was wondering if anyone knew what the "state of the art" time standard 
was in the 1937 ?
>
>
>
>
>
>
> ___
> 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 instructions there.
___
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 instructions there.


___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to 

Re: [time-nuts] Looking for a Linux user with a Z3816/Z3815/HP5xxxx

[Gary Woods]

On Mon, 23 May 2016 23:22:34 +, you wrote:

>Alas,  it has become very hard to email an EXE file.  The ISPs are on to all 
>the tricks..

Just stick it on one of the free file sharing sites or in your personal web
space, with nothing pointing to it except the link you send the
recipient(s).  Not that anything can stay hidden, but the ISP will likely
leave it along.  I've had an email client utility on mine for ages (no
longer really needed, since the author added the functionality to later
releases).

Or, hey, PGP encrypt it so the NSA will store a copy and try to crack it!


-- 
Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic
Zone 5/4 in upstate New York, 1420' elevation. NY WO G
___
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 instructions there.

Re: [time-nuts] Looking for a Linux user with a Z3816/Z3815/HP5xxxx

[David Holland]

Treat it like a virus.

zip -e -P password supersecretstuff.zip supersecretstuff.exe

It's more likely to get through.

On Mon, May 23, 2016 at 7:22 PM, Mark Sims  wrote:
> Alas,  it has become very hard to email an EXE file.  The ISPs are on to all 
> the tricks... zipping them,  renaming them, etc no longer work.  The net has 
> become a real nanny about protecting people from potential malware, etc.   
> Things like EXE files disguised as PDF file were/are a real threat and email 
> servers have gotten rather draconian about what they let through.
> --
>> You can just remove the .exe extension on the file and have the
>> recipient add it back on once the file is received.
> ___
> 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 instructions there.
___
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 instructions there.

Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Tom Van Baak]

Hi Skip,

> Any help in understanding this behavior?  Thanks in advance.

Yes, GPS satellites do repeat every ~12 hours in orbit around the mass of the 
earth -- but -- you and the earth turns 180 degrees during those 12 hours. So 
you're no longer where you should be when the 1st repeat occurs. Instead you 
have to wait yet another 12 hours for the earth to get back to the place where 
you were, in time to see the 2nd repeat. Now when you hear "get back, get back, 
get back to where you once belonged", you'll think of GPS satellites instead of 
the Beatles.

So the LH plots are correct. Here's another take:

1) Say it's 6 PM MDT in Denver at lat/lon +39/-104 and you see a pattern of N 
satellites in the sky.
2) Tomorrow morning at 6 AM MDT that same pattern will be in the sky -- not for 
you -- but for some guy at 6 PM lost in Inner Mongolia at lat/lon +39/+104.
3) Tomorrow evening at 6 PM MDT that same pattern will again be in the sky, 
this time for you in Denver.

/tvb

- Original Message - 
From: "Skip Withrow" 
To: "time-nuts" 
Sent: Monday, May 23, 2016 3:43 PM
Subject: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)


> Hello Nuts,
> 
> I am attaching a capture from Lady Heather of a 3-day run.  You can see the
> temperature vary by 7C over each day.  The TB is being run open loop and
> another GPSDO 10MHz input to the unit instead of the unit's oscillator.
> 
> I expected the purple line to repeat every 12 hours based on the GPS
> constellation being the same (which maybe it kind of does), but there is
> definitely a 24 hour repeat.  What is really weird is that the number of
> satellites that LH sees also repeats on a 24 hour cycle, not 12 (bottom
> trace).
> 
> Any help in understanding this behavior?  Thanks in advance.
> 
> Skip Withrow
> 

___
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 instructions there.

Re: [time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Bob Camp]

Hi

Well, *maybe* there is a 24 hour component in the GPS constellation :)

Indeed a lot of stuff repeats at the 24 hour point. The ionosphere is a bit 
different at midnight than at noon.

