from:"djl"

[time-nuts] Re: DIY Low offset Phase Noise Analyzer (Erik Kaashoek)

2022-07-09 Thread djl via time-nuts

I checked the Hittite/AD part at Mouser, $21 and change. Problem is, 
they have a few, but it is marked obsolete/discontinued. Also, a 
devilish package to work with. . .



On 2022-07-08 22:19, Mike Monett via time-nuts wrote:

To Bob kb8tq. You wrote:


Hi



The noise floor of the double balanced mixer (used as a phase
detector at 100 MHz) is in the -165 go -170 dbc / Hz range. I've
used the parts you are talking about. Their floor is *way* higher.



Bob


I stated the MC100EP140 would not match the Hittite HMC984LP4E. It has
-231 dBc/Hz noise.

-231 dBc is *way* lower than -170 dbc. About 60 dB lower.

You might be interested in trying it. Only $13.25 at Arrow:

https://octopart.com/search?q=HMC984LP4E

Thanks,

Mike
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Run in circles, scream and shout.
(Naval War College Football Team)
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VOX: 406-626-4304
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[time-nuts] Re: NTP server source needed

2022-04-23 Thread djl

I forgot to put the famous number on my response. I've had a cost
effective NTP server # 255114568844 running for about 8 months with no
problems.

On 2022-04-23 14:14, shouldbe q931 wrote:

On Thu, Apr 21, 2022 at 9:23 AM Paul Watts wrote:

Long time lurker, first time poster.

In the past, I've purchased the LeoNTP server to act as a local time
server
on my work network. Unfortunately, those NTP servers aren't available
to

order.

I'm in need of two - three more NTP servers for various locations.

Do any of you have an alternate NTP server recommendation?

1. I'd like to keep the price less than $1,000. The Leo's were a
great,

self contained choice at less than $400.
2. Support for IPv4 is required and IPv6 is desired. The main
shortcoming I

have with the Leo's is no support for IPv6.
3. I'll serve about 150 clients per site from a given NTP server. My
NTP
clients are a combination of Windows and Linux computers along with
various
types of network gear (Cisco, Palo Alto, Aruba, Juniper). The Leo's
don't

even breathe hard at that level.
4. No PTP support is required. My timing needs are IT related - log
consistency, security protocol requirements, etc.
4. I'm not interested in building and using something like a Raspberry
Pi.
I'll be sending these to remote sites and don't want to worry about
issues

like memory card failures and the hobbyist feel of many Pi cases and
cooling options. That's fine for my home but not for work.
5. Availability is important.

Any suggestions are welcome.

Thanks,

Paul Watts.
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No connection to them, but these might fit
https://www.mouser.com/ProductDetail/NetBurner/PK70EX-NTP?qs=W62KBPEYc70bWh%252BpZOx83Q%3D%3D
and mouser appear to have stock.

Cheers

Arne
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Run in circles, scream and shout.
(Naval War College Football Team)
--
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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[time-nuts] Re: NTP server source needed

2022-04-23 Thread djl

I have had one of these running for about 8 months without a burp. Cost
effective, and probably available in bulk from the Old Country...

On 2022-04-23 14:14, shouldbe q931 wrote:

On Thu, Apr 21, 2022 at 9:23 AM Paul Watts wrote:

Long time lurker, first time poster.

In the past, I've purchased the LeoNTP server to act as a local time
server
on my work network. Unfortunately, those NTP servers aren't available
to

order.

I'm in need of two - three more NTP servers for various locations.

Do any of you have an alternate NTP server recommendation?

1. I'd like to keep the price less than $1,000. The Leo's were a
great,

self contained choice at less than $400.
2. Support for IPv4 is required and IPv6 is desired. The main
shortcoming I

like memory card failures and the hobbyist feel of many Pi cases and
cooling options. That's fine for my home but not for work.
5. Availability is important.

Any suggestions are welcome.

Thanks,

Paul Watts.
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No connection to them, but these might fit
https://www.mouser.com/ProductDetail/NetBurner/PK70EX-NTP?qs=W62KBPEYc70bWh%252BpZOx83Q%3D%3D
and mouser appear to have stock.

Cheers

Arne
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[time-nuts] Re: +1/f of transistors

2022-04-09 Thread djl


A very interesting dissertation. Pdf available.

On 2022-04-09 10:29, Lux, Jim wrote:

On 4/9/22 6:31 AM, Richard (Rick) Karlquist wrote:


I am seeing a lot of unsupported "theories" about what should be done 
to make devices with low 1/f noise.  It might be instructive for 
everyone
to read Marv Keshner's PhD dissertation (Stanford) discussing 1/f 
noise.



https://dspace.mit.edu/handle/1721.1/16024 is his MIT thesis.. Is that
what you're thinking of.

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Run in circles, scream and shout.
(Naval War College Football Team)
--
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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[time-nuts] Re: Potting compound advice needed

2021-11-11 Thread djl

I forgot to mention that it can be removed nicely with hot air, and has 
the very nice property that you can solder things that are coated just 
in case you should make a misteak. it is soft. I did not know the 
epsilon or tand.

Don

On 2021-11-11 17:49, Lux, Jim wrote:

On 11/11/21 4:00 PM, djl wrote:
I've used, wait for it, beeswax as a potting compound. Gouda cheese 
comes coated with it (some has paraffin, get the best,) in a lovely 
red. I also found out some years ago that Catholic churches use pure 
beeswax for large (not votive) candles and may give you the stubs. 
Nice, clean white.  Or, dear ol' Amazon has a huge assortment for 
around $1.00 / oz, in various stages of "purification". For expensive 
beeswax with some unknown sticky additives, use toilet mounting 
rings... (good also for preserving dry milsurp gunstocks, according to 
Anvil.)

73, Don



Beeswax, if perfectly dry, and no carbon residue, is pretty good RF
wise - at 1 MHz, epsilon is around 2.5, tan d is around 0.01 which is
ok, but not great. You could mix it with microballoons to lower
epsilon and dissipation.

It does shrink and, of course, it's pretty soft.


Pointing back to a previous suggestion 3M DP270 - that's 3.5 epsilon
and 0.018 tan d, but at 1kHz.  The graph in the datasheet does show
pretty constant 0.020 up to 1 MHz.

http://www.emesystems.com/pdfs/parts/DP270.pdf

At least it's available in less than a gallon quantities.

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[time-nuts] Re: Potting compound advice needed

2021-11-11 Thread djl

I've used, wait for it, beeswax as a potting compound. Gouda cheese 
comes coated with it (some has paraffin, get the best,) in a lovely red. 
I also found out some years ago that Catholic churches use pure beeswax 
for large (not votive) candles and may give you the stubs. Nice, clean 
white.  Or, dear ol' Amazon has a huge assortment for around $1.00 / oz, 
in various stages of "purification". For expensive beeswax with some 
unknown sticky additives, use toilet mounting rings... (good also for 
preserving dry milsurp gunstocks, according to Anvil.)

73, Don

On 2021-11-11 15:00, Gregory Beat via time-nuts wrote:

Rick -

Look at 3M Scotch-Weld Epoxy Potting Compound DP270.
https://www.3m.com/3M/en_US/p/d/b40066438/
I purchase from McMaster-Carr (Midwest pickup window is 2 miles from 
house).


This is what I have used, since it is rated for -65° to 350° F and
safe with copper (potting electronics, transformers, etc.)

***
Date: Wed, 10 Nov 2021 14:40:53 -0800
From: "Richard (Rick) Karlquist" 
Subject: [time-nuts] Potting compound advice needed
To: time and frequency measurement T
I am looking for help choosing a potting compound that
has the following properties:

1.  Good for 5,000VAC @ 1 MHz
2.  Low RF losses.
3.  Low permittivity is preferred
4.  Low tempco of permittivity is a want.
5.  Something I can implement in my home shop without access to a
vacuum pump etc. is a want.

Thanks in advance

Rick Karlquist N6RK
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[time-nuts] Re: pendulum

2021-11-03 Thread djl


FUN!

On 2021-11-03 06:23, folkert wrote:

Maybe a tiny bit on-topic but a nice watch nevertheless:
https://www.youtube.com/watch?v=DT5CafrZyDw

Syncing a pendulum to an audio synthesizer.
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[time-nuts] 10 mhz distribution

2021-09-24 Thread djl




https://www.sv1afn.com/en/gnss-gps/10-mhz-distribution-amplifier.html
has other interesting stuff...

The whole world is a straight man.
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PO Box 404, Frenchtown, MT, 59834
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[time-nuts] Re: in-ground clock room

2021-09-08 Thread djl

I think you can use precast concrete such as a septic tank or rings. My 
measurements made a LONG time ago in NM indicate that a mere 18 inches 
depth leads to less than one degree (God's units as revealed by the 
French) over the period of a year. Bring wiring in via a trench at the 
surface level of the top of the vault. Ideally, the cover should be 
insulation to near surface, then soil. That's the one sticky point 
because as you will know, thermal vortices will be set up in the vault 
air. very small slow fans may control?  The flow can be modeled,  I 
think.

Don

On 2021-09-08 19:54, Tom Van Baak wrote:

I am considering a below ground "clock room" away from the house. This
will be for some low-drift quartz oscillators and also a couple of
precision pendulum clocks. The goal is long-term, unattended, and very
undisturbed operation.

For scale, assume the room is 1 meter × 1 meter × 2 meters deep. So
that's vastly smaller than digging a basement, but much larger than
drilling a 8 inch round pipe. Digging down gives some natural
isolation and temperature regulation. A couple tons of concrete gives
high stability vertical walls for the pendulum clocks.

If any of you have personal or professional experience with the design
or construction of this sort of thing, especially experience with
precast (utility) vaults or poured concrete, please let me know.

In case this gets too off-topic for time-nuts, off-list email to me is
fine (t...@leapsecond.com).

Thanks,
/tvb
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PO Box 404, Frenchtown, MT, 59834
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[time-nuts] Re: Query about List and about 10 MHz Distro

2021-08-30 Thread djl

Hey: Don't forget that the cable itself is noisy when moved. Especially 
Teflon insulation.

Don

On 2021-08-30 06:51, Bob kb8tq wrote:

Hi

This sort of trouble with BNC’s has been going on a lot longer
than they have been coming in from China. A lot of folks use
them *way* past the point they should. They do indeed wear
out. They also come loose on the cable.

We went a bit nuts “killing off” all the BNC cables in the area
back in …errr … 1976. The result was a significant bump in the
supples budget that month and the elimination of a whole bunch
of problems on a number of tests. Back in that era Motorola
could afford to buy / fab a few cables.

Did the saved labor hours justify the expense? We claimed it
did……It most certainly made life easier.

Bob

On Aug 30, 2021, at 1:26 AM, Darren Freeman 
 wrote:


On Sun, 2021-08-29 at 09:21 -0500, Dana Whitlow wrote:

I believe that a significant problem in my case was not leakage
through the
shield, but
rather common-mode currents on the cable.  My experiences were with
RG-6
style cable,


Chiming in with a maybe tangential issue.

I had some really unreliable strange behaviour in my lab, and I traced
it to some low quality BNC crimp plugs. The noise at my receiver would
fluctuate by tens of dB, as I wiggled the connector. With a good
connector, it's dead quiet all of the time.

My conclusion was that the outer conductor was not making contact when
the plug was mated with a socket, and so outer currents were flowing
through the spring, and through the part of the plug that you rotate
when locking it to the socket. That adds some impedance, and your
receiver is now also listening to the common-mode current, that should
flow harmlessly to the chassis.

Visually, you can spot these particular bad plugs from the lack of
slots in the outer conductor. There's no way for it to compress as 
it's
mated with the socket, so they are under-sized instead. They often 
feel

loose. It may work sometimes, but not with all sockets, and only if
gravity is pulling on the cable just right.

All of the ones I've received from China have been like this. They 
went

in the bin. The ones from Jaycar, my local electronics shop, appear to
be identical. I used them anyway, because I was travelling a lot. 
Since

that time, I have been cutting them off my cables, hopefully I've
gotten them all.

It's been a sad lesson. Time and money down the drain, but at least I
worked out what was going on in the end.

Maybe someone else is struggling with this issue? Try wiggling all the
connectors :)

Have fun,
Darren
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[time-nuts] Re: Stanford Research SR620 GBIB

2021-08-28 Thread djl


Perhaps use the rs232 interface with a USB adapter?

On 2021-08-28 04:29, Julien Goodwin wrote:

On 28/8/21 5:33 pm, Volker Esper wrote:

Julien,
Can you please tell us wich GPIB-adapter you are using?
Thanks
Volker


Didn't have that info to hand when I wrote the mail, one of these:
http://www.galvant.ca/#!/store/gpibusb
(possibly an earlier rev, but there's nothing on the PCB to indicate,
other than a year of 2014)

I should have an alternative *somewhere* around here, but I doubt my
luck finding it, and it's a similar sort of device, just a different
implementation.


On 28/8/21 5:50 pm, Dave Baxter via time-nuts wrote:

I'd be inclined to check the SR620's exact needs re command/query
terminators, and also how exactly it terminates its responses.

From your description, it sounds like that sort of issue.

It may be, your GPIB device or its handler code is not recognising the 
end
of the instruments response, and also buffers are not being flushed 
before

starting another query transaction.

So youre software get "out of step" between what it sends to the 
instrument

and what it sees coming back.

The eventual lockup, is also indicating potential buffer problems.


I absolutely agree, except that it's not quite consistent behavior, and
it's just the SR620 that does it.

If I was consistently getting a reading delayed every time I'd assume
one of the commands is responding that I don't expect, but that's not
what it seems to be.

Possibly adding a few extra sleep calls into my init code will help.

You need to see "exactly" what data is happening on the GPIB itself, 
does

your device/support code have any sort of bus analyzer capability?


Nope, I could rig up an adapter on my MSO scope, or possibly pick up an
old HP one, but the cost in almost any of these options (especially by
the time you include shipping to Australia) is getting up there with
just buying a newer HPAK counter.

Given that such a logic analyser adapter is easy enough to design that 
I
might as well do that, putting the PCBs and connectors on my next 
orders

with those suppliers.


73.

Dave G8KBV.


Message: 4
Date: Sat, 28 Aug 2021 17:03:09 +1000
From: Julien Goodwin 
Subject: [time-nuts] Stanford Research SR620 GBIB
To: Discussion of precise time and frequency measurement

Message-ID: <4e137f33-67e5-c00c-0293-16276e591...@studio442.com.au>
Content-Type: text/plain; charset=utf-8

For an upcoming (very time-nutty, and hopefully to be shared soon)
project I need to finally do some frequency datalogging.

I've had a Stanford SR620 sitting around, and plugged it in to a handy
GPIB adapter (*not* a major commercial one, one of the community 
ones).


While I can get it to talk GPIB there seems to be some reliability
issues, with what looks to be some form of read buffering happening,
with measurement results coming in as the answer to some later 
command.


A few times I've even restarted it as it stopped responding (luckily
that hasn't happened once measurements had started).

Since I'm hoping to actually use measurements as part of a control 
loop

this is obviously a bad thing.

Does anyone have any experience with the SR620 & GPIB as to why this
might be happening?

I've not experienced this with other instruments (ancient HP, modern
Keysight, recent Keithley, 90s Anritsu) I've used with the same GPIB
adapter.

The SR620 has version 1.48 firmware.

