Re: [time-nuts] WWVB New Modulation scheme...

[Chuck Forsberg WA7KGX N2469R]

I have my 3586b slaved to my Thunderbolt along with a
Flex-1500 radio, Racal-Dana counter, Advantest Spectrum
analyzer and Gigatronics signal generator.

You might be interested to know KEX 1190 in Portland
is about 30 kHz low.  At least they aren't spewing
IBOC lately.

--
Chuck Forsberg WA7KGX N2469R c...@omen.com   www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
  Omen Technology Inc  "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430


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[time-nuts] WWVB New Modulation scheme...

[Burt I. Weiner]

If I sent these thoughts before, pardon me as I'm suffering from CRS Syndrom.

Part of the normal work I provide is off-air measurements of 
broadcast stations.  Would you believe, they pay me to do 
this!  Anyway, I measure AM carriers, FM carriers, and TV, both 
analog and digital pilots, as well as other stuff.  For FM stations I 
also measure any subcarrier including the RDBS signal at 57 kHz.


My method for measuring is described 
Here:  http://www.k5cm.com/k6OQK%20FMT%20NEW.htm  The methodology 
described here is used for primarily for AM Broadcast signals, but 
can be used for FM subcarriers also.


Some time ago I tried measuring the RDS signal in the broadcast FM 
baseband  With my trusty 3586B looking at the baseband of my FM 
receiver I tried tuning the 3586B SLM to 57 kHz and looked at the 
resultant 15625 Hz I.F. out of the 3586B as described in the above 
article.  It was a useless mess.  Due to the nature of the 57 kHz RDS 
modulation, which is not FM, I just couldn't get a meaningful 
measurement.  Rats!


One day while poking around and looking at the 57 kHz RDS signal, 
rather than using 20 Hz bandwidth, which is really about -3 dB at 6 
Hz, I used the 3.1 kHz bandwidth position.  Lo and behold, I now had 
a very well defined display that looked very similar to the eye 
pattern used for examining digital transmissions.  I was allowing 
both sidebands into the 3586B and was now able to measure down to 
milliHertz resolution with no problem.  All I had to do was adjust my 
3336B (read the above linked article) to get the pattern to stand 
still as either a circle or and X on the scope.


I still need to dig into this a bit farther because the RDS signal 
really does not have a carrier as such.  It has the two sidebands 
depending on the phase shift determined by the data.  However, I do 
know that RDS generators that are GPS referenced give me a stationary 
pattern when I'm tuned to 57000.000 Hz.  The RDBS signal is supposed 
to be locked to the third harmonic of the 19 kHz pilot, which has a 
+/- 2 Hz tolerance.  The truth is that they're not always locked, and 
I know of several stations that do not feed a Pilot reference to the 
RDBS generator.  FM broadcast RDS injection levels are typically 
about 2-5 percent of +/- 75 kHz deviation, but it is not a FM signal 
when you look in the FM baseband.  Anyway, just a thought that maybe 
if you look at the WWVB signal with a wider bandwidth it might be 
interesting.  I really need to take the WWVB loop off of my 
Symetricom 8170 and hook it to my 3586B SLM and see for myself.


For what it's worth,

Burt, K6OQK


Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
b...@att.net
www.biwa.cc
K6OQK 



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Re: [time-nuts] Timing performance of servers

[Jim Lux]

On 10/25/12 11:02 AM, li...@lazygranch.com wrote:

The GPS seeing the horizon isn't required. Those satellites are filtered out by 
software. The timing GPSs are designed to be less sensitive to the horizon.




when tracking a satellite above the cutoff, you still want the antenna 
to not respond down to the horizon, because that might be where the 
multipath is coming from.



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Re: [time-nuts] Disciplining a TCXO

[Bob Camp]

Hi

If you want to dig into some papers, the RBXO (rubidium and OCXO) is 
essentially the same thing.