Bob

> On May 23, 2016, at 6:43 PM, Skip Withrow  wrote:
> 
> Hello Nuts,
> 
> I am attaching a capture from Lady Heather of a 3-day run.  You can see the
> temperature vary by 7C over each day.  The TB is being run open loop and
> another GPSDO 10MHz input to the unit instead of the unit's oscillator.
> 
> I expected the purple line to repeat every 12 hours based on the GPS
> constellation being the same (which maybe it kind of does), but there is
> definitely a 24 hour repeat.  What is really weird is that the number of
> satellites that LH sees also repeats on a 24 hour cycle, not 12 (bottom
> trace).
> 
> Any help in understanding this behavior?  Thanks in advance.
> 
> Skip Withrow
> 
> 
> Virus-free.
> www.avast.com
> 
> <#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> ___
> 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 instructions there.

___
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 instructions there.

Re: [time-nuts] Looking for Z3801 Power Supply Board

[paul swed]

Boy do I agree with Dave's comments. Even if the big block inverter is bad
it can all be replaced. I have a small inverting supply in my unit to
replace one leg. I think it was the -5V supply. Its been running for 7 plus
years.
Good luck
Regards
Paul
WB8TSL

On Mon, May 23, 2016 at 6:54 PM, Dave M  wrote:

> Dan,
> If you haven't already found the Z3801A page at
> http://www.realhamradio.com/GPS_Frequency_Standard.htm, you should read
> it thoroughly (in your case, especialy the section on the power supply).
> there is a good pictorial that shows locations of all the power supply test
> points. Using that pictorial, you should be able to determine which power
> supply is causing the problem (there are several).
>
> Otherwise, (I'm sure you're well aware) if you're set on getting a
> replacement PSU assembly, you're probably looking at buying a parts unit
> and salvaging the PSU board from it.  However, you might find that the
> parts unit also has a bad PSU.  It's a chance you take.
>
> Cheers,
> Dave M
>
>
>
> Dan Rae wrote:
>
>> My Z3801 power supply board has given up the ghost.  It had been
>> working well apart from an occasional Error 230 causing it to go into
>> Holdover for no good reason from time to time which may well be related of
>> course.
>> Does anyone have a good power supply from an otherwise dead unit which
>> might enable me to get it going again?
>>
>> I've had the darn thing for fifteen years and miss it :^)
>>
>> Dan
>>
>
>
> ___
> 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 instructions there.
>
___
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 instructions there.

Re: [time-nuts] Looking for Z3801 Power Supply Board

[Dan Rae]

On 5/23/2016 3:54 PM, Dave M wrote:

Dan,
If you haven't already found the Z3801A page at 
http://www.realhamradio.com/GPS_Frequency_Standard.htm, you should 
read it thoroughly (in your case, especialy the section on the power 
supply).  there is a good pictorial that shows locations of all the 
power supply test points. Using that pictorial, you should be able to 
determine which power supply is causing the problem (there are several).
Dave, it's completely dead.  I do have a schematic of the board (of 
uncertain origin), but I suspect it is one of the DC/DC convertors that 
is dead.  It just puts the power supply I'm feeding it from into tick 
mode but I can't find any obvious short anywhere.  It could be a 
Tantalum inside one of the aforesaid convertors, but it's not blown any 
pico fuses.


I will continue to puzzle over it...

Dan

___
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 instructions there.

[time-nuts] Looking for a Linux user with a Z3816/Z3815/HP5xxxx

[Mark Sims]

Alas,  it has become very hard to email an EXE file.  The ISPs are on to all 
the tricks... zipping them,  renaming them, etc no longer work.  The net has 
become a real nanny about protecting people from potential malware, etc.   
Things like EXE files disguised as PDF file were/are a real threat and email 
servers have gotten rather draconian about what they let through.
--
> You can just remove the .exe extension on the file and have the 
> recipient add it back on once the file is received.   
>   
___
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 instructions there.

Re: [time-nuts] Looking for Z3801 Power Supply Board

[Dave M]

Dan,
If you haven't already found the Z3801A page at 
http://www.realhamradio.com/GPS_Frequency_Standard.htm, you should read it 
thoroughly (in your case, especialy the section on the power supply).  there 
is a good pictorial that shows locations of all the power supply test 
points. Using that pictorial, you should be able to determine which power 
supply is causing the problem (there are several).


Otherwise, (I'm sure you're well aware) if you're set on getting a 
replacement PSU assembly, you're probably looking at buying a parts unit and 
salvaging the PSU board from it.  However, you might find that the parts 
unit also has a bad PSU.  It's a chance you take.