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Today's Topics:

   1. Re: Leviton VTP24 Is this Time Accurate enough? (Dana Whitlow)
   2. Re: Leviton VTP24 Is this Time Accurate enough? (Lux, Jim)
   3. Re: uncertainty/SNR of IQ measurements (Joseph Gwinn)
   4. Stanford Research SR620 GBIB (Julien Goodwin)


--

Message: 1
Date: Fri, 27 Aug 2021 05:30:14 -0500
From: Dana Whitlow 
Subject: [time-nuts] Re: Leviton VTP24 Is this Time Accurate enough?
To: Discussion of precise time and frequency measurement

Message-ID:

Content-Type: text/plain; charset="UTF-8"

If my watch were that bad, I'd toss it out and go shopping for a new 
one.

I wonder if Leviton offers a version with an external ref input.

Dana


On Fri, Aug 27, 2021 at 12:12 AM D. Resor  
wrote:



I inquired with Leviton as to the accuracy of the VTP24 24 Hour
Programmable
Timer with DST.

https://www.leviton.com/en/products/vpt24-1pz

Don Resor

Here is the reply I received:

Hello,

Thank you for contacting Leviton technical support. According to the 
code

it
meets, it is required to have time keeping accuracy

[time-nuts] Re: Comparison/evaluation of u-blox timing receivers

2021-08-28 Thread djl

John: I missed this on its intro to the group. Great paper and effort.
It's also a very useful intro/primer to measurement methodology beyond
application to only the u-blox family. Thanks for leveraging the NSF for
our benefit!

Don

On 2021-08-28 05:02, Julien Goodwin wrote:

On 24/8/21 11:51 am, John Ackermann N8UR wrote:

In 2020 I did an extensive evaluation of the timing ability of the
u-blox LEA-M8F, NEO-M8N, NEO-M8T, NEO-M9N, ZED-F9P, and ZED-F9T. The
work was made possible by support from the HamSci consortium
(https://hamsci.org) under NSF grants supporting HamSci activities.

I was sure I'd posted about the paper on time-nuts, but I can't find
any

record that I did, so this is a belated announcement. It's available
for download from

https://hamsci.org/sites/default/files/publications/2020_TAPR_DCC/N8UR_GPS_Evaluation_August2020.pdf

As BobC says, "Lots of fun!"

Neat.

For a project I might eventually get back to I was looking at using the
M8F controlling an external oscillator. I built a test board[1], but I
stopped once I had the GPS working, I can't recall if I even enabled
the

control of the external oscillator, but I certainly didn't make any
attempt to characterize it.

Once I get my frequency datalogging issue solved for my other project I
might try and see what I get.

1: https://laptop006.livejournal.com/60072.html the DAC, oscillator and
supporting components are all in the bottom-left.
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PO Box 404, Frenchtown, MT, 59834
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[time-nuts] Fwd: Your request in Real-Time HAT

2021-08-19 Thread djl


Here's the quote I received for the hat:

 Original Message 

SUBJECT:
Your request in Real-Time HAT

DATE:
2021-08-19 05:23

FROM:
Andreas Foglar 

TO:
"d...@montana.com" 

Dear Mr. Latham,

Thanks for your interest in our Real-Time HAT for Raspberry Pi.

There is a lot of information about it in the web:

0. Homepage: https://innoroute.com/realtimehat/ [1]

1. System Description: https://innoroute.com/download/systemdescription/ 
[2]


2. Operation Manual: https://github.com/InnoRoute/RealtimeHAT [3]

3. Image download: https://my.hidrive.com/share/3ugldbuowd#$/ [4]

4. Pin Assignment: https://pinout.xyz/pinout/real_time_hat# [5]

5. Instruction Videos: 
https://www.youtube.com/channel/UCX-0AXp_XrxDvd4bfO6ZMBQ [6]


6. Papers: https://www.researchgate.net/project/Raspberry-Real-Time-HAT 
[7]


The current price of the 3-port device is 400 EUR.

With best regards,

Andreas Foglar

InnoRoute CEO

Phone +49-89-8776-7567

Telegram/ Signal +49-160-9726-5646

Skype afoglar

Mail fog...@innoroute.com

www.innoroute.com [8]

https://www.linkedin.com/in/andreasfoglar/ [9]

Marsstr. 14a, D80335 Munich, Germany

New request for Real-Time HAT 2-port

Details:

Name: Don Latham

Company: Six Mile Systems LLC

E-Mail: d...@montana.com

Requested Type: Real-Time HAT 2-port

Reason: other:

Quantity: 1

Additional information:


The whole world is a straight man.
--
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

Links:
--
[1] https://innoroute.com/realtimehat/
[2] https://innoroute.com/download/systemdescription/
[3] https://github.com/InnoRoute/RealtimeHAT
[4] https://my.hidrive.com/share/3ugldbuowd#$/
[5] https://pinout.xyz/pinout/real_time_hat
[6] https://www.youtube.com/channel/UCX-0AXp_XrxDvd4bfO6ZMBQ
[7] https://www.researchgate.net/project/Raspberry-Real-Time-HAT
[8] http://www.innoroute.com/
[9] https://www.linkedin.com/in/andreasfoglar/
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[time-nuts] interesting time hat for RPi

2021-08-19 Thread djl


See:
https://hackaday.com/blog/?s=Raspberry+Pi+HAT+for+IEEE1588

I got a quote; a 3 port hat is 400 Euro. You'll have to decide. Comments 
very welcome.

Don


The whole world is a straight man.
--
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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[time-nuts] interesting clock

2021-08-08 Thread djl




https://hackaday.io/project/180005-a-digital-real-time-clock


The whole world is a straight man.
--
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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[time-nuts] Re: Thunderbolts ...

2021-07-18 Thread djl


Newer module:  $650.00   meh

On 2021-07-17 19:45, Gary E. Miller wrote:

Yo Dave!

On Sat, 17 Jul 2021 00:06:42 +0100
Dave  wrote:


I'm a bit of a newbie at this, but is it possible to buy thunderbolts


WHy?  They newer Trimble GNSS timing modules work beter.  Like the ICM 
SMT 360:


https://timing.trimble.com/products/gnss-receivers/icm-smt-360-multi-gnss-timing-module/


If so, where ?


Hobbyist GNSS receivers are in short supply.  You gotta look harder 
than

before COVID.

An ICM SMT 360 on a carrier board is $125:

https://novotech.com/icm-smt-360-337.html

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588

Veritas liberabit vos. -- Quid est veritas?
"If you can't measure it, you can't improve it." - Lord Kelvin

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PO Box 404, Frenchtown, MT, 59834
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[time-nuts] Re: GPS antenna distribution???

2021-06-27 Thread djl

4-port: ttps://www.sv1afn.com/en/gnss-gps/-7.html  99euro I have one 
works fine

Don

On 2021-06-27 15:06, Georg Sauthoff wrote:

Hello,

On Sat, Jun 26, 2021 at 11:49:26PM -0400, lstosk...@cox.net wrote:

I seem to have an gathering of GPS antenna on my window ledge.  I seem
to have missed info on building a splitter/amp to take one signal and
distribute it.  Quick reference?  N0UU


Sysmocom has a 16-channel GPS antenna splitter:

https://sysmocom.de/products/lab/gps-spl16/index.html

Best regards
Georg
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[time-nuts] A tale of two NTP servers

2021-04-25 Thread djl

A while back, I decided to try putting together a small, gps local NTP 
server. I have several computers on a lan and wanted to serve them all 
with a locally controlled device.  A bit of research  (raspberry pi gps 
ntp server --in my searcher) came up with several instructive 
sites.Seemed easy.  Is there a kit? so my current theory of buy the 
biggest piece possible can be carried out?  Further consult of youtube 
came up with:


https://www.youtube.com/watch?v=VrDRAVy_bg4_channel=JohnMiller

I saw something from John on the time-nuts forum in the past, so 
contacted him re the hat he had for sale. The youtube presentation was 
so clear and complete that I bought one of his hats with the 
accompanying sd card. So I bought in.  I put the hat on a PiB on hand, 
put the antenna outside my window, and inserted the sd card as 
instructed. Before the video was completely finished, the server was 
running and connected to a Linux machine I had tunning nearby. As 
advertised. In detail. No fuss, no muss, and it's still going strong 
after two months and two power outages. WELL DONE JOHN!!!


But what about a ready to run little server? well, there are several 
around. BUT, they're kinda expensive compared to the RPi setups in 
various forms.  I'm sort of a sucker for the cheap (er, inexpensive) 
Chinese modules for various uses available on ebay or alibaba or other 
sources. Apparently, a factory somewhere in Guangdong "designs" and 
makes a bunch of litte modules to do something like measure voltagews, 
generate frequencies, etc. These modules are then bought by the 
relatives of the maker and sold on the outlets for various prices. The 
problem with these modules is that there is NEVER any documentation. 
You're on your own to use all your wiles, including reverse engineering, 
perusal of ham radio sources, eval info from manufacturers of the ripped 
chip designs, etc.  Despite that, for me at least, the modules have been 
cost effective. Always buy at least two.
With that in mind, I hit ebay and came up with: 363361419214 as an 
example. Seemed a bit expensive, but supposed to be plug and play, wit 
antenna and power. So, I ordered one up and hit the documentation trail. 
Nothing!  So, contacted the seller via ebay, and, after a brief hiatus 
for Chinese new year, got what there is for documentaton. Mostly in 
Chinese. But, I was able to find the address of the device using ANGRY 
lan scanner (you do use that, no? a great piece of software!)  
(192.168.0.100 btw).  And that worked too. It's still working. Removing 
it's pants revealed a UBLOX and a 32 bit processor, with some glue 
chips. real simple.


One further note, I'm using one antenna for the two devices, courtesy of 
SV1AFN (https://www.sv1afn.com/en/gnss-gps/-7.html) who makes a bunch of 
good stuff.


So, it can be done. As for me, I would get the PI hat and go that way, 
simply because it is not a black box, and other things are possible 
using that setup. On the other hand, for less cost, the ebay module was, 
once te secrets have been pried out, is totally simple to implement.


I have not tried to compare these units in any way, as there are those 
of you who are far more experienced than I am. All I know is, these 
approaches worked.


As usual, YMMV
73, Don

--

The whole world is a straight man.:
--
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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[time-nuts] Re: Fwd: FE-5680A Calibrator program by Bob Campbell VK4XV

2021-03-26 Thread djl


share?

On 2021-03-26 12:18, DM wrote:

The search is complete!! A friend sent me what appears to be the full
package, the .exe and source code (although the source code is all
Greek to me).
I'll be playing with that in a few day & see if it will do what I
need. My FE-5680A has aged a bit over the years and I'd like to get it
back on track. Hopefully, this program will help with that.
Thanks to all who replied.

DaveM


From: "DM" 
To: time-nuts@lists.febo.com
Sent: Thursday, March 25, 2021 4:42:55 PM
Subject: FE-5680A Calibrator program by Bob Campbell VK4XV

I've run across several references to a FE-5680A Calibrator program by
Bob Campbell VK4XV, but searches for it have been quite unfruitful.
Does anyone have a link to it, or know how to get in touch with Bob
Campbell? I've searched for his web site, but it seems to have gone
into never-never land.

Thanks for any help,
DaveM

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The whole world is a straight man.
--
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304
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Re: [time-nuts] World's most precise.... wall clock

2021-03-03 Thread djl

Hi John:   What's the cost of the CSAC GPSDO? I'd ask directly, but the 
exact device specification seems a bit murky.

Thanks

On 2021-03-03 10:34, John Sloan wrote:

I’ve built several small home-brew NTP servers using a Raspberry Pi,
a GPS receiver, and an LCD display. Most of them are desk clocks.
My favorite one (and the biggest money sink) is a mantle clock in my
living room that incorporates a chip-scale cesium “atomic clock”.

Photo: https://flic.kr/p/2kqoHC7

Blog article:
https://coverclock.blogspot.com/2017/05/my-stratum-0-atomic-clock_9.html

Git repo: https://github.com/coverclock/com-diag-astrolabe

--
J. L. SloanDigital Aggregates Corp.
+1 303 940 9064 (O)3440 Youngfield St. #209
+1 303 489 5178 (M)Wheat Ridge CO 80033 USA
jsl...@diag.comhttp://www.diag.com 


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--
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304


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[time-nuts] useful stuff

2021-02-01 Thread djl


https://www.sv1afn.com/en/  has some useful stuff for GPS and 10 MHz.
Don

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The whole world is a straight man.
--
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304


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[time-nuts] ntp server

2021-01-26 Thread djl


Has anyone tried one of these ebay offerings?  opinions?
15ns/1pps 0.5-2ms Network NTP Time Server for GPS Beidou GLONASS Galileo 
QZSS


124133795048
Don

--

The whole world is a straight man.
--
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304


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Re: [time-nuts] Long Wave Radio-Frequency standard testing

2021-01-15 Thread djl

Sorry, forgot to include the cite:
LATHAM, D. Diurnal Frequency Variation and Refraction Index. Nature 
Physical Science 234, 157–158 (1971). 
https://doi.org/10.1038/physci234157a0

Don

On 2021-01-15 15:13, Andy Talbot wrote:
I did a plot of the phase of the UK 198kHz longwave transmission to me, 
a

path of about 150km, compared against an HP5061A Caesium standard
N

early 24 hours duration, covering night time and day time propagation 
in

October.

You can observe the wild wandering of both phase and amplitude  during
night time due to skywave/groundwave interaction as the ionosphere 
shifts

around.

Plot also at
http://www.g4jnt.com/DropF/droitwichplot2a.bmp
if the attachment doesn't get through

[image: DroitwichPlot2a.bmp]
Andy
www.g4jnt.com

Virus-free.
www.avg.com

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, 15 Jan 2021 at 21:55, Gilles Clement  
wrote:

Hi JF,
DCF77 is more distant, less powerful and probably more polluted 
(77kHz).

Anyhow I would probably not be able to measure better than 10e-11 with
current setup (need a better reference)
Indeed a good and stable phase lock was not easy to reach.
I experienced the day and night huge differences (as documented in 
post)

but nothing specific to phase shifts during sunrise or sunset.
No big difficulties with the ferrite antenna and the receiver design
either (thanks to good stuff from the old radio days probably).
Found that magnetic field antenna (ie: ferrite) appeared much less
sensitive to pollution than electric field antennas.
Naturally bad experience with Led bulbs and vapor gas lamps. You have 
to
chase them all and change to old filament lamps in and around the lab. 
No

issues with computers though.
What I found most challenging (and hence interesting) was the 
following :

- Temperature control, high resolution and high stability (Crystal
oscillator but also for the controller parts, ADC, DAC… )
- PI loop stability (very tricky)
- Matching theory with practice (still work in progress…!)
- Understanding the logic and physics behind behaviors, the real root
cause of problems,
and especially why a « really clever » enhancement - more than often -
actually leads to… performance degradation...
Gilles.

> Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts <
time-nuts@lists.febo.com> a écrit :
>
> Hi,
> 800Kw according to the press release of ANFR. I doubt it is the best
choice : DCF77 is more precise (active hydrogen maser) but a little 
bit

more distant...
> But the phase lock of a quartz on a VLF signal is not as easy. There is
a considerable phase shift in the evening and in the morning with the 
sun

position, big instabilities at these moments and you have a hudge
difference between day and night (10 e-9/8)... Have a look at the 
Adret

receiver 4101 with its step motor phase lock...The engineering of the
ferrite road antenna is very tricky : temperature coefficient of the
ferrite, subtle tiny out of resonnace tuning, problem of the 
interferences
from domestic electrnic pollution (computers with sync of monitors, 
led

drivers...). The archiyecture of the receiver is also tricky : no AGC
(introduces phaseshift), heavy filtering (where : antenna, 
receiver...)