Bottom line:

As long as aging + repeated temperature is the dominant effect, it works fine. 
As soon as you get a temperature transient - not so much. Worst case is when 
the temperature delta happens right after the GPS shuts down.

Bob

On Oct 25, 2012, at 8:46 PM, Tom Harris  wrote:

> Greetings,
> 
> I have been asked the viability of using a vanilla TCXO, with an
> accuracy of +/- 0.5ppm (+/- 15 secs per year) that is disciplined
> occasionally (perhaps only once a month) with a GPS module. The
> application is for an analogue clock, which powers up a GPS module
> every so often to learn the drift characteristics of the TCXO, which
> it then compensates to generate indicated time. The TCXO's that I have
> played with have a very predictable aging characteristic over time, at
> least in a normal home/office environment.
> 
> 
> 
> -- 
> 
> Tom Harris 
> 
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[time-nuts] Disciplining a TCXO

[Tom Harris]

Greetings,

I have been asked the viability of using a vanilla TCXO, with an
accuracy of +/- 0.5ppm (+/- 15 secs per year) that is disciplined
occasionally (perhaps only once a month) with a GPS module. The
application is for an analogue clock, which powers up a GPS module
every so often to learn the drift characteristics of the TCXO, which
it then compensates to generate indicated time. The TCXO's that I have
played with have a very predictable aging characteristic over time, at
least in a normal home/office environment.



-- 

Tom Harris 

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Re: [time-nuts] SR620 VCTCXO replacement

[Tom Miller]

Oh my, that looks like a good deal. I'll have to order a few.

Regards,
Tom


- Original Message - 
From: 

To: 
Sent: Thursday, October 25, 2012 3:59 PM
Subject: [time-nuts] SR620 VCTCXO replacement


Hi,

Check this one out! I think it might work as long as the +5 volts can
source the oven current required.

Your part was 20ma.

This one requires About 250 ma during warmup and between 80 and 130ma
afterwards.



http://www.ebay.com/itm/310380778466?ssPageName=STRK:MEWNX:IT&_trksid=p39
84.m1439.l2649

Corby



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Re: [time-nuts] WWVB New Modulation five cent demodulator / carrier regenerator ?

[paul swed]

Tom I shifted to 60 Khz using a synth Gen. The 60 Khz for the encoder comes
from another sig gen and they are all locked to an Rb.
Yes thats a sucker price, at least for me.
Regards
Paul.

On Wed, Oct 24, 2012 at 11:05 PM, Tom Miller  wrote:

> Hello Paul,
>
> I guess you tested it at 57 kHz? Were you able to get it to work with your
> simulator at the normal frequency?
>
> Does anyone have details on the test mode?
>
>
> I just picked up $3 worth.
>
>
> Regards,
> Tom
>
>
>
> - Original Message - From: "paul swed" 
> To: "Discussion of precise time and frequency measurement" <
> time-nuts@febo.com>
> Sent: Sunday, October 21, 2012 11:08 PM
>
> Subject: Re: [time-nuts] WWVB New Modulation five cent demodulator /
> carrier regenerator ?
>
>
> Jameco had them on sale for 20 cents each so I purchased some.
> Moved the clock up frequency for 60 Khz and injected the 60Khz BPSK. (I
> built a simulator) It did not track and in general produced noise. I
> understand you can use 2 frequencies to drive it and I tried both from
> synth gens.
> I was looking at the RDS decoders and the data seemed to be differential.
> Set it aside at that point. I am curious as to why it did not work. Like
> everyone here would be great if it worked
> Regards
> Paul
> WB8TSL
>
> On Sun, Oct 21, 2012 at 10:55 PM, Dale J. Robertson 
> wrote:
>
>  Paul,
>> I'm trying to understand your reference to 'differential BPSK'  all the
>> RDS references I've looked at indicate a 180 degree phase shift just like
>> WWVB. I'm thinking that differential and antipodal are just different
>> words
>> for the same thing
>> Regards,
>> Dale
>>
>> Sent from my iPhone
>>
>> On Oct 21, 2012, at 10:03 PM, paul swed  wrote:
>>
>> > Because it use differential BPSK. I have a number of them and was trying
>> > it. There is a test pin that might make it useful.
>> > Regards
>> > Paul
>> > WB8TSL
>> >
>> > On Sun, Oct 21, 2012 at 9:14 PM, Dale J. Robertson 
>> wrote:
>> >
>> >> While looking for other stuff I came across the data sheet for the NXP
>> >> Semi SAA6579.
>> >> The chip is a purpose built demodulator for RDS (which utilises a 57
>> >> KHz
>> >> ABPSK subcarrier on FM broadcast that is) used for traffic, song info
>> etc.
>> >> This chip has an anti-aliasing front end low pass filter and an 8th
>> order
>> >> bandpass filter followed by a costas loop and provides a phase
>> synchronous
>> >> regenerated carrier. What's interesting is that the switched cap
>> bandpass
>> >> filter and the synchronous detector are both driven by clocks derived
>> from
>> >> a local crystal oscillator which is spec'd at 4.332 or 8.664 MHz (76 or
>> 152
>> >> X carrier chosen by a mode select pin) I'm thinking it should be
>> possible
>> >> to use a 4.56 or 9.12 MHz crystal or external clock to use this chip
>> as-is
>> >> on 60 KHz.
>> >> Have a look at the data sheet and tell me why I'm full of it.
>> >> Jameco is closing out these chips in DIP-16 at a nickel apiece,
>> >> $3.00/hundred.
>> >>
>> >> Dale NV8U
>> >>
>> >>
>> >> ___
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[time-nuts] SR620 VCTCXO replacement

[cdelect]

Hi,

Check this one out! I think it might work as long as the +5 volts can
source the oven current required.

Your part was 20ma.

This one requires About 250 ma during warmup and between 80 and 130ma
afterwards.



http://www.ebay.com/itm/310380778466?ssPageName=STRK:MEWNX:IT&_trksid=p39
84.m1439.l2649

Corby

Woman is 53 But Looks 25
Mom reveals 1 simple wrinkle trick that has angered doctors...
http://thirdpartyoffers.juno.com/TGL3141/50899a8421dd41a8434a7st01duc

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Re: [time-nuts] Timing performance of servers

[lists]

The 20 degree cutoff is what I recall the starloc uses as a default. Now I 
don't know how important it is to filter those out by the response pattern of 
the antenna versus by software.  

-Original Message-
From: "Rob Kimberley" 
Sender: time-nuts-boun...@febo.com
Date: Thu, 25 Oct 2012 20:24:58 
To: 'Discussion of precise time and frequency measurement'
Reply-To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Timing performance of servers

We used to filter out anything 10 - 20 degs above the horizon when setting
up timing receivers. Typically there's a lot of noise down low (multipath
and tropo effects). As long as you've got plenty of SVs you don't need to go
way down to the horizon.

Rob Kimberley

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: 25 October 2012 20:09
To: li...@lazygranch.com; Discussion of precise time and frequency
measurement
Subject: Re: [time-nuts] Timing performance of servers

On Thu, Oct 25, 2012 at 11:02 AM,   wrote:
> The GPS seeing the horizon isn't required. Those satellites are filtered
out by software.

OK, technically it needs to see down to within 10 degrees of the
horizon.   But when you are choosing a location for the mast to the
horizon or withing 10 degrees of it looks pretty much the same.   I
don't want a huge tree of building due south of the antenna.  But for
timing all you really need is to see "most" of the sky.   It depends
on if you want it to work or work as well as it can.


Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Timing performance of servers

[Rob Kimberley]

We used to filter out anything 10 - 20 degs above the horizon when setting
up timing receivers. Typically there's a lot of noise down low (multipath
and tropo effects). As long as you've got plenty of SVs you don't need to go
way down to the horizon.