Cheers,
Dave M


Dan Rae wrote:

My Z3801 power supply board has given up the ghost.  It had been
working well apart from an occasional Error 230 causing it to go into
Holdover for no good reason from time to time which may well be related of
course.
Does anyone have a good power supply from an otherwise dead unit which
might enable me to get it going again?

I've had the darn thing for fifteen years and miss it :^)

Dan 



___
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 instructions there.

[time-nuts] I thought GPS repeated every 12 hours (-2 minutes)

[Skip Withrow]

Hello Nuts,

I am attaching a capture from Lady Heather of a 3-day run.  You can see the
temperature vary by 7C over each day.  The TB is being run open loop and
another GPSDO 10MHz input to the unit instead of the unit's oscillator.

I expected the purple line to repeat every 12 hours based on the GPS
constellation being the same (which maybe it kind of does), but there is
definitely a 24 hour repeat.  What is really weird is that the number of
satellites that LH sees also repeats on a 24 hour cycle, not 12 (bottom
trace).

Any help in understanding this behavior?  Thanks in advance.

Skip Withrow


Virus-free.
www.avast.com

<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
___
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 instructions there.

Re: [time-nuts] Nuclear transition for time reference - Nature 5-May, 2016, vol 533

[Poul-Henning Kamp]

In message 
, David Wit
ten writes:

>Much is published that comes to naught; I do not have knowledge to judge.
>But it seemed interesting to me.

Anything involving U233 sources is "interesting"...

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
___
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 instructions there.

Re: [time-nuts] Looking for a Linux user with a Z3816/Z3815/HP5xxxx

[Dave Daniel]

You can just remove the .exe extension on the file and have the 
recipient add it back on once the file is received.


DaveD


On 5/23/2016 1:42 PM, Mark Sims wrote:

I have added some code to Lady Heather to talk to SCPI GPSDOs (also Motorola, 
Ublox, and NMEA) and am looking for a guinea pig to test it...  I have a Z3801A 
and want to see if it is also 3815/3816/etc compatible.  Please contact me off 
list.
I might be able to send a WIndows .EXE , but a lot of ISP's want to block those 
 (you would need to first have Lady Heather installed from the ke5fx.com site)  
Most Linux people should easily be able to build it from the source files.


___
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 instructions there.


___
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 instructions there.

[time-nuts] Looking for Z3801 Power Supply Board

[Dan Rae]

My Z3801 power supply board has given up the ghost.  It had been working 
well apart from an occasional Error 230 causing it to go into Holdover 
for no good reason from time to time which may well be related of course.


Does anyone have a good power supply from an otherwise dead unit which 
might enable me to get it going again?


I've had the darn thing for fifteen years and miss it :^)

Dan

___
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 instructions there.

Re: [time-nuts] FE-5680A GPSDO controller also works with FE-5650A

[Nick Sayer via time-nuts]

> On May 23, 2016, at 11:34 AM, Skip Withrow  wrote:
> 
> Hello Time-Nuts,
> 
> Nick Sayer's GPSDO controller will also work with the FEI FE-5650A rubidium
> oscillators as well.  A small modification is needed to the board, but is
> rather trivial.
> 
> First, the 5680 outputs 10MHz on pin-7 of the DB-9, the 5650 has a separate
> SMA connector.  So, pin-7 needs to be lifted from the GPSDO board (the 5650
> has the VCXO monitor on that pin).  And a short coaxial pigtail needs to be
> run to ground and the GPSDO 10MHz input (I soldered the center conductor to
> the chip cap on the top of the board.  I also just use an SMA coaxial Tee
> to run the 10MHz to my monitoring equipment.
> 
> Second, the 5680 has an RS-232 interface and the 5650 is TTL.  So, the 5650
> can be modified for RS-232 (the pads are in the unit, the RS232 chip and 5
> caps must be added), or the RS-232 converter can be taken off Nick's board
> and two small jumpers added.  I have done both.
> 
> I have asked Nick to add changes on the next pass of the board to
> accommodate these changes more easily.

Big, huge thanks to Skip for not only recovering the 5680 that my early 
firmware bricked (that has not recurred, by the way, so I have some hope it’s 
all better now), but for being an independent tester of the prototype.