> On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <
clemg...@gmail.com> wrote:
>
> Hi,
>
> This is to share current results on a "Long Wave RadioFrequency
Standard" project I have been pursuing for a while.
> Attached are typical ADEV plots and a block diagram of the system.
>
> I live in a crowded city (Paris, France) with no - or very limited -
access to open sky. Not good for GPS.
> However a long wave broadcasting public service is (still) available,
broadcasting time signal for clocks.
> The transmitter is located in Allouis, central France (200km for Paris).
> The signal is quite powerful (1MW) and the carrier (162kHz ) is
stabilized with a Cesium-standard.
>
> I decided to test how far I could go in disciplining a local VCO with
this signal.
>
> As well known, long wave RF has interesting features:
> - Signal is available (almost) everywhere, anytime, in the country
especially inside buildings (even underground !)
> - Quite stable and strong ground wave in day time.
> - Relatively easy antenna and RF signal processing (ferrite rod)
> And there are naturally a number of drawbacks (especially with the
Allouis signal) such as:
> - Much more unstable signal at night (interferences with ionospheric
path)
> - Large phase modulation of the carrier (time signals bits +/- 1 rad
phase modulated).
> - RF perturbations on the signal path.
> -Stop broadcasting for maintenance every Tuesday morning….
>
> Design of the « LWRFDO » was derived and inspired from many references
(including this list naturally).
> Principles are summarized in the attached

Re: [time-nuts] Long Wave Radio-Frequency standard testing

2021-01-15 Thread djl

Longwave phase is dependent on the weather between your receiver and the 
transmitter...



On 2021-01-15 15:13, Andy Talbot wrote:
I did a plot of the phase of the UK 198kHz longwave transmission to me, 
a

path of about 150km, compared against an HP5061A Caesium standard
N

early 24 hours duration, covering night time and day time propagation 
in

October.

You can observe the wild wandering of both phase and amplitude  during
night time due to skywave/groundwave interaction as the ionosphere 
shifts

around.

Plot also at
http://www.g4jnt.com/DropF/droitwichplot2a.bmp
if the attachment doesn't get through


[image: DroitwichPlot2a.bmp]
Andy
www.g4jnt.com




Virus-free.
www.avg.com

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, 15 Jan 2021 at 21:55, Gilles Clement  
wrote:



Hi JF,
DCF77 is more distant, less powerful and probably more polluted 
(77kHz).

Anyhow I would probably not be able to measure better than 10e-11 with
current setup (need a better reference)
Indeed a good and stable phase lock was not easy to reach.
I experienced the day and night huge differences (as documented in 
post)

but nothing specific to phase shifts during sunrise or sunset.
No big difficulties with the ferrite antenna and the receiver design
either (thanks to good stuff from the old radio days probably).
Found that magnetic field antenna (ie: ferrite) appeared much less
sensitive to pollution than electric field antennas.
Naturally bad experience with Led bulbs and vapor gas lamps. You have 
to
chase them all and change to old filament lamps in and around the lab. 
No

issues with computers though.
What I found most challenging (and hence interesting) was the 
following :

- Temperature control, high resolution and high stability (Crystal
oscillator but also for the controller parts, ADC, DAC… )
- PI loop stability (very tricky)
- Matching theory with practice (still work in progress…!)
- Understanding the logic and physics behind behaviors, the real root
cause of problems,
and especially why a « really clever » enhancement - more than often -
actually leads to… performance degradation...
Gilles.



> Le 15 janv. 2021 à 16:57, JF PICARD via time-nuts <
time-nuts@lists.febo.com> a écrit :
>
> Hi,
> 800Kw according to the press release of ANFR. I doubt it is the best
choice : DCF77 is more precise (active hydrogen maser) but a little 
bit

more distant...
> But the phase lock of a quartz on a VLF signal is not as easy. There is
a considerable phase shift in the evening and in the morning with the 
sun

position, big instabilities at these moments and you have a hudge
difference between day and night (10 e-9/8)... Have a look at the 
Adret

receiver 4101 with its step motor phase lock...The engineering of the
ferrite road antenna is very tricky : temperature coefficient of the
ferrite, subtle tiny out of resonnace tuning, problem of the 
interferences
from domestic electrnic pollution (computers with sync of monitors, 
led

drivers...). The archiyecture of the receiver is also tricky : no AGC
(introduces phaseshift), heavy filtering (where : antenna, 
receiver...)

> On Friday, January 15, 2021, 03:54:40 PM GMT+1, Gilles Clement <
clemg...@gmail.com> wrote:
>
> Hi,
>
> This is to share current results on a "Long Wave RadioFrequency
Standard" project I have been pursuing for a while.
> Attached are typical ADEV plots and a block diagram of the system.
>
> I live in a crowded city (Paris, France) with no - or very limited -
access to open sky. Not good for GPS.
> However a long wave broadcasting public service is (still) available,
broadcasting time signal for clocks.
> The transmitter is located in Allouis, central France (200km for Paris).
> The signal is quite powerful (1MW) and the carrier (162kHz ) is
stabilized with a Cesium-standard.
>
> I decided to test how far I could go in disciplining a local VCO with
this signal.
>
> As well known, long wave RF has interesting features:
> - Signal is available (almost) everywhere, anytime, in the country
especially inside buildings (even underground !)
> - Quite stable and strong ground wave in day time.
> - Relatively easy antenna and RF signal processing (ferrite rod)
> And there are naturally a number of drawbacks (especially with the
Allouis signal) such as:
> - Much more unstable signal at night (interferences with ionospheric
path)
> - Large phase modulation of the carrier (time signals bits +/- 1 rad
phase modulated).
> - RF perturbations on the signal path.
> -Stop broadcasting for maintenance every Tuesday morning….
>
> Design of the « LWRFDO » was derived and inspired from many references
(including this list naturally).
> Principles are summarized in the attached pdf, with the following
specific feature to get rid of the phase modulation:
> The incoming signal

Re: [time-nuts] HP5065a cfield issue

2020-12-03 Thread djl

Paul:  You can have some fun with this:
A vertical line  current flow in the neighborhood of 30,000 amperes, 
pulse risetime on the order of 2-5 microsec, fall time about 40. Kind of 
a giant magnetic play toy.

Don Latham

On 2020-12-03 11:23, paul swed wrote:
Well Bob what an unusual comment about large magnetic fields. It just 
so

happens that maybe I actually had one about 8 weeks ago. Its called a
lightning strike about 60' away. Just found the actual 100' pine tree 2
days ago. I had been looking but it sounded like it hit in the opposite
direction.
The strike did wipe out a nvr and copper networking. But it did not 
seem to

impact the the cesiums or many many other pieces of equipment.
The 5065 is still super stable.
Regards
Paul

On Thu, Dec 3, 2020 at 11:57 AM Bob kb8tq  wrote:

Hi

I don’t believe that the quantum transitions are sensitive enough to 
minor

temperature
shifts to account for a 1 or 2 ppb sort of shift…..  Magnetic field, (
giant magnetic play toy
moved next to Rb … )  yes that will do the trick, but temperature … 
tough

to do …

Everything I can find that documents what’s what is behind this or 
that

pay wall. I’m
not $80 interested enough in the answer :)

Bob

> On Dec 3, 2020, at 10:51 AM, Poul-Henning Kamp 
wrote:
>
> 
>
> Could it be the thermostat circuits have shifted so you run at a
> different temperature now ?
>
> --
> 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.
>
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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

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Re: [time-nuts] 5370B / TimeLab question

2020-12-02 Thread djl


or:
https://ntrs.nasa.gov/citations/19870019361
from Charlie Greenhall

On 2020-12-01 15:52, Tom Van Baak wrote:

Hi Skip,

You are exactly right. And, surprisingly, this is correct and normal
for most TI counters.

The short answer is -- for your use case, a *zero deadtime* time
interval counter (TIC) or a timestamping counter (TSC), is what you
want.



The long answer is -- your problems is due to counter dead time. That
is, in TI mode, the counter waits for chA, and then waits for chB, and
then calculates and reports the chB-chA time interval measurement. The
latter takes finite time and depending on the counter it may consume
milliseconds or even tens of milliseconds. Part of it is CPU time,
part of it is I/O time (GPIB, RS232/USB, even LAN takes time).

So as chB drifts far away from chA, the next chA may occur during the
short busy measurement report window while the counter is "blind". The
counter then has to wait for the *next* next chA and this results in a
reduction in measurement rate from exactly 10 sps to exactly 5 sps.
Annoying as it is, it's actually a nice way to measure the counter's
deadtime ;-)

Note that this problem occurs with any TI measurement, but it is much
worse with a DMTD, so that's why you ran into already! If you were to
compare a OCXO/1PPS against a GPS/1PPS you might have to wait *years*
before a 1 s phase wrap, a counter deadtime issue, occurred.

You see, a DMTD is a huge magnifier. The good news is that it
magnifies phase difference and magnifies short-term instability by a
factor of, say, 500,000. The bad news is that it also magnifies phase
wrapping by 500,000. So instead of having an annoying 1 s phase wrap
every couple of years, or even once a lifetime, you're going to see it
happen every couple of hours



Ok, that said, one solution to this mess is to use a timestamping
counter (TSC) instead of a time interval counter (TIC). Yes, your
TAPR/TICC will work perfectly for this. In fact, this is the main
reason that the TICC was designed to be a flexible dual, independent,
simultaneous, zero-deadtime, chA-*and*-chB timestamping counter
instead of a traditional hardcoded chA-*to*-chB time interval counter.

Another solution is to use a microcontroller-based timer that can do
multi-channel timestamp captures. I have used synchronized picPET's
for this in the past. But more recently, for Corby's new DMTD, I
created a six channel timer that can do timestamping or *zero
deadtime* time interval measurements. Right now this solution works
better than a 5370B or 53132A at 1/100th the price.

Still, if you have a TAPR/TICC use that instead of your 5370B.

/tvb


On 12/1/2020 12:04 PM, Skip Withrow wrote:

Hello Time-Nuts,
I have been having fun playing with the DMTD, but have a question
regarding data collection.

Obviously with a 10Hz offset oscillator I am feeding square waves with
a 100ms period to the START and STOP of the 5370B.  The trigger lights
are happily blinking away at 10Hz.  However, I seem to have two
different operating modes depending on the difference between the
START and STOP signals.

If the difference is small, no problem.  I get 10 samples per second
when TimeLab is run (TimeLab puts the 5370B in Talk Only mode, I
believe).  When the difference between START and STOP approaches
something larger than 50ms I start getting only 5 samples per second.
  I believe this is because the re-arm time misses the next START 
edge,

such that I get every other sample.

This definitely gives bad data for TimeLab.  So, the question is, how
do I straighten out this mess?  For long-term measurements with two
oscillators that have any kind offset/aging difference you are toast.
I have thought about maybe adding a 10Hz EXT ARM signal, but if it is
not at exactly the 10Hz difference frequency that could create
problems too (and it is a pain in the butt).

I would like to use the 5370B, but maybe it's time to switch to the 
TICC.


Any suggestions would be appreciated.

Thanks,
Skip Withrow

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Re: [time-nuts] Is there a good web page introducing ADEV?

2020-10-12 Thread djl


attaboy for Attila. Reality always strikes.

On 2020-10-12 03:07, Attila Kinali wrote:

On Thu, 24 Sep 2020 13:11:26 -0700
"Richard (Rick) Karlquist"  wrote:


1.  The statistics of clocks are (take your pick)

a.  Not gaussian, central limit theorem doesn't apply
b.  Not stochastic
c.  Not stationary
d.  Not ergodic
e.  Contain flicker of frequency processes that do not
average to zero; AKA 1/f noise.


There is a small thing I like to add here: We all fool ourselves when
we look at ADEV.
Ok, that's slightly bigger than small, but let me explain.

Looking at noise processes in different frequency sources, one can 
identify

two regions:
1) a close in region where the dominant noise's origin is intrinsic to
the system and
normal/Gauss distributed
2) a far out region, where the dominant "noise" is mediated through 
changes in
the environment or the aparatus itself, which is decidedly not 
Gaussian.


For the close in region, our statistical tools (*DEV) do work and
deliver the answers
that we were looking for. For the far out region, the assumptions of
our tools fail
and we are basically tricking ourselves that we understand what's going 
on.


Let me first go in into the far out noise as this has a more intuitive
explanation:
The main contributors to this noise are temperature, air pressure, air 
humidity,

vibration (a quiet office building has 0.1g to 1g of acceleration
above 100Hz, constantly)
for the environmental noises and chemical absorption/desorption,
material creep/deformation
(including stress relaxation), and general aging of components, both 
electronic

and mechanical for the aparatus changes.

It is easy to tell that (almost) none of the effects above can have a
Gaussian distribution
(would either need something inherently Gaussian or averaging over
many non-Gaussian events).
E.g., temperature has a distinct periodicity at different frequencies
(daily, seasonal, etc).
Even the amount of vibration in a building has a diurnal and seasonal
varation, due to
how many people are active in and around the building. For some of
these, approximating
them by a Gaussian source is ok (e.g. steady state
absorption/desorption in equilibrium),
as they are close to being Gaussian already, for others only after the
main trend has been
removed (e.g. temperature after daily/seasonal variation removed). It
still does not make
the math correct, it just makes it a good enough approximation. A word
of caution here:
while removal of trends can make effects behave like Gaussian noise,
this has to be
checked. Especially for long running measurements, where the removal
might not be as
good as it might seem.

It is not hard to see, why our statistical tools fail for these types 
of noises,
when the processes we are looking at are not Gaussian. And this is why 
we fool
ourselves when looking at ADEV, as ADEV assumes Gaussian distribution 
in its

machinery, which is not the case for these types of noises.


Now to the hard part: the intrinsic noises.
The source of these noises are usually either from the "thing"
measured or by the electronics
used to measure. E.g. a quartz crystal has thermal noise that feeds
its white and 1/f noise
processes, it also has phonon scattering due to crystal defects that
again lead to white
and 1/f noise. An active hydrogen maser detects the low power emission
of the hydrogen atoms
in the cavity (a few to a few 100s of pW of power, IIRC), so the noise
of the detector
circuit is quite substantial.

On a high level view, these noises seem to fall into two categories:
white noise and 1/f noise.
Both are Gaussian, meaning, if you would take many atomic clocks,
start them at the same
time with zero phase offset, let them run for some time, measure the
phase differn and
check the sample distribution, you would get a Gaussian bell shape.
The difference
between the two is their correlation in time: While white noise has no
corrlation
in time (often abreviated with i.i.d. = identically independent 
distributed),
1/f noise has a 1/sqrt(t) decaying correlation in time. It is this 
correlation
in time, that makes things like mean and variance fail for 1/f noise, 
because it

breaks two other assumption we often make: stationarity and
ergodicity. Ergodicity
breaks because we have a non-stationary noise process. And 1/f noise
is non-stationary
because the expected value of the process is not independent of time
(very short:
the expected value for any future point of an 1/f process, is the last
sampled value).

You might have noticed that I have written only of two types of noise,
white and 1/f
and left out all other noise processes 1/f^a with an exponent a > 1.
The reason for
this is, because I think they are "not real". I have no proof for
this, but my conjecture
from looking at many publications and too much data is, that only
white and 1/f noise
are actually physical processes and 1/f^a processes come into
existence because we are
integrating in some way or other over a white or 1/f noise process.

Re: [time-nuts] distribution amps for 200 MHz

2020-09-15 Thread djl


Cheap Chinese rf amps ebay, also TV splitters

On 2020-09-15 12:17, jimlux wrote:

For work, I'm looking to distribute 200 MHz to 44 widgets..
The usual SRS, etc. boxes max out at 100 MHz.  Any ideas

(The going in position is "buy a bunch of minicircuits amps and
dividers and assemble it")

Tnx
Jim

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Re: [time-nuts] Chelsea Chronoquartz dividers

2020-09-11 Thread djl

Isn't the 4 MHz crystal near the sweet spot for one of the cuts? A dim 
memory at best :-)

DJ

On 2020-09-11 11:57, Tom Van Baak wrote:

Bill,

4194304 Hz = 2^22 Hz so 22 flip-flops gets you down to 1 Hz. The
binary divider is s similar to how the Seiko Beta 21 was designed. See
[1] for an example of a clock that uses this frequency.