Rob Kimberley

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: 25 October 2012 20:09
To: li...@lazygranch.com; Discussion of precise time and frequency
measurement
Subject: Re: [time-nuts] Timing performance of servers

On Thu, Oct 25, 2012 at 11:02 AM,   wrote:
> The GPS seeing the horizon isn't required. Those satellites are filtered
out by software.

OK, technically it needs to see down to within 10 degrees of the
horizon.   But when you are choosing a location for the mast to the
horizon or withing 10 degrees of it looks pretty much the same.   I
don't want a huge tree of building due south of the antenna.  But for
timing all you really need is to see "most" of the sky.   It depends
on if you want it to work or work as well as it can.


Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Timing performance of servers

[Chris Albertson]

On Thu, Oct 25, 2012 at 11:02 AM,   wrote:
> The GPS seeing the horizon isn't required. Those satellites are filtered out 
> by software.

OK, technically it needs to see down to within 10 degrees of the
horizon.   But when you are choosing a location for the mast to the
horizon or withing 10 degrees of it looks pretty much the same.   I
don't want a huge tree of building due south of the antenna.  But for
timing all you really need is to see "most" of the sky.   It depends
on if you want it to work or work as well as it can.


Chris Albertson
Redondo Beach, California

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Re: [time-nuts] time-nuts Digest, Vol 99, Issue 111

[Edgardo Molina]

Dear Jacques,

Very interesting your studio work and experiences. I bought a year ago a couple 
of second hand GPS receivers and Leitch clocks belonging to TV studios and 
radio stations so I can imagine a little bit of what you are talking about. 

I am interested in sharing the experiences with Beagle Bone. I got one 
recently. I would like to use Linux instead of FreeBSD. If you wish we could 
correspond over the email to do some tests and try to get two versions of the 
micro NTP box.
 
What do you think about it?

Regards,



Edgardo Molina
Dirección IPTEL

www.iptel.net.mx

T : 55 55 55202444
M : 04455 20501854

Piensa en Bits SA de CV



Información anexa:




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On Oct 25, 2012, at 4:17 AM, Jacques Tiete  wrote:

> Hello Magnus,
> 
> I know what you're talking about, I'm working for a company specialized in 
> broadcasting (from studio's to stations to satellites...) and in this world 
> correct 
> timing is paramount, we live by the 1/25 second rythm and even less if you 
> have to sync on a line in the image ;-).
> Some time ago we were instaling a complete TV station and had huge problems
> with image stability and also especially the correct starting time of a clip 
> or transmission.
> Nobody wants to start his newsreel at eg. 20:00:05;23... it must be 
> 20:00:00;00
> We were looking into this and noticed that the customers servers (Win!) where 
> synced by SNTP, this is plain c..p!
> Have a look @ http://technet.microsoft.com/en-us/library/cc773013(WS.10).aspx
> Especially where it says:
> "Important 
>  The W32Time service is not a full-featured NTP solution that meets 
> time-sensitive 
> application needs and is NOT SUPPORTED by Microsoft as such. For more 
> information, 
> see Microsoft Knowledge Base article 939322, Support boundary to configure 
> the 
> Windows Time service for high-accuracy environments."
> 
> Also have a look @ http://support.microsoft.com/kb/939322
> It says:
> "We do not guarantee and we do not support the accuracy of the W32Time 
> service 
> between nodes on a network. The W32Time service is not a full-featured NTP 
> solution
>  that meets time-sensitive application needs. The W32Time service is 
> primarily 
> designed to do the following:
> Make the Kerberos version 5 authentication protocol work.
> Provide loose sync time for client computers.
> The W32Time service cannot reliably maintain sync time to the range of 1 to 2 
> seconds. 
> Such tolerances are outside the design specification of the W32Time service."
> 
> So it is...   1 to 2 seconds
> 
> Our video playout servers are decent super stable units that use heaps of 
> Xilinx FPGA's
> for coding/decoding videostreams supervised by a mil-spec VXworks OS, it uses 
> the 
> so-called LTC for synchronising the playout, implemented mostly in hardware so
> I did not suspect our machines. I did install a new TCG (TimeCode Generator) 
> where
> I also had heaps of problems with, I did debug the stuff together with the 
> manufacturer's
> R&D and finally got a perfectly synced station AND a Stratum-1 NTP 
> (everything in
> double with automatic failover, a requirement for a TV-station). (Thanks to 
> lurking for 
> years as a genetically predispositioned Time-Nut, my father was a 
> watchmaker...So I 
> knew more or less what a was talking about and could prove things thanks to 
> my TBolt etc.)
> Then I did install Meinberg NTP-client on every Win machine and all was 
> suddenly 
> perfectly running, everybody happy!
> This also solved some frequent file versioning problems for storing different 
> versions of 
> videoclips especially in a mixed Win/Lin environment where Linux proved to be 
> the 
> more logical/strict way of implementation.
> 
> Another thing, being considered as the local video timenut a colleague called 
> me from
> Saudi Arabia where he was having timing problems on two locations spaced 
> 700km. apart
> where he had funny image jumps at the exact same time, both stations were 
> synced by
> each the same TCG with GPS option (same as above), could the americans jam 
> the GPS
> signals over there, somebody heard about 