The revision of the board that’s on the way back to me has an error and the 
RS-232/TTL jumpers are, unfortunately, worthless. To do the TTL conversion for 
that version you have to pull the chip off, but as long as the first 3 
customers have 5680s, it won’t matter to them. Once I verify there are no other 
errors (I expect there are none), I’ll order a larger run with that error 
corrected.

The third jumper, however, does work properly and allows you to reroute the RF 
input from pin 7 to an on-board U.FL connector footprint. You can either add 
the U.FL SMT jack or just solder on to the center pad, and then swap around the 
two-way jumper. This is useful for other FEI oscillators like Skip’s modified 
5650s, or 5680s that have SMA output jacks.

This version also has an improved power supply compared to what Skip’s been 
using. I’ve been seeing improved results. Surprisingly (to me), it’s been 
improvements on the 5v rail rather than the 15v rail that have been the most 
beneficial.


___
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 instructions there.

[time-nuts] Looking for a Linux user with a Z3816/Z3815/HP5xxxx

[Mark Sims]

I have added some code to Lady Heather to talk to SCPI GPSDOs (also Motorola, 
Ublox, and NMEA) and am looking for a guinea pig to test it...  I have a Z3801A 
and want to see if it is also 3815/3816/etc compatible.  Please contact me off 
list.  
I might be able to send a WIndows .EXE , but a lot of ISP's want to block those 
 (you would need to first have Lady Heather installed from the ke5fx.com site)  
Most Linux people should easily be able to build it from the source files.

  
___
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 instructions there.

Re: [time-nuts] Get together at IMS?

[Richard (Rick) Karlquist]

I'll be there all day Wednesday.  I'll try to
meet you guys at 5 PM.

Rick Karlquist N6RK

On 5/22/2016 9:06 AM, Bernd Neubig wrote:

Agreed!
See you on Wed at 5.00pm at Booth 714 (Dynamic Engineers)

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Mark Kahrs
Gesendet: Sonntag, 22. Mai 2016 16:41
An: Discussion of precise time and frequency measurement 
Betreff: Re: [time-nuts] Get together at IMS?

I think this makes it real easy, let's meet at Bernd's booth at 5 p.m. on 
Wednesday.  Bring friends.



On Sat, May 21, 2016 at 3:46 AM, Bernd Neubig  wrote:


I will attend the IMS from Tuesday through Thursday noon time. Most
time I will be at booth 714 (Dynamic Engineers).
Good proposal to meet at the Industry reception on Wednesday. Please
come up with a proposal for the meeting point, as the hall is big.
Best regards

Bernd DK1AG

-Ursprüngliche Nachricht-
Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Mark
Kahrs
Gesendet: Freitag, 20. Mai 2016 15:13
An: Discussion of precise time and frequency measurement <
time-nuts@febo.com>
Betreff: [time-nuts] Get together at IMS?

Anyone else going to IMS in SFO this coming week?


I would propose meeting during the "industry Reception" Wednesday
afternoon...
___
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 instructions there.

___
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 instructions there.


___
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 instructions there.

___
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 instructions there.



___
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 instructions there.

[time-nuts] FE-5680A GPSDO controller also works with FE-5650A

[Skip Withrow]

Hello Time-Nuts,

Nick Sayer's GPSDO controller will also work with the FEI FE-5650A rubidium
oscillators as well.  A small modification is needed to the board, but is
rather trivial.

First, the 5680 outputs 10MHz on pin-7 of the DB-9, the 5650 has a separate
SMA connector.  So, pin-7 needs to be lifted from the GPSDO board (the 5650
has the VCXO monitor on that pin).  And a short coaxial pigtail needs to be
run to ground and the GPSDO 10MHz input (I soldered the center conductor to
the chip cap on the top of the board.  I also just use an SMA coaxial Tee
to run the 10MHz to my monitoring equipment.

Second, the 5680 has an RS-232 interface and the 5650 is TTL.  So, the 5650
can be modified for RS-232 (the pads are in the unit, the RS232 chip and 5
caps must be added), or the RS-232 converter can be taken off Nick's board
and two small jumpers added.  I have done both.

I have asked Nick to add changes on the next pass of the board to
accommodate these changes more easily.

These mods assume a 5650 that RDR-Electronics has modified to have the same
control word resolution as the 5680.