What's nice about the Omega Ships Chronometer shown there is that it
has a LEMO 1PPS output so one can make precise measurements of the
clock without opening it and without resorting to audio, optical,
vibration, or magnetic methods. I have one here if you have any
questions about construction, repair, or performance (measured against
GPS).

/tvb

[1]
https://en.wikipedia.org/wiki/Omega_Marine_Chronometer#4.19_MHz_Ships_Marine_Chronometer


On 9/11/2020 10:30 AM, Bill S wrote:
A friend has acquired a Chelsea Clock Company Chronoquartz which was 
probably made in the 70's. He has measured the oscillator frequency at 
approximately 4.194304 MHz. He wanted to know what arrangement of 
dividers they used to run the 4 pole stepper motor to step seconds. 
Anybody know?


Thanks,

Bill_S

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Re: [time-nuts] Chelsea Chronoquartz dividers

2020-09-11 Thread djl


HINT: 2^22 = 4194304


On 2020-09-11 11:30, Bill S wrote:

A friend has acquired a Chelsea Clock Company Chronoquartz which was
probably made in the 70's. He has measured the oscillator frequency at
approximately 4.194304 MHz. He wanted to know what arrangement of
dividers they used to run the 4 pole stepper motor to step seconds.
Anybody know?

Thanks,

Bill_S

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Re: [time-nuts] Time Interval Counter(?) for high-precision watch measurement

2020-09-08 Thread djl

Sort of eavesdropping... you might try a piezoelectric pickup, available 
cheap on epay for guitars, etc. Looking at the actual motion kick of the 
hand(s)?

Don

On 2020-09-08 11:59, Raven L wrote:

Hi Bob, thanks very much for all the info!

You're right that my input signal is pretty crummy - if anything you
overestimate it. Eyeballing it on the scope, the edge is not 
particularly
defined at all - resolution better than a couple of microseconds just 
isn't
possible. I've typically used gate times in the 10^4 to 10^5 seconds 
range
(though typically collecting a measurement each second and doing the 
gating

myself in software, as modern watches have multi-millisecond phenomenon
that are interesting to study in the 1 to 100 second range).  I have 
tried
picking up electrical signals from the actual contacts going from the 
IC to
the motor, but even then the cleaner edge I got wasn't worth the 
trouble.

I took an initial pass through the manuals of the models you mentioned, 
I

really appreciate the guidance. (and the well-deserved correction on 2g
tipover for AT crystals - I'm not sure what I was thinking when I wrote
that but my notes confirm I was way off). I do hope to move up to a 
basic
home lab running off CSAC and Rb standards in the next few years once 
I've
seen all there is to see in wristwatches, but it looks like I have a 
lot to

digest.

One question if you know the answer on these 53131 and family models - 
the
manual mentions that RS232 is talk-only to a printer. Are there 
reasonable
tools out there for emulating a printer on a computer to pick up the 
data?

Otherwise it looks like I would need to set up GPIB.

On Tue, Sep 8, 2020, 1:12 PM Bob kb8tq  wrote:

Hi

First off, 0.001 seconds per year is ~ 3x10^-11. If you are talking 
about

the 2G tip effect on a typical AT cut crystal that’s up around 2 ppb.

Next up, low frequency / small package crystals are (inevitably) 
relatively

low Q devices. Low Q degrades ADEV performance / increases noise. If
you *could* measure a high Q device to 3x10^-11 in one second, it’s a
good bet that a low Q device will take 10X to 100X that amount of 
time.

The stepper motor in a watch is a low frequency inductive device. The
waveform out of it has a (very) limited bandwidth. Again another 
factor

that
will stretch out the time involved in the measurement. Your pickup 
coil

likely
also has some issues. ( That assumes the watch is still closed up. I 
would

not
recommend opening one up for testing …).

So far, none of this is looking at the frequency counter. We’re just
looking
at the device you are trying to measure.

Since there does not appear to be a need to get the data really 
quickly,
none of this is a show stopper. It simply suggests that something out 
in
the hundreds of seconds is likely to be the sort of gate time 
involved.

If you are after 3x10^-11 on a 100 second gate, that comes out to a 
rather

convenient 3 ns resolution. Better than that would be fine, but that’s
roughly
what you “need” to have.

There are lots of low cost counters out there that will hit that sort 
of

number.
The HP 5334 and HP 5335 both come to mind. They should be available 
for

< $200 (delivered). The TAPPR TIC would easily do the job for slightly
more.
The TIC probably would be easier to automate compared to running GPIB
on the 5334 or 5335.

Next step up would be something like a 53181 or 53131. They seem to 
start
out around $300 (delivered). You now have an RS-232 serial I/O and a 
device

that is about 10X better than your “need”.

These are only a very small sample of the vast number of counters out
there.
The only reason for picking them is that they all are devices I have 
used

a lot.
They all (with some effort) can be used to do what you are trying to 
do.

Fun !!!

Bob

> On Sep 7, 2020, at 6:23 PM, Raven L  wrote:
>
> Hello time nuts and greetings from the 10^-10 world of high precision
> wristwatches.
>
> I'm trying to set up a lab for automated watch measurement. I have a
basic
> GPSDO with a PPS and a 10MHz output. I use an inductive sensor to pick up
> the signal from the motor inside the watch.
>
> I've been using a basic digital oscilloscope to measure the interval
> between the PPS and the watch signal.  The signal from the watch has a
> total rise time of about 10us to 40us, varying by watch, and rises a few
> volts above a noise floor of about 50mV. The oscilloscope does a
> serviceable job but doesn't allow automated measurements and can't be
> driven by an external timebase. My goal is to make measurements with a
> precision of about 10us, with a goal of ultimately pinning down a rate to
> better than 0.001 seconds per year (initial testing shows this is what I
> need to resolve the effect of tipover on AT-cut MHz-range quartz
crystals).
>
> Are there specific time interval counters or frequency counters that
would
> make this easier?  I've been looking at the SR620 as a candidate, which
> appears to be available used for around

Re: [time-nuts] 3D printed tourbillon clock

2020-07-25 Thread djl

Ummm-- I watched the video. Start to finish. I noticed in many places
hand movements reminiscent of those I practiced many times in front of a
mirror. There is nothing up my sleeve...

Wonder how long plastic springs hold up?
Don

On 2020-07-25 12:42, Tom Van Baak wrote:
I’m guessing a couple hundred hours to print the parts and maybe the
same

sort of time to clean them all / fit them together …..

Bob,

Good guess. The video comments say 110 hours print time. Full details
below.

BTW, even if you don't watch the video, the 22 MB
"Tourbillon_Mechanica_Assembly_Guide.pdf" file is worth downloading
and admiring. The direct google drive link is below.

Now if we could just 3D print a OCXO, Rb, or Cs standard we'd have as
much fun as the mechanical clock guys. ;-)

/tvb

https://www.youtube.com/watch?v=E9prY3ky6Bo

Cool 3D Printed Mechanical Clock | Tourbillon Mechanica (FDM Version)
Assembly Guide

101,691 views Jul 13, 2020

Dan.T
8.52K subscribers

This is the FDM version of the Tourbillion Mechanica that is modified
to optimise
printability and assembly on a FDM printer. These was printed on the
standard Ender 3.

Detailed step by step assembly and printing guide can be downloaded
here:

https://drive.google.com/file/d/1JZ_KSSja-Vo8brJ3yLqM_bRg7YPXFP6R/view

Link to STL files:

https://www.myminifactory.com/object/3d-print-tourbillon-mechanica-tourbillon-escapement-mechanical-clock-assembly-guide-pdf-in-description-124938

Approximate run-time on PETG spring: 10 minutes
Total Print Time: 110 hours
Material Consumption: 350 grams

More details can be found in the detailed pdf guide!

On 7/25/2020 8:22 AM, Bob kb8tq wrote:

Very cool !!

I’m guessing a couple hundred hours to print the parts and maybe the
same

sort of time to clean them all / fit them together …..

Bob

On Jul 25, 2020, at 2:40 AM, Mark Sims wrote:

https://www.youtube.com/watch?v=E9prY3ky6Bo
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Re: [time-nuts] For those following ES100 WWVB receiver modules

2020-07-22 Thread djl


Is there a gnu radio receiver? Should be able to handle this speed.
Don

On 2020-07-22 11:41, Tim Shoppa wrote:
The ES100 module sold by universal-solder.ca which Tom introduced us to 
a

couple years ago,  is now End-Of-Life. "A new module is currently in
development".

https://www.universal-solder.ca/product/everset-es100-cob-wwvb-60khz-bpsk-receiver-kit-with-2-antennas/


I myself did some experimenting with a tuned loop antenna through a 60 
kHz
crystal bandpass hooked to a 192k sample rate USB audio card. I can 
post

process data to pull out phase shifts and time code but am nowhere near
doing this in real-time.

Tim N3QE
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[time-nuts] oddball frequencies

2020-05-19 Thread djl


another cost-effective solution:
https://www.sv1afn.com/en/products/adf4351-pll-synthesizer-module.html

Don

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[time-nuts] One of the best demos/explanations I've ever seen re sampling.

2020-05-19 Thread djl




HEY!!! I know many of us "know" this, but I found the refresher 
refreshing!  A really good explanation of sampling. Especially why 
simple decimation doesn't work.

https://zigunov.com/2020/04/25/the-anti-gravity-spout-a-demonstration-of-aliasing/
Don
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Re: [time-nuts] Arrows of Time: A project by Quanta Magazine

2020-05-12 Thread djl

And Dicke was done out of a Nobel because his antenna was too small. 
He's the one who told P what they were measuring. That is, after the 
pigeon poop had been cleaned out of the horn...

D
On 2020-05-12 16:22, Tom Van Baak wrote:

The following article just came out. It's not deep, but it's a quick,
readable overview that you can share with friends that wonder why
timekeeping is so interesting. I agree with reader comments that John
"Longitude" Harrison was a major omission.

"Arrows of Time: A project by Quanta Magazine"
https://www.quantamagazine.org/what-is-time-a-history-of-physics-biology-clocks-and-culture-20200504/

/tvb


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[time-nuts] splitter

2020-05-10 Thread djl


https://www.sv1afn.com/en/gnss-gps/-7.html
a medium price 4-way
Don

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[time-nuts] Fwd: [New post] Sun-Seeking Sundial Self-Calibrates in No Time

2020-05-06 Thread djl

 

for fun 

 Original Message  

SUBJECT:
[New post] Sun-Seeking Sundial Self-Calibrates in No Time

DATE:
2020-05-06 14:01

FROM:
Hackaday 

TO:
d...@montana.com

 Kristina Panos posted: "Sundials, one of humanity's oldest ways of
telling time, are typically permanent installations. The very good
reason for this is that telling time by the sun with any degree of
accuracy requires two-dimensional calibration -- once for cardinal
direction, " 

NEW POST ON HACKADAY

SUN-SEEKING SUNDIAL SELF-CALIBRATES IN NO TIME [1]

 by Kristina Panos [2] 

Sundials, one of humanity's oldest ways of telling time, are typically
permanent installations. The very good reason for this is that telling
time by the sun with any degree of accuracy requires two-dimensional
calibration -- once for cardinal direction, and the other for local
latitude. 

[poblocki1982] is an amateur astronomer and semi-professional sundial
enthusiast who took the time to make a self-calibrating equatorial 'dial
that can be used anywhere the sun shines [3]. All this solar beauty
needs is a level surface and a few seconds to find its bearings. 

Switch it on, set it down, and the sundial spins around on a
continuous-rotation servo until the HMC5883L compass module finds the
north-south orientation. Then the GPS module determines the latitude,
and a 180° servo pans the plate until it finds the ideal position.
Everything is controlled with an Arduino Nano and runs on a 9V battery,
although we'd love to see it run on solar power someday. Or would that
be flying too close to the sun? Check out how fast this thing calibrates
itself in the short demo after the break. 

Not quite portable enough for you? Here's a reverse sundial you wear on
your wrist [4]. 

KRISTINA PANOS [2] | May 6, 2020 at 1:00 pm | URL:
https://wp.me/paBn4l-1IXQ 

Comment [5]
   See all comments [6]

Unsubscribe [7] to no longer receive posts from Hackaday.
Change your email settings at Manage Subscriptions [8]. 

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Links:
--
[1]
https://hackaday.com/2020/05/06/sun-seeking-sundial-self-calibrates-in-no-time/
[2] https://hackaday.com/?author=37213840
[3] http://www.instructables.com/id/Self-Calibrating-Sundial/
[4]
https://hackaday.com/2017/07/27/tell-time-with-a-reverse-sundial-watch/
[5]
https://hackaday.com/2020/05/06/sun-seeking-sundial-self-calibrates-in-no-time/#respond
[6]
https://hackaday.com/2020/05/06/sun-seeking-sundial-self-calibrates-in-no-time/#comments
[7]
https://public-api.wordpress.com/bar/?stat=groovemails-eventsbin=wpcom_email_clickredirect_to=https%3A%2F%2Fsubscribe.wordpress.com%2F%3Fkey%3Dd109931f8119f9f47c8f2ccdf1639bbf%26email%3Ddjl%2540montana.com%26b%3DpyeE6emrnTuFfOk35B6kXVdiSTHEjcWXqxhcgfDt1TKC_lWCaLs8cWTfNShbQdkY4OjvqBoYYQevPWRe7dygICvlCcze6pZh1YLH-d3avD2wOig%253Dsr=1signature=9030c6b42ce26b79007a1ffce6dc6135user=b74863dc25f865bb6e7b9e41a608caed_e=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
FtcD0xNTg4Nzk1MjMxLjcwNDMmcXVldWU9c3luYyZob21lPWh0dHBzJTNBJTJGJTJGaGFja2FkYXkuY29tJnNpdGV1cmw9aHR0cHMlM0ElMkYlMkZoYWNrYWRheS5jb20mY2Q9MC4wMDI3JnBkPTAuMDA0MSZxdWV1ZV9zaXplPTImaWRjPTEmdGltZW91dD0xNSZmb3I9amV0cGFjayZ3cGNvbV9ibG9nX2lkPTE1NjY3MDE3NyIsIl9lbiI6IndwY29tX2VtYWlsX2NsaWNrIiwiX3RzIjoxNTg4Nzk1MjYxMzMxLCJicm93c2VyX3R5cGUiOiJwaHAtYWdlbnQiLCJfYXVhIjoid3Bjb20tdHJhY2tzLWNsaWVudC12MC4zIiwiX3VsIjpudWxsLCJibG9nX3R6IjoiLTciLCJ1c2VyX2xhbmciOm51bGx9_z=z
[8]

Re: [time-nuts] LightSquared is back now called Ligado

2020-04-17 Thread djl

And the competition has/is putting up a gazillion cubesats to screw up
another of my little pleasures, astronomy. Bah. It's enough to make you
want to go out and stand right next to somebody.

Don

On 2020-04-17 14:37, Scott McGrath wrote:

That was +9.8 on the terrrestrial microcell transmitters,

Yes this seems to have been sold with the assurance that the magic
brickwall filters with 100db/octave slope will be included in every
one.

But the asian manufacturer of said devices will neglect to include
them and juice the power a wee bit to say +23...