Re: [time-nuts] Timing performance of servers

[lists]

The GPS seeing the horizon isn't required. Those satellites are filtered out by 
software. The timing GPSs are designed to be less sensitive to the horizon.


-Original Message-
From: Chris Albertson 
Sender: time-nuts-boun...@febo.com
Date: Thu, 25 Oct 2012 10:04:43 
To: Discussion of precise time and frequency measurement
Reply-To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Timing performance of servers

On Thu, Oct 25, 2012 at 9:44 AM, Sarah White  wrote:

> Regardless of if I run linux vs bsd vs windows (will be testing multiple
> configurations of each, and doing writeups over the next few years as I
> test more and learn) I'll need a good external antenna for the new GPS
> I'm going to run.
>
> Anyone think I can get by with anything cheaper than a symmetricom
> 58532a antenna? I can probably get one (used) for less than $50 on ebay,
> but I'd really prefer to source something more entry-level for closer to
> $5 or $10 if possible. Any suggestions?

Chris Albertson
Redondo Beach, California

Location matters a LOT more than the brand of antenna.

In an ideal world a GPS antenna needs to see all the way to the
horizon in all directions AND it needs to be far way from reflective
objects that can cause "multi path".   Some times moving a foot or
some is enough for an improvement.

You will notice that the best timing mode antenna come inside
enclosures made to shed water and snow.  They are pointy or round on
top.   You don't need this feature if the antenna is looking out a
window.  In fact the small patch type antenna might be able to be
place close to a window and get a better view of the sky.

All that said.  These are good and not expensive.  ebay #270881742870
I have one of these on a mast and the cable fits inside the pipe/mast.
the patch antenna is cheaper see #290739284641

One thing to watch is the kind of connectors.  You don't want to have
to use a chain of adaptors, N to F to BNC.   Those can cost $5 each
and certinly do not help the signal.  For outdoors I like "N" type as
they are 100% water proof.   Some types of "F" are too but not all of
them.

Watch that you get a 5V volt antenna (unless you really want a 3.5
volt type) and get a co-axial type cable.  Some have odd-ball
multi-pin cables

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Re: [time-nuts] Timing performance of servers

[Chris Albertson]

On Thu, Oct 25, 2012 at 9:44 AM, Sarah White  wrote:

> Regardless of if I run linux vs bsd vs windows (will be testing multiple
> configurations of each, and doing writeups over the next few years as I
> test more and learn) I'll need a good external antenna for the new GPS
> I'm going to run.
>
> Anyone think I can get by with anything cheaper than a symmetricom
> 58532a antenna? I can probably get one (used) for less than $50 on ebay,
> but I'd really prefer to source something more entry-level for closer to
> $5 or $10 if possible. Any suggestions?