I hope to publish some Lady Heather plots soon of the GPSDO performance.
One nice feature is that Nick's code is open source and if people wanted to
add features (such as the EEPROM write) it should be easy to do.

I know I have had fun playing with the controller the last couple of seeks.

Regards,
Skip Withrow


Virus-free.
www.avast.com

<#DDB4FAA8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
___
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 instructions there.

Re: [time-nuts] Simple solution for disciplining OCXO with 1 PPS

[Nick Sayer via time-nuts]

> 
>> If that sounds too weird, I am open to receive advises for a microcontroller 
>> based solution.
> 
> If you want to go that way, probably the simplest solution would be to
> take one of Nick Sayers boards, pull out the GPS receiver and feed the
> PPS input from your GPS receiver.

It’d be kind of an awkward fit. For the OCXO/TCXO, you’d need to pull the 
oscillator as well as the GPS (I believe you said you had an oscillator 
already), and your EFC would be 1.65 volts wide centered on 1.65 volts. That’s 
unlikely to be absolutely correct for your oscillator. You could change around 
the Vref for the DAC, but at that point I’d consider redesigning the board for 
your purposes instead.

That said, I think it’d be easy to adapt the circuit and code for a more 
arbitrary setup. And I believe my system is good down to the ADEV 10E-11 level 
at tau 1s or so. I don’t know how much better it can do, as I’ve simply not 
tried to go below that (and I likely couldn’t properly measure the results 
anyway).

There’s also the FE-5680 board, but it has an RS-232 level shifter in place of 
the DAC. On the other hand, it does have a very nice 2A @ 15V power supply, 
which likely is very close to what you’d need for a really good OCXO. A mash-up 
of that with the DAC put back in might be closer. But either way, you’re 
designing a new board, I think.
___
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 instructions there.

[time-nuts] Nuclear transition for time reference - Nature 5-May, 2016, vol 533

[David Witten]

My knowledge in this area is superficial.  But I wondered if anyone in this
group had a reaction to the 5-May issue of nature that includes a 'News and
Views' piece and a formal article reporting the detection by Von der Wense
et al. of the 229m Thorium nuclear transition that is hoped to have utility
in time-related metrology applications?

The key point seems to be that since nuclear transitions of this sort
 involve shifts among excited states by quarks, which are governed by the
strong force, many of the electromagnetic perturbations of clocks governed
by electromagnetic force are eliminated.  (I think.)

Nuclear physics: Elusive transition spotted in thorium


Direct detection of the 229Th nuclear clock transition


Also significant appears to be the fact that the energy released is in a
region (~ 150-170 nm UV) where available lasers and other tools of the
trade can operate, allowing practical instruments to be constructed around
this transition.

Much is published that comes to naught; I do not have knowledge to judge.
But it seemed interesting to me.

Dave, KD0EAG
___
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 instructions there.

Re: [time-nuts] Simple solution for disciplining OCXO with 1 PPS

[Bob Camp]

Hi

Is a DAC in our out? 

I can (with some effort) build the entire computing engine needed for a GPSDO 
out
of 7400 series logic. It’s actually easier than you might think. Since that’s 
“small 
scale logic” is it in bounds? 

To me at least, analog is just that, no gates, no 1’s no 0’s, just a good old 
analog
computer. They went out of style a while back, but they still work …Once upon a 
time in a land far away, control theory labs made students set up loops on them 
and
do stuff like run motors :)