Of course this will hose every GPS system for miles around and for
those of us who fly our multi thousand investment in ADS-B will be
rendered useless as the ADS-B still uses L1.In our club’s Cessna
172 the new ADS-B in/out compliant radio stack was 20,000 as we are
close to a lot of controlled airspace.

I dropped a note to AOPA on this. Because remember the entire
airway system is now supposed to be managed by aircraft exchanging
position, bearing altitude and rate of climb dynamically to each other
and ground stations instead of todays radar based system.

And say goodbye to our GPSDO’s

On Apr 17, 2020, at 2:59 PM, Bob kb8tq wrote:

Was that +9.8 or -98 dbm ? :)

At -98 they probably *could* coexist with GPS. Not real clear how well
there

system would work at that level though.

Bob

On Apr 17, 2020, at 1:37 PM, Scott McGrath
wrote:

Supposedly lowering Tx power on terrestrial network from +23 DBm to
+9.8 DBm will make everything better. Ajit Pai is listening only to
carriers and ignoring DoD who is stating it will significantly degrade
and/or make useless the GPS system.

Not to mention ADS-B which was installed at great expense by the
private and commercial aviation systems. And is totally dependent on
the GPS segments most affected by Ligado

Read and weep

https://arstechnica.com/tech-policy/2020/04/fcc-to-approve-5g-network-despite-military-saying-it-will-harm-gps/

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Re: [time-nuts] LightSquared is back now called Ligado

2020-04-17 Thread djl


It's all about imaginary brick wall bandpass filters.


On 2020-04-17 11:37, Scott McGrath wrote:

Supposedly lowering Tx power on terrestrial network from +23 DBm to
+9.8 DBm will make everything better.  Ajit Pai is listening only to
carriers and ignoring DoD who is stating it will significantly degrade
and/or make useless the GPS system.

 Not to mention ADS-B which was installed at great expense by the
private and commercial aviation systems. And is totally dependent on
the GPS segments most affected by Ligado

Read and weep

https://arstechnica.com/tech-policy/2020/04/fcc-to-approve-5g-network-despite-military-saying-it-will-harm-gps/


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Re: [time-nuts] Ultra Stable Rb

2020-04-09 Thread djl

Very nice experiment. What do you think might be affected by pressure? 
At least in the physics pkg?

Don

On 2020-04-09 09:36, Skip Withrow wrote:

Hello Time-Nuts,
This is a subject that I have been interested in for quite some time.

If you do some searching on Rb oscillator aging, there is a paper from
FEI that showed GPS units aging in vacuum  (and space) differently (as
in opposite sign) than at sea level.  My thought was that there should
be a pressure where the aging should go to zero.

I have been told by several people (that should know) that this has
been studied in the industry and has never come to anything.

But I'm a sucker for punishment.  In April of 2018 I acquired a very
nice vacuum chamber surplus from the aerospace industry.  I
contemplated which Rb oscillator to use and finally decided on the
LPRO-101 since it had no DDS (and thus no discrete steps) and a wide
supply voltage range (and I had several of them).  The unit was
mounted to the heavy aluminum lid of the chamber (which had five
61-pin electrical feedthru connectors, so no problem there).  Kapton
heaters were applied to the outside of the chamber and connected to a
temperature controller, and a low noise power supply that could be
varied from 18-32 volts was used to power the LPRO.  A modified NTBW50
is used to monitor the output of the LPRO.  A UPS and line conditioner
were also added to the system.

I did not want to  drive the EFC (to remove a many variables as
possible).  The C-field was set to get the unit about on frequency at
around 20Torr, then the supply voltage was tweaked to put it exactly
on frequency.

I have found that, indeed, the aging direction can be changed with
pressure.  And there is a pressure that you can get the drift to zero.
However, another fly in the ointment is that changing the supply
voltage to put the unit on frequency also changes the aging.

At this point (Jan 2019) I connected the NTBW EFC drive to the LPRO.
Now the LPRO could be disciplined, but as we all know GPS degrades the
short-term performance.  So, I run the unit with discipline disabled
and just manually change the DAC voltage to keep the LPRO on
frequency.  The supply voltage, chamber pressure, and chamber
temperature have not been touched since that point.  By knowing the
EFC gain I can calculate the aging.

For the 238 day period ending 3Nov19 the aging was -3.76x10E-14 /day.
Not bad as far as Rb goes, but I can certainly do better.

The next step I would like to take is to move the C-field adjustment
outside the chamber (and increase its resolution) so that I can put
the oscillator on frequency without any changes in supply voltage.
And again disconnect the EFC (since there is a temperature dependence
on the DAC value).  Then I should be able to get back to finding the
exact pressure the chamber should be set at.

The whole system is contained in a very short rack with the chamber on
top of it and an insulation shield over it.  I call it RUFUS (RUbidium
Frequency Ultra Stable).  It lives underneath the stairs going to the
basement.

I have also considered just building a box to drive the EFC and
increment the voltage at the proper rate for whatever the drift might
be for the temperature, pressure, and supply voltage that the
oscillator might be at.  Too much fun!

Sorry for the long post.  I'm hoping to have a detailed paper with all
the details at some point, but getting all the data of course goes
very slow.

Regards,
Skip Withrow

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Re: [time-nuts] Ultra Stable Rb

2020-04-08 Thread djl

So it's Chinese engineering? Find something good that works, start 
removing parts until it doesn't, put in the part last removed, and sell 
it?


My granddad worked for a guy in LA called Madman Muntz who made tv's 
that way in the late 1940's. They worked. Sorta. For a while. If the 
signal was strong enough.

Voila! $X-$400

On 2020-04-08 13:51, Bob kb8tq wrote:

Hi

At the time EG had done the GPS Rb’s but not done any other
military parts. Some research showed that indeed the FRK went into
a variety of systems and the price was $X. (It varied a bit with 
quantity)


Push the numbers around and look at this and that. The decision was 
made
that indeed if you could sell a few hundred to maybe a thousand a year 
at
$X, it was a good thing. A design was done and (as noted earlier) it 
was

a good little device.

The fun part came with that $X pricing. Out comes a request for some 
few
hundred pieces to this or that organization. Bid $X, order goes down to 
the
competition for X-$300. Next request for a few hundred, bid X-$400, 
order
goes down to the other guy for X-$500. This step by step process goes 
on

for a year …. same result again and again.

At the end of that time period it was far less clear just *why* one 
does up

an FRK like part ….

Bob


On Apr 8, 2020, at 2:32 PM, djl  wrote:

What a tease! OK, very well WHY???
Don

On 2020-04-08 08:04, Bob kb8tq wrote:

Hi
A few of the long running FRK’s ( in a very similar package …
hmmm ….. wonder why …. yes, I was there way back then
and know very well why :) ) have crazy good long term aging.
That said, I don’t think that I’ve seen a FRK quite this good.
Thanks for sharing !!!
Bob

On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
Hi Guys,
Just though you'd be interested in my prototype rubidium frequency 
standard

I made in the 1990's.
http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
I have measured its frequency at random intervals for the past 18 
years.

Its never been adjusted and is just free running.
It was turned off in 2005 and sent to a customer in Japan for a few 
weeks,

then returned and turned back on.
For the past 18 years its stayed within plus/minus 3 x 10E-11.
The overall linear drift is something like 1.85 x 10E-13 per month.
This is not an advert.  There's no way any of our production units 
are as
good as this one, well I assume so as I've never measured any for 18 
years

continuous!
Its now over 25 years old, have hardly ever been turned off.  Any 
day I

expect it to fail, but it keeps on running!!
Regards
Martyn
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Re: [time-nuts] Ultra Stable Rb

2020-04-08 Thread djl


What a tease! OK, very well WHY???
Don

On 2020-04-08 08:04, Bob kb8tq wrote:

Hi

A few of the long running FRK’s ( in a very similar package …
hmmm ….. wonder why …. yes, I was there way back then
and know very well why :) ) have crazy good long term aging.
That said, I don’t think that I’ve seen a FRK quite this good.

Thanks for sharing !!!

Bob


On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:

Hi Guys,

Just though you'd be interested in my prototype rubidium frequency 
standard

I made in the 1990's.

http://www.ptsyst.com/RFS10-FrequencyDrift.pdf

I have measured its frequency at random intervals for the past 18 
years.


Its never been adjusted and is just free running.

It was turned off in 2005 and sent to a customer in Japan for a few 
weeks,

then returned and turned back on.

For the past 18 years its stayed within plus/minus 3 x 10E-11.

The overall linear drift is something like 1.85 x 10E-13 per month.

This is not an advert.  There's no way any of our production units are 
as
good as this one, well I assume so as I've never measured any for 18 
years

continuous!

Its now over 25 years old, have hardly ever been turned off.  Any day 
I

expect it to fail, but it keeps on running!!

Regards

Martyn


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[time-nuts] Symmetricom analog network clocks.

2020-03-24 Thread djl

Some years ago, symmetricom sold out some analog network clocks. Last 
winter, both of mine froze up and would not adjust. Being naturally 
curious, I opened one up, and found the motor and wheels that drive the 
hands. Knowing that this type of motor has problems, I simply unplugged 
it and manually forced the going train and the motor on each clock to 
turn in both directions(use your thumb.) After all, it was no good as 
is. I guess the grease was redistributed, as both clocks now function 
properly. They do have to be set using the software sort of often, but 
sure look classy :-). No wonder we got them so cheap!

73, Don

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[time-nuts] of possible interest

2020-03-20 Thread djl




https://www.sv1afn.com/en/products/vhf-uhf-triplexer-1.html

10 mhz and uhf/vhf on same cable.
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Re: [time-nuts] Trueposition behavior

2020-03-10 Thread djl


Is this effectively dither on the control voltage?

On 2020-03-10 10:30, Skip Withrow wrote:

Hello Time-Nuts,
A couple of weeks ago I posted regarding some weird behavior of the
Trueposition GPSDO that I was seeing.  I have now been able to get
back to the problem and have further results to report.

I have several of these GPSDOs that are version 12.0.1 (I believe the
latest is 12.1.1) and they all seem to behave the same.

I have attached two Lady Heather plots.  One is the GPSDO output of
the control voltage, the other is the 10MHz output monitored by
another NTBW GPSDO.  The bumps in the control voltage are what was
bothering me.

It appears that the way this GPSDO operates is to let the oscillator
free run until there is 50ns of accumulated time error (LH reports
'Normal' during this phase),  Then it goes into control mode, you can
see more noise on the DAC signal during this time plus the big spike,
and yanks the phase back to zero (LH reports 'Acquiring' during this
phase).

The unit must model the OCXO drift as the DAC does change during the
drift period.  So, the longer the unit runs the longer between upsets
(hopefully).  These plots were taken shortly after start up, I am in
the process of letting it run for a while now.  BTW, the very periodic
dropping and acquisition of the WAAS bird (PRN138) is still present.

This behavior is a good news/bad news situation.  On one hand, during
the drift period the output of the GPSDO is not influenced by GPS and
getting yanked around second by second (like the Thunderbolt).  On the
other hand, if the 50ns yank happens when you are making a measurement
it kind of trashes things.  I haven't tried seeing if LH can disable
disciplining (for use during measurement periods).

Regards,
Skip Withrow

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Re: [time-nuts] Help with BG7TBL 2015-07-08 GPSDO

2020-02-01 Thread djl


Are they both "real" RS-232, both 5v ttl rs232, or hopelessly mixed?

On 2020-02-01 15:18, Gary Woods wrote:

On Sat, 1 Feb 2020 12:24:24 -0600, you wrote:


Hmmm. I do not have any of that equipment, but I do know the RS232
interface pretty well. It may be that you need to cross over the
connections with RX and TX. Do you have a null modem type device 
handy?

The GPSDO says it only needs send and receive data; no handshake. I've
got a break-out adapter in the line passing only those and ground.
Reversing t/r doesn't help.
Gonna scope the interface chip's ins/outs, but right now the cellar
hamshack/shop/man cave is just too (*^&*%* cold!

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Re: [time-nuts] Wall Clock that takes 1PPS input

2020-01-02 Thread djl

I recall using a clock like that. I drove the coil with a 5v cmos type D
flipflop. The coil is hooked to q and ~q with a couple of resistors.

That way you get the reversal of voltage with little fuss.
Don

On 2020-01-02 16:32, Jerry Hancock wrote:

I’ll have to go read about the Lord Vetinari clock. He is one of my
favorite book characters.

Thanks for all the tips. I might have an old quartz clock around here
to test. I assume I can just measure the pulse while it is running
and generate the same with the 1PPS output. I’ll have to program a
way to advance it, maybe use an Arduino or some other micro and add a
few switches.

On Jan 2, 2020, at 12:43 PM, Philip Gladstone
wrote:

It depends on how much work you want to do. I have various clocks
driven
off 1PPS (or 2PPS) signals. The cheapest approach is to take almost
any
quartz clock with a second hand and drive the coil directly (you need
to
pulse with alternate polarities -- i.e. there are even and odd
pulses).

I was introduced to this technique by building a Lord Vetinari clock
(e.g.

https://www.instructables.com/id/Lord-Vetinari-Clock/ )

I purchased something like
https://www.ebay.com/itm/8-5-INCH-KAPPA-SHIPS-BOAT-YACHT-MARINE-RADIO-ROOM-SLAVE-NAVIGATION-CLOCK/143072681993?hash=item214fcbe009:g:Gn8AAOSwYTtcKPIp
and
it turned out to be a 2PPS clock

Fun getting this stuff working!

On Thu, Jan 2, 2020 at 3:32 PM Jerry Hancock wrote:

Hello,

I looked around but can’t find a wall clock that would take a 1PPS
input
signal to drive the minutes and seconds. I’ve made digital modules
using a
lot of different displays but would love to have a large, 14” or so
with a
second hand, wall clock that I can drive with 1PPS. The old IBM
clocks,
etc I found take a pulse on the minute. I have an old pendulum clock
I can
drive with a solenoid but thought I would ask here before going that
route.

Signal levels aren’t important.

Thanks

Jerry

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je...@hanler.com

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Re: [time-nuts] 1 pps Accuracy in two locations

2019-12-04 Thread djl

Maybe Grace Hopper's aid will help? 11.8 inches = one nanosec, so a ps 
is .0118 inches. You really want two clocks not occupying the same space 
to be correlated to that accuracy?

Don

On 2019-12-04 08:55, Tom Van Baak wrote:

Martyn,


I'm always being asked to provide equipment that can produce two 1
pps outputs aligned to each other to within a few ps.


They should look at their best 1PPS on a 'scope. You can get ns with
care; I doubt ps is possible. I mean, that's THz BW isn't it?

Can you share with us what their application is?



So they are asking for two of my GNSS frequency standards with 1 pps
outputs.

The 1 pps outputs being derived from the rubidium oscillator (which
is aligned to GPS/GNSS)

The best I think I can achieve is in the low ns range.


Right. It will be ns, not ps. Forget about using GNSS for ps level 
timing.




Does anyone know how this can be achieved?


Google for papers by high-end national timing laboratories. Words
like: active temperature stabilized (phase stabilized) bidirectional
optical fiber links.

Very possible, very expensive, quite common now. I'd guess most of the
timing centers in Europe are linked this way.

/tvb




On 12/4/2019 1:40 AM, mar...@ptsyst.com wrote:

Hello,

  I'm always being asked to provide equipment that can produce two 1 
pps

outputs aligned to each other to within a few ps.

  These two 1 pps pulses are not in the same location and could be 100 
metres

to a few km away.

  So they are asking for two of my GNSS frequency standards with 1 pps
outputs.

  The 1 pps outputs being derived from the rubidium oscillator (which 
is

aligned to GPS/GNSS)

  The best I think I can achieve is in the low ns range.

  Does anyone know how this can be achieved?

  Regards

  Martyn

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Re: [time-nuts] FA-2 questions

2019-10-14 Thread djl

I agree completely. A friend and I each had one of these and thought 
there was something wrong with each of them. The dither at 10 MHZ 
compared to a gpsdo is approximately 10 Hz. We spent many hours with the 
manual trying to find the cause of the fm to no avail. It's just a bad 
design. Unsuitable for any time-nuts use. Maybe OK for fixing pre-sdr 
ham radios. The attenuator section is pretty good. Otherwise in today's 
world a boat anchor.

Don

On 2019-10-14 16:57, Didier Juges wrote:
HP8656 and spectral purity should not be used in the same sentence. I 
had
one and the best band is VHF where it may be usable for SSB or NBFM if 
you

are not too picky. It gets worse from there going up. The worst is the
lower band (HF) because it is actually the high band mixed down.

http://www.ko4bb.com/getsimple/index.php?id=comparing-the-hp-8656a-hp-8657b-and-hp-3586a

Didier KO4BB

On Sat, Oct 12, 2019 at 10:07 PM David  wrote:

The hp8656 spectral purity may be a problem.  Residual FM for output
frequencies above 494MHz is < 15 Hz rms ( 0.3 to 3 kHz BW ).  (The B
version is better by about a factor of 2)
Dave

Perry Sandeen via time-nuts  wrote:

>Yo Bubba Dudes!,
>First, does the internal OCXO run when the power is turned off?
>Wrote:
>We are presently experimenting using a ISC570B  multiplier at 100 MHz
>and get 13 digits seeattached but the data out of the back is only 12
>digits reliable.
>Looking it up I found out that the ISC570B is a teeny - tiny IC which
>for me would pose a problem to implement.
>
>So looking at alternatives that I already had I came up with two
>possible alternative multiplier ideas.
>The first was to put the 10 MHz DUT into the external reference of my
>(boat anchor) HP signal generator set the output frequency to 200 MHz
>and put the output into the channel 1 input to get extra resolution
>digits.
>Expanding upon that, I came with more complex but what may be a better
>error multiplier reading since I have both signal generators on hand.
>First I feed the 10 MHz DUT signal into my Fluke 6080 setting the
>output to 1 GHz.  I'd then feed the reference 10 MHz signal into the
>external reference of my HP 8656 and set the output to 990 MHz.
>Next I'd feed both outputs into a
>AD8342 LF to 3.8GHZ Active Mixer Down conversion Output withBalun
>Transformer
>
>board from ebay ($23) and then feed the multiplied signal into channel
>1. (I may need a simple low pass filter.)
>
>
>This should give me a 100X error multiplication.
>
>
>Am I on the right track or am I missing something?
>
>
>Regards,
>Perrier
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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Sent with mySecureMail.
http://www.mysecurephone.eu/

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Re: [time-nuts] FA-2 Operator manual

2019-10-13 Thread djl

Didier has allowed .doc and .docx documents. I've uploaded Perrier's 
.docx so the set is complete.

Don
On 2019-10-12 16:33, Perry Sandeen via time-nuts wrote:

Yo Bubba Dudes!,
For those who may be interested, I D/L djl's FA-2 manual and revised
both pictures and text.
Don said he would post it for me on the KO4BB site as I haven't had
good luck uploading stuff.
Regards,
Perrier
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Re: [time-nuts] Question for my new GPSDO Heater

2019-10-13 Thread djl

Hello:  proportional controllers from the Old Country are also available 
for around $15 on ebay. The one i have uses type K thermocouple.

Don

On 2019-10-12 18:13, Perry Sandeen via time-nuts wrote:

Yo Bubba Dudes!,
The suggestion was made to use a ebay item number 192112054053 heater
for this project.
Now it's cheap and has a digital reading.
BUT
It is a bang- bang controller using a relay.  At some point that relay
will stop working.  Also all designs I've seen for good temperature
control use proportional solid state controllers.  There are plenty of
free designs on the internet.
Lastly, if one believes that this is long term reliable controller
that will deliver .1 degree accuracy, for that price, please contact
me off line and I will set you up with some really cheap (but slightly
scorched and a burned wood smell) lots to where you can build your
dream home here in California.
Regards,
Perrier



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Re: [time-nuts] Question for my new GPSDO

2019-10-08 Thread djl

Tobias: along the path suggested by TVb, might I suggest something like 
a small heater/cooler for your car?

lots at https://www.amazon.com/s?k=car+cooler+6+pak=nb_sb_noss
a simple controller such as

eBay item number:
192112054053
 can be applied as well.

and Bob's your uncle.
Don

On 2019-10-08 06:35, Tom Van Baak wrote:

Hi Tobias,

Very interesting project you have. Not just that it's a fresh GPSDO,
but interesting because you seem to be taking so much care in the
design. A couple of comments:

1) The need for ultra low tempco is more important if you expect your
GPSDO to be in holdover often; less so if it is permanently locked to
GPS.

One approach is to spend the money for low tempco devices and trust
them; another is to monitor the temperature and apply calibrated
corrections in s/w. I can't predict which is better, but don't
discount the latter approach.

Still, either method will have to be verified with actual experiment,
strip charts, correlation analysis, and ADEV plots. So I hope you have
the test equipment at hand to measure these subtle effects in a GPSDO.

2) I suspect one can spend a great deal of time picking and testing
optimal parts in a GPSDO based on tempco specs. But at what point is
it cheaper to just control the environment of the GPSDO board itself?

You mention opening lab doors and windows and such. Wouldn't it be
simpler to spent time to design a box that is wind-proof, or
fan-controlled; maybe even oven controlled? That way you can relax all
your worries about exotic passive and active components and just build
a controlled enclosure.

That could not only take care of temperature, but humidity and
pressure as well if they were found to be sources of instability. One
advantage of this approach is that the same box design could then be
applied to any other T projects like distribution amps or phase /
frequency counters that you design in the future.

3) About sensors.

many GPSDOs I have tested (e.g. Trimble Thunderbolt, STAR4) show info 
about the OCXO temperature


The Trimble Thunderbolt (TBolt) uses an onboard DS1620 temperature
sensor. I don't recall it ever being called "OCXO temperature"; it's
ambient board temperature. Perhaps because the board is inside a
larger aluminum enclosure the board temperature is related to OCXO
case temperature. But as far as I know the reported temperature value
from a TBolt is definitely not the temperature of the crystal
resonator itself.

/tvb


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[time-nuts] SR620 ocxo oscillator

2019-10-08 Thread djl

Looking for replacement for the ocxo oscillator in my SR620; old one 
drifted out of adjustment. SR suggested one of their SC10 oscillators 
which, at $500 a copy, ain't gonna happen.  I put a Morion in place, and 
it works, but has to be outboard because it runs too hot. So, a new 
cheapy from ebay (273823088054) on order.


But the sr10 spec sheet and user manual
https://www.thinksrs.com/downloads/pdfs/manuals/SC10m.pdf
 has a very nice explanation of their product including schematic and 
blow-by-blow description of how it works for those interested in design. 
The primary aim of the design is said to be excellent phase noise and 
low aging.


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Re: [time-nuts] DC distribution

2019-10-04 Thread djl

Long ago and far away, I did read that a large(60% or so) of failures in 
ww2 style equipment was due to wire breakage right at the terminal, that 
is solder wicking into stranded wire. The very careful wire wrap through 
holes or around terminals did nothing.  Power pole connectors do not 
have crimped insulation. Spade lug and rings very often do. Strain 
relief is a must, especially in presence of higher frequecy vibration. 
These facts are around, just cannot recall where.

Don

On 2019-10-04 14:41, Poul-Henning Kamp wrote:


In message <5d979ac0.80...@rogers.com>, MLewis writes:


With audio signals, a soldered crimp is one of the worst possible
connections.


Dabbling in audio-homoepathy are we ?

No, don't bother responding unless you have a reference to 
peer-reviewed

scientific documentation for you claim.


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[time-nuts] FA-2 manual

2019-10-02 Thread djl

Just did a rough edit of the FA-2 manual; downloaded to KO4BB. Just 
edited out the Chinese. The usb commands section is pretty rough, needs 
to be wrung out, no time just now.
Old MS Word compatibility format. The block diagram did not appear. I 
think, for the price, this is, as the Brits have it, a pretty good piece 
of kit.

Don

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[time-nuts] SR620 counter

2019-10-01 Thread djl




My sr620 counter has gone nuts. Completely blank readouts, both led's 
and numerals.
I have the manual. and all voltages post-regulator check out. I just 
wondered if there are known weak spots or idiosyncrasies? There is a 
clock dropout control that seems to be holding off the front panel. 
haven't got beyond that, except to note that no smoke seems to have been 
liberated anywhere.  UVROM???


Btw, thanks to all who responded to the chrony query. Gonna try it for a 
local server with an RPI and gpsdo hat from Adafruit.

Thanks again,
Don
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Re: [time-nuts] Even Seconds Pulse option (1PP2S), HP 58503B

2019-09-29 Thread djl

To replace one?

On 2019-09-29 10:22, paul swed wrote:

On second thought (Pun intended)
Its a pendulum clock output. Have no idea why some one would use a 
GPSDO to

drive a pendulum clock but that could be a reason for such a thing.
Paul

On Sun, Sep 29, 2019 at 12:02 PM Dana Whitlow  
wrote:

I can't speak for 1/2PPS, but at the Arecibo Observatory we 
distributed

1PPS with every
10th second's pulse stretched to about twice the duration of the 
others.  I

did find that to
be kind of handy every now and then, when troubleshooting things.

Dana

On Sun, Sep 29, 2019 at 8:36 AM Gregory Beat via time-nuts <
time-nuts@lists.febo.com> wrote:

> A new resident arrived at the “Time Cave” this weekend, the
HP/Symmetricom
> 58503B.  Just the plain front panel (4 LEDs) model, without Option 1 (VFD
> clock display).
> Acquired in USA, cheaper than current Asian exporter.
> https://accusrc.com/uploads/datasheets/4975_58503b.pdf
>
> Supposedly stored in a closet since 2010 (verified by its diagnostic
> logs), the unit only had 2,000 hours of operation.
> Today, it happily has a GPS Lock and is currently “re-learning” where the
> 1 PPS and 10 MHz outputs wandered (taming Lazarus).
> —
> One surprise, it has Option 2 (1PP2S) installed on its Rear Panel.
>
> Option 002 : 1 PP2S (One-Pulse-Per-Two-Seconds) connector for outputting
a
> pulse every other second, synchronized to the even seconds in GPS time.
> Pulses occur on even-numbered seconds (i.e., 2 seconds, 4 seconds, etc.).
> ===
> QUESTION:
> What Specific Applications would use this 1PP2S output regularly??
>
> greg
>
> Sent from iPhone 6s
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[time-nuts] chrony vs other NTP

2019-09-26 Thread djl




Any quick opinions re use of chrony vs other NTP implementations?
THANKS
Don
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Re: [time-nuts] FA2 counter

2019-09-26 Thread djl

Got mine today as well, Bert. Haven't gotten a chance to use it yet, 
good to know you had positive results.


Don

On 2019-09-26 11:05, ew via time-nuts wrote:

Did receive FA2 counter today. Everything as promised, like the 10
second mode best.Use a Datum 2000 as source 10 MHz in the back 5 MHz
in the front reliable +- 1 on the last 12th digit.


Bert Kehren
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[time-nuts] Fwd: [New post] 100 Year Old Atomic Clock

2019-09-25 Thread djl

 

fyi, Don 

 Original Message  

SUBJECT:
[New post] 100 Year Old Atomic Clock

DATE:
2019-09-25 11:03

FROM:
Hackaday 

TO:
d...@montana.com

 Gregory L. Charvat posted: "Precision time is ubiquitous today thanks
to GPS and WWVB. Even your Macbook or smartphone displays time which is
synchronized to the NIST-F1 clock, a cesium fountain atomic clock (aka
the 'Atomic Clock') that is part of a global consortium of atomic cloc" 

NEW POST ON HACKADAY

100 YEAR OLD ATOMIC CLOCK [1]

 by Gregory L. Charvat [2] 

Precision time is ubiquitous today thanks to GPS and WWVB. Even your
Macbook or smartphone displays time which is synchronized to the NIST-F1
[3] clock, a cesium fountain atomic clock (aka the 'Atomic Clock') that
is part of a global consortium of atomic clocks known as Coordinated
Universal Time (UTC). Without precise timing there would be train
collisions, markets would tumble, schools would not start on time, and
planes would fall out of the sky. 

But how was precision timing achieved in the 19th century during the era
of steam, brass, and solenoids? One of the first systems of precision
timing kept trains running safely and on time, rang the bells at school,
and kept markets trading by using a special clock designed by the Self
Winding Clock Company. Through measurements of celestial objects by the
US Naval Observatory, and time synchronization pulses broadcast by the
Western Union telegraph network, this system synchronized time across
the United States in an era where the speed of our train system was
out-pacing by the precision of our clocks. 

Those clocks were designed so well that many of them are still around
and functioning. One of these 100-year-old self-winding clocks made its
way onto my workbench. I did what any curious hacker would do, figured
out how the synchronization worked and connected it to a clock source
with atomic precision. Let's take a look! 

Read more of this post [4] 

GREGORY L. CHARVAT [2] | September 25, 2019 at 10:01 am | URL:
https://wp.me/paBn4l-1zSR 

Comment [5]
   See all comments [6]

Unsubscribe [7] to no longer receive posts from Hackaday.
Change your email settings at Manage Subscriptions [8]. 

TROUBLE CLICKING? Copy and paste this URL into your browser: 
https://hackaday.com/2019/09/25/100-year-old-atomic-clock/ 

-- 

Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304 

Links:
--
[1] https://hackaday.com/2019/09/25/100-year-old-atomic-clock/
[2] https://hackaday.com/?author=48350060
[3]
https://www.nist.gov/pml/time-and-frequency-division/primary-standard-nist-f1
[4]
https://hackaday.com/2019/09/25/100-year-old-atomic-clock/#more-376269
[5] https://hackaday.com/2019/09/25/100-year-old-atomic-clock/#respond
[6] https://hackaday.com/2019/09/25/100-year-old-atomic-clock/#comments
[7]
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FtcD0xNTY5NDMwOTQ4LjQ4MDgmcXVldWU9c3luYyZob21lPWh0dHBzJTNBJTJGJTJGaGFja2FkYXkuY29tJnNpdGV1cmw9aHR0cHMlM0ElMkYlMkZoYWNrYWRheS5jb20mY2Q9MC4wMDE5JnBkPTAuMDAxOSZpZGM9MSZ0aW1lb3V0PTMwJmZvcj1qZXRwYWNrJndwY29tX2Jsb2dfaWQ9MTU2NjcwMTc3IiwiX2VuIjoid3Bjb21fZW1haWxfY2xpY2siLCJfdHMiOjE1Njk0MzEwMDQ4ODMsImJyb3dzZXJfdHlwZSI6InBocC1hZ2VudCIsIl9hdWEiOiJ3cGNvbS10cmFja3MtY2xpZW50LXYwLjMiLCJfdWwiOm51bGwsImJsb2dfdHoiOiItNyIsInVzZXJfbGFuZyI6bnVsbH0_z=z
[8]

Re: [time-nuts] 5 Mhz to 10 Mhz and 25 Mhz

2019-09-10 Thread djl

I looked for breakouts/eval boards for these.  Only one I found was 
$250.00 nuts.   maybe an 8=pin SOIC adapter board will do the job? found 
on dear ol' Amazon for cheap.