Bob

> On May 22, 2016, at 6:52 PM, Chris Albertson  
> wrote:
> 
> If you can build with small scale TTL gates you can save the need for
> a huge precision capacitor by storing the current EFC value in a
> 16-bit register/counter.  This 16-bit register drives a DAC.   Then
> you build a phase detector that can detect if the XO leads or lags the
> GPS.  If it leads you increment the counter, if it lags you decrement
> the counter.  Every second you either adjust the register or do
> nothing.   The DAC is nothing more than 16 precision resisters each
> one twice the value of the next one, each connected to one bit of the
> register by a transistor switch.
> 
> I would only implement this as exercise to show how cool 1970's
> technology was.   It would be far more impressive if you limited
> yourself to 1960's technology.  I say this because one of my other
> hobbies is building tube based audio gear.  The last thing I built was
> a spring reverb, using a steel spring as the delay.I already have
> the software version but the physical spring is more fun to use. I
> think a 60's or 70's vintage GPSDXO would be unique if strictly
> limited to period correct technology
> 
> On Sun, May 22, 2016 at 2:55 PM, Bob Camp  wrote:
>> Hi
>> 
>> Of course it’s possible, you simply need enough high quality film capacitors 
>> to make up the control loop integrator.
>> You probably also would use a pile of the same capacitors to slow down the 
>> PPS jitter a bit before it went into the loop.
>> The setup process would probably involve a bunch of toggle switches or 
>> relays to walk the loop into the long time constant
>> mode. You would be wise to put the caps all in some sort of oven 
>> arrangement. That way odd drafts hating the caps would
>> not drive the GPSDO nuts.
>> 
>> Bob
>> 
>>> On May 22, 2016, at 1:41 PM, Bernd Neubig  wrote:
>>> 
>>> Hello Fellow time-nuts,
>>> I am looking for a simple solution to discipline my 10 MHz reference OCXO 
>>> in my private lab with an 1 PPS signal from a separate GPS receiver.
>>> I am curious if there is a solution possible without programming a 
>>> microcontroller, as I am an old-fashioned "analogue" guy ;)
>>> I am well aware, that such a solution would have a lot of disadvantages, as 
>>> it cannot effectively compensate for short-term variations. However I would 
>>> be happy if such a KISS solution could achieve  a stability (STS) of better 
>>> 1E-10 over an hour. I know this is a damned long integration time for an 
>>> analogue integrator...
>>> If that sounds too weird, I am open to receive advises for a 
>>> microcontroller based solution.
>>> 
>>> Thanks a lot for your comments to come.
>>> BTW: you need not to teach me about basics of short-term stability. I just 
>>> want to evaluate the limits of a possible analogue solution. For sure, 
>>> that's not real disciplining, but more like a long-tau integration PLL
>>> 
>>> Best regards
>>> Bernd DK1AG
>>> 
>>> ___
>>> 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 instructions there.
>> 
>> ___
>> 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 instructions there.
> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> ___
> 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 instructions there.

___
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 instructions there.

Re: [time-nuts] Simple solution for disciplining OCXO with 1 PPS

[Bruce Griffiths]

The grid current of most tubes (apart from electrometer tubes operated at low 
voltage) is much larger than most FETs (apart from very large area ones).. The 
other issue with tube grid currents is that zero current corresponds to a 
delicate balance between electon and ion currents so the grid current noise can 
be somewhat larger than one may at first expect.
Bruce
 

On Monday, 23 May 2016 8:04 PM, David  wrote:
 

 On Sun, 22 May 2016 15:52:16 -0700, you wrote:

>...
>
>The DAC is nothing more than 16 precision resisters each
>one twice the value of the next one, each connected to one bit of the
>register by a transistor switch.

It will take beyond a heroic effort to get 16 bits of differential
non-linearity out of a binary weighted DAC.  It is difficult enough to
do with an R-2R ladder.

>I would only implement this as exercise to show how cool 1970's
>technology was.  It would be far more impressive if you limited
>yourself to 1960's technology.  I say this because one of my other
>hobbies is building tube based audio gear.  The last thing I built was
>a spring reverb, using a steel spring as the delay.    I already have
>the software version but the physical spring is more fun to use. I
>think a 60's or 70's vintage GPSDXO would be unique if strictly
>limited to period correct technology

I would not go back that far although with tube technology you do have
the capability of better than FET input impedance for long time
constants.  Chopping would be needed if offset drift below 10s of
microvolts is required.

I would like to try a mixed signal design using charge pumping into an
integrator.
___
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 instructions there.


  
___
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 instructions there.

Re: [time-nuts] Capturing a 1PPS signal with a Keysight 53230A

[Peter Membrey]

Hi guys,

Thanks for all the guidance!