Don

On 2019-09-09 15:24, Paul Bicknell wrote:

Hi all thank you I have now printed out the dater sheets for

The  ICS570BNB3N502 ICS 512

These are all new to me so my next question are there any PCB's 
available

for any of the above

For best timing  work should I go for Sq wave or sine wave output and 
out of

the 3 is their a preference

Must do some work and reading  so
Thank you to all  Paul B  south coast   UK

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of 
paul

swed
Sent: 09 September 2019 20:10
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] 5 Mhz to 10 Mhz and 25 Mhz

Have to say that chip looks identical to what Burt sent earlier. 
Settings

and all.

On Mon, Sep 9, 2019 at 3:01 PM Bob via time-nuts 

wrote:

You might look at the NB3N502  PLL mult chip. I've used this chip on 
my

rubidium interface board and other projects.  It's cheap, current
production and does a number of multipliers from 2X 2.5X 3X 3.33x 
4X
and 5X  Available from Mouser and others.  I'm using one in a hybrid 
CW
transmitter as a nearly coil-less scheme with a 6CL6 final.  all 5 
bands

from either a 80 meter or 40 meter crystal. Keys really clean too.
Bob, KE6F

-Original Message-
From: paul swed 
To: Discussion of precise time and frequency measurement <
time-nuts@lists.febo.com>
Sent: Mon, Sep 9, 2019 9:01 am
Subject: Re: [time-nuts] 5 Mhz to 10 Mhz and 25 Mhz

Bert was looking at the ICS512 and have to agree the price is cheap. 
How

have you applied them. It seems really simple. Do you follow with
filtering. Looking at 5 > 10 MHz and 5 > 15...
regards
Paul
WB8TSL

On Mon, Sep 9, 2019 at 7:03 AM ew via time-nuts 

wrote:

> PaulThe easiest way is one or two  ICS512 or ICS570B we use the 570
> extensively. Digi Key and ebay have both
> Bert Kehren
> In a message dated 9/8/2019 10:49:33 AM Eastern Standard Time,
> p...@bicknells.f2s.com writes:
>
> Dear all
>
> Can any one point me in the direction of a circuit that can convert
> 5 Mhz signal to give me 2 outputs one at 10 Mhz and another at 25 Mhz
>
>
> Regards Paul B
>
>
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-
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08/14/18

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Re: [time-nuts] FA-2 Precision Frequency Counter BG7TBL 20190622

2019-09-04 Thread djl

Looked around at specs. I don't know that I can believe .01 HZ at 6 
GHz??? Is that approx 10^-11?? even with gpsdo reference and 10 sec 
gate.
But even so, there are possibilities for this device.  I, too, will have 
to downsize my boatanchors someday soon.

Don

On 2019-09-04 14:25, paul swed wrote:

Perry as you have down sized it is a good opportunity to leverage more
modern options.
I can't speak to the quality/accuracy/value of the $100 units. But
Time-nuts can.
The fact is these things are pretty amazing and consume little power 
and
generally have modern USB interfaces and software. Granted they may not 
be

accurate to 100th db... But then rarely have I ever needed that.
I could see that when the time comes to dump my 100s LBs of HP test
equipment I will end up with little boxes. A far lighter bench with 
more

working space and lower power bill.
I have been following the discussions on the FA2. Very unclear on the
conclusion actually.
Regards
Paul
WB8TSL

On Wed, Sep 4, 2019 at 4:05 PM Perry Sandeen via time-nuts <
time-nuts@lists.febo.com> wrote:


Yo Bubba Dudes!,
While looking on ebay at the BG7TBL FA1 analyzer I looked on the 
bottom of
the page where other items are advertised an saw ads for the FA-2 
Precision

Frequency counter which is sold by multiple vendors in the $115 range.
As I have to down-size It appears to be just what I could use albeit 
it

requires a wall-wart PS.:(

It seems to have a very good price/performance ratio.
Does anyone have one or experience with one and could share their
experience?
Regards,
Perrier


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Re: [time-nuts] TAPR TIC Upgrade?

2019-08-14 Thread djl


Would require a real time operating system on the Pi?

On 2019-08-14 16:16, Bob kb8tq wrote:

Hi

Could you? Sure you could.

Should you? How much do you feel like rewriting all the driver
software from scratch?
Do you really want to rewire things to fit to the Raspberry pinout?
That’s either a fairly
simple PCB or a whole bunch of wires.

The main benefits would be the bigger RAM on the 4B and the ethernet
port. If you went
crazy, you could put a display and buttons on it and have an “all in
one” instrument.

Probably easier to leave the Arduino where it is and mate up the 4B
with the serial port
on the Arduino.

Bob

On Aug 14, 2019, at 1:28 PM, Perry Sandeen via time-nuts 
 wrote:


Yo Bubba Dudes!,
I've just purchased a TAPR TIC module.  Now the new Raspberry Pi Model 
B has just been released.
So my question is would there be any worthwhile advantage to replacing 
the TAPR unit with the new Model 4B?

Regards,
Perrier
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Re: [time-nuts] HP 10811 stabilizing time

2019-07-23 Thread djl


Just visited site. 3million hits on
10811 manuals. We're that many made:-)?

On 2019-07-23 05:01, Charles Steinmetz wrote:

Rick wrote:


Basically, no counter that we ever made AFAIK had
any provision for EFC.


The later HP5328 "oscillator helper" boards have EFC pots for fine
tuning the timebase frequency.  This includes the US military versions
that are so prevalent in the US.  I have schematics showing this with
both the 10544 (support board 05328-60027) and 10811 (support board
05328-60038) oscillators (production shifted from the 10544 to the
10811 during the 5328's run).

These work fine, but one can easily build an EFC circuit with much
better drift characteristics (i.e., first-order temperature
compensation).  I published such a circuit some time ago and posted it
to this list at least once.  My circuit also reduces the EFC
adjustment range to make it easier to adjust precisely.

That circuit is on Didier's site (ko4bb.com).  Search for a doc named
"HP 10544 10811 EFC fine adjustment.pdf".

Best regards,

Charles



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[time-nuts] odd frequencies

2019-07-09 Thread djl


I've seen questions here about GPSDO disciplined frequency sources for =

odd frequencies. I recommend the RFZero:   http://www.rfzero.net. For
$60 US or so, this unit will provide same. Is programmed using the
Arduino IDE, several examples provided. All that's needed is a UBLOX
compatible patch or other antenna. Disciplined SI oscillator.  buffer
driver provided, with other goodies.
Don



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Re: [time-nuts] Distribution amplifier for 10MHz and 1 pps

2019-03-17 Thread djl

Gosh. this topic comes up at least once every 6 months. A diligent 
search of the time-nuts database would turn up amazing things. . .



On 2019-03-17 13:24, Hal Murray wrote:
For 1PPs the main goal is jitter and the selection of the ICs is very 
tricky


Could you please say more?  Do you mean logic family selection, or chip
selection within a family?

Most modern digital chips are CMOS with an input threshold of VCC/2.  
I'd
expect power supply noise to be important and families with faster 
switching

times probably make more noise.


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Re: [time-nuts] GN-GGB0710 GNSS Antenna

2019-02-24 Thread djl


Probably tapped for 1/2" pipe thread.
Don

On 2019-02-24 12:40, Ben Hall wrote:

Good evening all,

After almost a month in transit, my GN-GGB0710 GNSS antenna arrived
from the auction site "we all know and love."  ;)

Unit was not tapped to a proper 5/8"-11 TPI thread.  A standard 5/8-11
bolt went in maybe two full threads.  I modified an old tap I had in
the drawer into a 5/8"-11 bottom tap and cleaned it up.  Best I can
tell, the thread cut by the manufacturer was slightly tapered.

I wasn't thrilled with the seal around the edge.  Because it's flat,
some water might wick in, so I ran a quick bead of seal around both
the top and bottom end of the blue rubber seal.

Unit seems to work well.  It's not mounted to the top of my antenna
pole, about 16 feet up from the ground, where it can see a pretty much
unobstructed view of the sky.  All the GPS units on it thru the
splitter are getting excellent signal.

Now to wait until uBlox releases the ZED-F9T dev board.  I did get a
response back from uBlox sales to my work e-mail address (which is a
very large organization) saying it's still in development with a
target release date of May or so...

thanks much and 73,
ben

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Re: [time-nuts] HP Stories: Cesium Standards on Subs and Sperry

2019-02-24 Thread djl


Love milspec stories!   Always reminds me of some of my favorite quotes:

 “Mechanical rules are never a substitute for clarity of thought.” -- 
Brian Kernighan

". . .  rules are a substitute for thought . . ." -- Robert Gunning
 "A foolish consistency is the hobgoblin of little minds . . ." --  R.W. 
Emerson


Don

On 2019-02-24 06:37, Rice, Hugh (IPH Writing Systems) wrote:

While HP wasn't a direct defense contractor, we did sell a lot of test
equipment to defense contractors.The big American submarines had a
Cesium Standard or two as part of their instrumentation systems.I
know little about the application, but heard it was part of the
communication and/or navigation systems.Maybe some of you have
experience with this, and can add to the story.

None the less, Sperry corporation was a sub-contractor into the
greater DOD eco-system, and integrated the 5061A into some larger
system they sold to the submarine builders.Sperry was a "real"
defense contractor, and had to live by all the DOD rules.There
were a number of defense contractors in Silicon Valley, with Lockheed
Missiles and Space Company being perhaps the largest employer in the
area.   Both my father, and my wife's father were engineers at LSMC
for their careers.   We used to joke at my High School that
"everyone's dad worked for Lockheed."Thus, DOD companies were not
a foreign concept to me.   But they way the DOD procurement process
worked was very unlike how HP worked and interfaced with our
commercial customers.

Sperry wanted to turn HP into defense supplier when they purchased
5061A's from us.   First, they had their special "Sperry Blue" paint
job.   Our sheet metal and paint shops had to custom build the
cosmetic parts for Sperry in a lovely baby blue color.Next, they
wanted to make sure what was purchased was exactly what was specified.
 EXACTLY.   The technique to enforce this was to document and inspect
everything.A special Sperry material list was created, with every
resistor, screw and wire listed.   HP part numbers, approved
suppliers, and supplier part numbers, for everything.   It turns out
there are a lot of components in a 5061A. Sperry would then insist
that HP segregate all the components that were going into their sacred
5061As, and have our incoming quality department inspect every single
tiny part, to ensure it was the correct component, coming from proper
suppliers.   The attention to detail was both impressive and
maddening.This was way outside our normal
 manufacturing processes, and a huge hassle.

The representatives from Sperry were from a different planet than HP
people.This part of Sperry had it's headquarters in the NYC area,
and the lead representative was like a movie character from a God
Father movie.   Short, plump, arrogant, Italian, in charge.  He was
THE MAN, and expected to be treated as such.  He was cordial on the
surface, but was unmovable when trying to negotiate what we though
would be a sensible compromise of some kind. To him, change, any
change, was bad.Because if anything ever happened, for the rest of
human history, that could be traced back to a change he allowed, he
would be held accountable.He wanted to be held accountable for
buying 8  Cesium Standards, not for adding risk to that purchase.
He had a young assistant to grind through all the details.   This guy
was about 30, and knew his role in the game.   There were procurement
rules his company must follow, and his job was to make sure every
detail got done.  EVERY DETAIL.He br
 ought exactly zero judgment or critical thinking to the process.

Mr. Mafia man told a story about why not changing things was so
important.  As I recall, Sperry made some kind of targeting system for
artillery, probably dating back to WWII, and a vendor had upgraded the
insulation on some wiring from a fabric weave to more modern extruded
plastic insulation.For some reason this led to a failure.  (Likely
heat related).   This was used as indisputable proof that even the
most innocent looking changes can cause a problem, problems are the
enemy, and change was it's root cause.

And then HP invented the 5061B, and changed a bunch of stuff from the
5061A.   Sperry had a contract that required another batch of HP
Cesium Standards, and  wanted nothing to do with the 5061B.   They had
made several previous purchases of 5061As, and their overall system
had not changed, and they didn't want the Cesium Standard to Change
either.Since I was the 5061B guy, and young and expendable and
ignorant (never had worked with Sperry before), I was assigned the
task of getting Sperry happy with the 5061B.I remember Jeanie
Young, an energetic women from our marketing department being the lead
contact with Sperry on business stuff (fuss with contracts, and be
responsible for the wine-and-dine aspects), as I did the
"engineering".

I think our basic position is that not only we don't make the 5061A
any more, we COULD

Re: [time-nuts] PPS clock module

2019-01-28 Thread djl


Aha! cosidering opportunity cost, not overkill at all!

On 2019-01-28 07:38, John Ackermann N8UR wrote:

On 1/27/19 5:18 PM, Tim Shoppa wrote:

Today - get an Arduino Nano clone ($3) and a 6-digit-7-segment module 
or

dot matrix module ($10).


Hi Tim --

Yup, that's probably the answer in the end, even though it's way 
overkill.


73,
John

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Re: [time-nuts] PPS clock module

2019-01-28 Thread djl


John: a little fiddling, but:
epay #172166404085
Don

On 2019-01-27 15:54, Bill Beam wrote:

I went thru this several years ago and ended up home brew with the
following circuit:

For adjustment of time indication I added switches to run hours and
minutes at 1 pps
rate and a switch to stop seconds. Some always on leds for colons to
make it look
like a clock.
There are many other circuits out there but no complete commercial 
units.


On Sun, 27 Jan 2019 15:48:40 -0500, John Ackermann N8UR wrote:

I'm putting together a portable Rb standard and thought it would be 
nice

to include a clock on the panel.  I probably haven't hit the magic
search words, but I haven't found what I'm looking: a module (no
enclosure) that is driven by an external PPS and shows at least 
HH:MM:SS

in 24 hour format on a small LED or LCD display.


I can whip something together with an Arduino, but rather than 
reinvent
the wheel I thought I'd ask if anyone knows of something that's ready 
to go.



Thanks,
John



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Bill Beam
NL7F




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[time-nuts] rf generator/attenuator

2018-12-15 Thread djl


See:
sv1...@40gmail.com
modules to do what you wanted. With a nice oled and arduino, ADF4351=20
35-4400 MHz PLL external or internal 10 MHz reference and a controllable
attenuator. Greek modules, not Chinese. Total cost seems to be about $80
or so.
  I also found modules like these on EBAY for around $25 each from the
old country. hurry before the tariffs start! I think serviceable signal
source, GPSDO locked, can be built from modules for under $100
Considering my first Polarad microwave generator at about 60 pounds and
able to heat the shack, it's a bargain. Time spent looking, about 15 
minutes.

Don

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Re: [time-nuts] Modern signal generators

2018-12-11 Thread djl

Rick: I've spent some time with the dds blocks. We found them to 
generate lots of low level spurs, making lots of "birdies" when used as 
local oscillators in receivers.

We had better results using:
https://www.silabs.com/products/timing/oscillators.

These may be used with GPSDO clocks for accuracy, and generate less 
noise. Cost is about the same; there are two or three sources for 
breakout units. The clock sources do have to be 25/27 MHz, those from 
Leo Bodnar, or use an OCXO.  Digital attenuators are also available; all 
this can be run from an Arduino with oled or other readouts, libraries 
abound. And for quick and fancy GUI, on a pc, use MakerPlot.

Just $.02
Don

On 2018-12-11 09:46, Richard (Rick) Karlquist wrote:

Another gold mine.  I used to work for Agilent/Keysight so I
am very familiar with their signal generators.  It
will be interesting to see the R viewpoint.  The DDS
stuff is very valuable.  I have been considering using
a DDS eval board with a low noise 1 GHZ reference to
make a poor man's signal generator for my home lab.
Your paper will be required reading.  I suspect a lot
of time nuts are in a similar situation as me.

Thanks.

Rick

On 12/11/2018 7:23 AM, Ulrich Rohde via time-nuts wrote:
  
https://badw.de/fileadmin/members/R/3685/6_4_18_UNI_BW_June18-safe.pdf

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Re: [time-nuts] WWV/H Doppler Shift

2018-11-27 Thread djl

Tom: Thanks!   Rob: your toolchain (to borrow a phrase) produces great 
results.  If I read the graphics right, you might be able to obtain some 
outstanding results from the HAARP Research Campaign 29 Nov - 03 Dec 
2018.  U of Alaska Fairbanks Geophysical research Institute. A thought 
from another QS1R user. (btw, I'm told the QS1R is at the heart of the 
Icom IC-7300 SDR transceiver.)

Good stuff
Don

On 2018-11-27 20:39, Tom Van Baak wrote:

FYI: The wonderful plots that Rob included in his posting an hour ago
did not make it to the list. This is because they were inline or
embedded within html rather than plain file attachments.

Anyway, I recovered his images and they are attached to this posting:

plot_5.0_dBm_2018-11-25.jpg
plot_5.0_Hz_2018-11-25.jpg

/tvb
Moderator, www.leapsecond.com/time-nuts.htm

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Re: [time-nuts] NIST

2018-08-30 Thread djl


Is there a translation of this anywhere?
Don



Sweden were much more serious about it:

http://www.antus.org/RT02.html

Tl;drs:

They erected 9 200m tall Loran-C class antennas each driven by
a Loran-C transmitter with an advanced degree which could jam
Loran-C or Chayka.

They even mounted decoy parabolas on the towers them to hide their
true purpose.

The fact that all the transmitters were on the east coast does drop
a hint that swedens much touted neutrality had a bit of a slant.


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Re: [time-nuts] Loss of NIST transmitters at Colorado and Hawaii

2018-08-12 Thread djl

Well, maybe NIST wants to cut, and maybe not.  What happens is, in zero 
based budgeting, the chain of command will pass down the line requests 
for budgets for the coming year with cuts of varying depth. After a 
couple of cuts everywhere, travel for example, an agency will seek 
programs that can be cut and managers will have to make several 
suggested budgets. I have done this, and have had to cut as much as 30 
percent out of mine. Since budget cuts are very hard to use as reason 
for layoffs, operating funds have to take up the slack. So this may not 
come to anything.
The land, if not leased, is probably managed by the GSA, an arm of 
Congress rather than the executive branch. I'll bet most of you can 
figure out why this is so.  NIST will not see a dime from any sale.

Anyway, that's an end to my contributions to this thread.
Selah.
Don

On 2018-08-12 19:46, paul swed wrote:
What bits I have read do seem to indicate its NIST that wants to cut 
the
service. Since technology has moved beyond the services value which is 
kind

of true. Just think what they can get for the land the sites on.
Microsemi's comments were interesting in that in some manner there 
might be
a NTP based solution that could be far more accurate then what we 
typically
see today for NTP. But it also seemed to hint it would be a fee 
service. I

think thats very very early.

Regards
Paul
WB8TSL


On Sun, Aug 12, 2018 at 8:37 PM, Wes  wrote:

Comment in the link about visiting WWV reminds me of my experience.  
Many
years ago my late wife and I were roving around Colorado and I 
telephoned
WWV and asked if I could get a tour. I mentioned that I was a ham, an 
EE,
blah blah. This had worked before at other installations (not NAA 
however)

including the Apollo tracking station at Guaymas Mexico a day after a
splashdown.

The fellow I talked to was somewhat taken aback and said that they 
didn't
give tours.  I expressed some dismay and was about to hang up when he 
said,
"Actually, we have some contractors doing some work here and the gate 
is

unlocked.  If you were to come in you could look at the antennas, but
please stay in your car."  So we did.

Wes



On 8/12/2018 4:05 PM, Bill Hawkins wrote:



Group,

This subject needs some additional detail.  I found an article with
comments at

https://swling.com/blog/2018/08/nist-fy2019-budget-includes-
request-to-shutdown-wwv-and-wwvh/




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Re: [time-nuts] Bicentennial GOES satellite clock

2018-08-12 Thread djl

all you need for a once a day noon fix is a level surface, a stick, and 
some pebbles.

Don

On 2018-08-12 08:29, Scott McGrath wrote:

And with dependence on GPS we have created a serious vulnerability as
too many critical pieces of infrastructure are dependent on a SINGLE
precision timing and positioning system.

I can use a sextant and have a copy of Bowditch.But they only work
on clear days and nights.

if GPS goes down for any reason.   Whats the backup solution?


On Aug 10, 2018, at 2:25 PM, Lester Veenstra  
wrote:


Used to work with Wayne on two time transfer via satellite
Great guy


Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
les...@veenstras.com

Physical and US Postal Addresses
5 Shrine Club Drive (Physical)
HC84 452 Stable Ln (RFD USPS Mail)
Keyser WV 26726
GPS: 39.336826 N  78.982287 W (Google)
GPS: 39.33682 N  78.9823741 W (GPSDO)


Telephones:
Home: +1-304-289-6057
US cell+1-304-790-9192
Jamaica cell:   +1-876-456-8898


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of 
Tom

Van Baak
Sent: Friday, August 10, 2018 10:19 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Bicentennial GOES satellite clock

Tim,

Thanks for posting that photo. That space age 1976 GOES clock caught 
our

eyes when the paper came out in 2005 (see also pages 11, 12, 13):

https://tf.nist.gov/general/pdf/2013.pdf

There was quite a bit of traffic on time-nuts around 2005 when the GOES
satellite time service was turned off (and back on, and off, and on, 
and

finally off for good). That left many of us with piles of 468 MHz GOES
receivers, antennae, clocks and led to efforts to re-create the RF 
signals
in-home so that GOES clocks would still work. There was even a 
commercial

G2G (GPS to GOES) translator.

Anyway, I asked around about that one-off bicentennial clock in the 
photo

and neither the authors, NIST, or Smithsonian knows where it ended up.
There's tons of information on the GOES satellite system and GOES 
clocks in

the NIST T archives:

https://tf.nist.gov/general/publications.htm

Best to search title for GOES, or search author for Hanson. It's a
fascinating glimpse into the recent past. Yes, it's sad that GOES (and
Omega, and Loran-C) aren't operational anymore, but GPS does such a 
better
job. Plus we now have cable, WiFi, cell phones, the internet, Iridium, 
etc.


If you wanted to build your own Bicentennial GOES Clock, the design was
published, including source code -- for its i4004 (!!) CPU. If you have 
even

one minute to spare, see attached image and click on these two PDF's:

"Satellite Controlled Digital Clock System (patent)"
https://tf.nist.gov/general/pdf/1791.pdf

"A Satellite-Controlled Digital Clock (NBS TN-681)"
https://tf.nist.gov/general/pdf/452.pdf

/tvb


- Original Message -
From: "Tim Shoppa" 
To: "Discussion of precise time and frequency measurement"

Sent: Wednesday, August 08, 2018 7:29 PM
Subject: [time-nuts] Bicentennial GOES satellite clock



See the groovy picture at
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4847573/figure/f9-j110-2lom/

If anyone knows the whereabouts or history of the bicentennial GOES 
time

clock display, please let me know!

Tim N3QE




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Re: [time-nuts] NIST

2018-08-12 Thread djl

Just a word:   When budget cuts are announced, the agencies put the most 
valued "stuff" to be cut first, such as the Washington monument, etc. 
This is a recognized ploy. When the dust settles, all may be well. . .

Don

On 2018-08-12 12:20, paul swed wrote:

Like all of you I have a few wwvb clocks that work pretty well here in
Boston.
Certainly have written enough wwvb stuff and created various wwvb 
projects

that I will have to get back into it again.
I did look at the cron-verter. Have to say it has a lot of nice 
features.

Unfortunately it hasn't been available for a year or so. (Getting lazy)
The good news is the AM modulation of wwb is very easy to create.
Regards
Paul
WB8TSL

On Sat, Aug 11, 2018 at 10:48 PM, Dana Whitlow 
wrote:

I fear the worst.  The line in the website simply stated something 
like

"shutting down
the transmitters in Colorado and Hawaii", which would seem to include 
the

whole
enchilada.

For the wall clocks, GPS should work well if people are willing to go 
to

battery-
backed AC power.  But not so good for wristwatches, where the 
expectation

is to
run at uW power levels.  I for one would be very irritated at having 
to

take my watch
off my wrist and put it on a charging stand every night.  So if this
shutdown comes
to pass, I'll be looking for an inexpensive GPS-to-WWVB converter, or 
at

least
plans for building one.

Dana

On Sat, Aug 11, 2018 at 8:12 PM, Bob Albert via time-nuts <
time-nuts@lists.febo.com> wrote:

>  With any luck, the current administration will successfully push the USA
> down technically.  Denying global warming, shutting off time signals, and
> so on, is great stuff.
> On Saturday, August 11, 2018, 6:10:12 PM PDT, Bob kb8tq <
kb...@n1k.org>
> wrote:
>
>  Hi
>
> One would *guess* that stopping WWVB (and killing mom and pop’s “atomic
> clocks”) would not be a reasonable thing to do.
> It gets a lot of voters mad. I doubt that very many voters (percentage
> wise) would notice WWV and WWVH going away ….
>
> Bob
>
> > On Aug 11, 2018, at 9:00 PM, jimlux  wrote:
> >
> > On 8/10/18 12:45 PM, Robert LaJeunesse wrote:
> >> I'd say it does get more detailed, with the $49M in cuts described
> generally in groups here:
> >> https://www.nist.gov/director/fy-2019-presidential-budget-
> request-summary/fundamental-measurement-quantum-science-and
> >> One item: "-$6.3 million supporting fundamental measurement
> dissemination, including the shutdown of NIST radio stations in Colorado
> and Hawaii"
> >
> > I wonder if that's WWVB, or WWV & WWVH
> >
> > ___
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Re: [time-nuts] WTS: Efratom PTB-100 Precision Timebase

2018-07-08 Thread djl

Greg et.al. IEEE stuff is just too expensive for single purchase. I have 
found, to my sorrow over 40 odd years, that they also do not contain 
 information, that is, info of actual use, because some other 
company or person might actually benefit. In other words, the papers are 
markers in the sand.
Now, this is my own opinion, a bit harsh, admittedly. Of course the 
citations do need to be mentioned.
BTW, any published material generated with government funds that is not 
classified belongs to the people, and is not copyrighted. I wonder if 
that includes IEEE papers? that is, if anyone buys one, it can be copied 
or distributed without restriction?

Not being in the lawyer class, I can't say for sure...
Thanks
Don

On 2018-07-08 10:39, Gregory Beat via time-nuts wrote:

Magnus -
When I scan/read the 1984 IEEE document, “Lifetime and Reliability of
Rubidium Discharge Lamps for Use in Atomic Frequency Standards”
by Aerospace Corp., Efraton-Ball, and EG
https://ieeexplore.ieee.org/document/1537723/
The failure of the rubidium lamps used on early NAVSTAR satellites,
was the reason for in-depth studies of the Rb lamp, its lifetime and
failure mechanism.

greg


Hi -
I later tried that method on my R XSRM rubidium, with good progress. 
I

have reported on that on the list way back. It took two attempts, one
just to realize that I needed to keep the pinch at the top, because 
that

is where the hot atoms go.

Essentially, the thin film of rubidium will consume too much of the
radiation to emit any useful amount of pumping light. Heating it has 
the
rubidium go into gas and then collect somewhere cold, so it's just 
about
making sure that somewhere cold isn't the glass where it is to emit 
light.


My XSRM have however other issues that I need to attend to.

Cheers,
Magnus


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Re: [time-nuts] GPS Antenna Grounding/Lightning protection.

2018-06-19 Thread djl


First, I recommend the following:
http://www.arrl.org/shop/Grounding-and-Bonding-for-the-Radio-Amateur/
well worth the price.
second, bleeding off does not prevent discharge. Many such systems are 
garbage or worse. "bleeding off" is corona discharge from sharp points 
submitted to a large electric field, such as under or near a 
thunderstorm. It's gonna happen.
I think what's meant here by a halo system is a conductor dug in to a 
shallow trench? If so, Scott is correct.
next, most of the time, damage is done by induced currents rather than 
direct hit by the stroke terminus. These can be eased by proper power 
treatment and good single point grounds. I personally do not trust MOV 
ground protectors. They are only good for a certain, unknown, number of 
hits, and are useless after that. There is no way to tell if the limit 
has been reached.  Surge protection on AC power needs doing only at the 
main breaker box from each side of the 220 to ground.
and, if you are on a tower and hear the sizzling noise of corona, get 
down pronto.

Hope this helps.
Don

On 2018-06-19 12:55, Bob kb8tq wrote:

Hi

If indeed a proper ground system *could* be depended on to “bleed off”
and prevent discharge things
would be *much* simpler. Indeed I’ve been on towers and decided to
exit that location as the bleed
process became audible. It very much does happen. It simply is not a
100% sort of thing.

Bob

On Jun 19, 2018, at 12:01 PM, Scott McGrath  
wrote:


Probably the easiest and most economical grounding system is the halo 
ground with antenna grounds bonded to the halo and the house ground 
bonded to the halo as well.


The halo conductor sizing is governed by local codes,   But really 
what you are doing ensuring that the entire structure and earth around 
it is at the same potential so a nearby strike does not cause ground 
currents to flow.


A direct strike is probably going to fry anything it hits because of 
the gigajoules of energy concentrated within the discharge


But a proper ground system also ‘bleeds off’ the potential difference 
thereby preventing discharge


Content by Scott
Typos by Siri

On Jun 19, 2018, at 11:19 AM, Bob kb8tq  wrote:

Hi

18” down in a swamp likely is plenty for conductivity. 18” down in a 
sandy desert (or on an ice sheet) may be way
short in terms of conductivity :) The real answer to any of this is 
“that depends”. (Yes, the ice sheet grounding
problem is from a real case that shows up in some class notes from way 
back ….).


Some locations get multiple  hits on a weekly basis in the summer. 
Other locations get a close strike once every
few decades. What makes economic sense for one probably does not make 
sense for the other…. A “full up”
protection setup can easily run into hundreds of thousands of dollars. 
I’d much rather spend that kind of money

on a Maser … or two …. or three :) …. this is TimeNuts after all ….

Bob



On Jun 19, 2018, at 10:56 AM, Scott McGrath  
wrote:


The 18” inch requirement is partially for damage resistance and 
partially to ensure adequate soil moisture for conductivity.


Content by Scott
Typos by Siri

On Jun 19, 2018, at 10:50 AM, jimlux  wrote:

On 6/18/18 6:39 PM, Glenn Little WB4UIV wrote:

To do the grounding correctly, all connections exterior to the 
building are to be welded.

The cable to ground rod welds are to be 18 inches below grade.
The exterior cable is to be number 2 copper or larger.
To bond numerous ground systems together, a number 2 copper cable is 
to be buried at 18 inches and welded to each ground system.
If using eight foot ground rods, a ground rod is to be driven every 
16 feet along the connecting cable and the cable welded to the rod.



It helps to know *why* some requirements exist - I suspect the 18" 
burial requirement is to avoid accidentally digging it up or damaging 
it. I can't think of an electrical reason for it.



A lot of work, but, cheaper, in the long run, than continuing to 
repair/replace equipment.


It depends

Unless you're doing geodetic or precision timing work with a 2 or 3 
band GPS, replacement GPS antennas are cheap.
I'd worry about the receiver and related equipment, but the antenna 
itself might be sacrificial.


As always, there's a risk/budget tradeoff




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