I was ultimately able to make this work by applying various suggestions from 
the list. In the end I needed to offset the uBlox in order to get a good read 
and then fix this in post processing. I checked the pulse before and after 
making the offset, and the frequency seemed unaffected. Originally as part of 
the experiment I was considering the FS-725 as a perfect reference for 
simplicity (we all know that does not match reality) and if that assumption is 
made, it is possible where the pulses do overlap (that is they cross over and 
you start to see very large millisecond counts), to remove 1 second from the 
time and get the negative delta. Obviously this only works when you assume the 
reference is right even when it's wrong, which is not desirable in many cases.

However there was still a gotcha - it seems it is possible for it to "flip" 
within a single pulse so that you end up with some very strange results. I 
couldn't think of any good way to compensate for that so I went with the offset 
approach.

We did find some interesting things when looking at the performance of a 
relatively low cost GPS receiver (uBlox M8Q) when compared to the output of an 
SRS FS-725 which was being disciplined by the 1PPS of a Microsemi S650. We've 
got a paper being considered, but I'd love to share it here for critical 
feedback once it's published.

Thanks again to everyone!

Kind Regards,

Peter Membrey

- Original Message -
From: "Magnus Danielson" 
To: time-nuts@febo.com
Cc: mag...@rubidium.se
Sent: Monday, 23 May, 2016 08:38:50
Subject: Re: [time-nuts] Capturing a 1PPS signal with a Keysight 53230A

Hi,

On 05/02/2016 08:12 PM, Tom Van Baak wrote:
>> * DC
>> * 50Ohm
>> * Bandwidth filter enabled
>
> DC and 50R is ok. I would not use the filter; you want the fastest edge 
> possible.
>
> You forgot to mention the most important setting of all - the trigger 
> voltage. Check the signal at your inputs with a 'scope. I typically use 1.0 
> VDC, unless the 'scope suggests otherwise.

Oh, and turn of "auto" from trigger voltage, many counters tries to fix 
it way quicker than the PPS occurs. The 53131/132 has this issue with PPS.

Cheers,
Magnus
___
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 instructions there.
___
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 instructions there.

Re: [time-nuts] Maser 0.7 nsec jumps solved

[Poul-Henning Kamp]

In message 
, Jim Palfr
eyman writes:

>As far as a remedy goes we are going to try a solid state relay that only
>switches on at 0V in the AC waveform. This should slow the inrush current,
>and hopefully the magnetic impulse.

If that is not enough, consider a small VFD drive, and ramp up voltage+frequency
over 10 seconds.  It's slightly more intrusive, as you will need to remove the
starting capacitor from the motor to install the VFD.


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
___
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 instructions there.

Re: [time-nuts] Simple solution for disciplining OCXO with 1 PPS

[David]

On Sun, 22 May 2016 15:52:16 -0700, you wrote:

>...
>
>The DAC is nothing more than 16 precision resisters each
>one twice the value of the next one, each connected to one bit of the
>register by a transistor switch.

It will take beyond a heroic effort to get 16 bits of differential
non-linearity out of a binary weighted DAC.  It is difficult enough to
do with an R-2R ladder.

>I would only implement this as exercise to show how cool 1970's
>technology was.   It would be far more impressive if you limited
>yourself to 1960's technology.  I say this because one of my other
>hobbies is building tube based audio gear.  The last thing I built was
>a spring reverb, using a steel spring as the delay.I already have
>the software version but the physical spring is more fun to use. I
>think a 60's or 70's vintage GPSDXO would be unique if strictly
>limited to period correct technology

I would not go back that far although with tube technology you do have
the capability of better than FET input impedance for long time
constants.  Chopping would be needed if offset drift below 10s of
microvolts is required.

I would like to try a mixed signal design using charge pumping into an
integrator.
___
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 instructions there.

Re: [time-nuts] Capturing a 1PPS signal with a Keysight 53230A

[Magnus Danielson]

Hi,

On 05/02/2016 08:12 PM, Tom Van Baak wrote:

* DC
* 50Ohm
* Bandwidth filter enabled


DC and 50R is ok. I would not use the filter; you want the fastest edge 
possible.

You forgot to mention the most important setting of all - the trigger voltage. 
Check the signal at your inputs with a 'scope. I typically use 1.0 VDC, unless 
the 'scope suggests otherwise.


Oh, and turn of "auto" from trigger voltage, many counters tries to fix 
it way quicker than the PPS occurs. The 53131/132 has this issue with PPS.


Cheers,
Magnus
___
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 instructions there.