Chris Albertson
Redondo Beach, California

Location matters a LOT more than the brand of antenna.

In an ideal world a GPS antenna needs to see all the way to the
horizon in all directions AND it needs to be far way from reflective
objects that can cause "multi path".   Some times moving a foot or
some is enough for an improvement.

You will notice that the best timing mode antenna come inside
enclosures made to shed water and snow.  They are pointy or round on
top.   You don't need this feature if the antenna is looking out a
window.  In fact the small patch type antenna might be able to be
place close to a window and get a better view of the sky.

All that said.  These are good and not expensive.  ebay #270881742870
I have one of these on a mast and the cable fits inside the pipe/mast.
the patch antenna is cheaper see #290739284641

One thing to watch is the kind of connectors.  You don't want to have
to use a chain of adaptors, N to F to BNC.   Those can cost $5 each
and certinly do not help the signal.  For outdoors I like "N" type as
they are 100% water proof.   Some types of "F" are too but not all of
them.

Watch that you get a 5V volt antenna (unless you really want a 3.5
volt type) and get a co-axial type cable.  Some have odd-ball
multi-pin cables

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Re: [time-nuts] Timing performance of servers

[Don Latham]

Look out for TNC connectors and 12v on the Symmetricons!
Don

Bob Camp
> Hi
>
> If:
>
> 1) You are in a reasonable location (good sky view)
> 2) Don't have a great long cable run (< 50')
> 3) Are only after NTP time
>
> Then, you can get away with a pretty simple antenna. I likely won't last
> as
> long as a better one out in the weather though. If you shop the auction
> sites you can get reasonable antennas (Lucent / Trimble / Syneregy)  for
> <
> $30.
>
> Bob
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Sarah White
> Sent: Thursday, October 25, 2012 12:44 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Timing performance of servers
>
> On 10/24/2012 6:47 PM, Magnus Danielson wrote:
>> Fellow time-nuts,
>>
>> When spending time on a conference last week, I heard one interesting
>> comment that they lost data due to bad timing on their Windows
>> servers.
>>
>> Now, I know that the standard Windows uses SNTP in order to achieve
>> the
>> goal of having the timing of the machines sufficiently aligned to
>> allow
>> Kerberos authentication. SNTP suffice for that, as it needs to be a
>> handful of minutes in line.
>>
>> If you need better performance than that, you should use NTP (and then
>> download and install Meinbergs Windows-client for NTP).
>>
>> Then again, I would point out that for this type of data, it would
>> most
>> probably be better served on a Linux box.
>>
>> What should be a nice wake-up call for them would be a summation of
>> how
>> different strategies would give them clock precision of sufficient
>> grade. So, does anyone know of such measurements presented anywhere?
>>
>> There are bits and pieces, but the ideal for this case would be if
>> they
>> where collected in one page/paper.
>>
>> This is an awareness thing, so that people can do a little more
>> well-informed choices.
>>
>> Cheers,
>> Magnus
>
> 1)
>
> Thanks magnus. This is something I'm quite interested in:
>
> I'm not the only one doing testing for Microsoft NT 5.x and higher
> against NTP-type synchronization. It's actually high enough quality such
> that a Windows server running NTP with a refclock provides significantly
> better time than the public NTP servers.
>
> Here are a few writeups I've been using for reference, and I've been
> testing and duplicating some of the listed configurations, hoping for my
> own writeups:
>
> http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html (basic timing)
>
> http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html (connected
> to refclock, timing was better than 50 microseconds jitter, averaging
> less than 10 microseconds)
>
> Am actively in the process of getting everything to replace my own
> "navigation" GPS refclock with a timing mode one. At this point I just
> need to find a good antenna...
>
> 2)
>
> ... Changing subject slightly:
>
> Regardless of if I run linux vs bsd vs windows (will be testing multiple
> configurations of each, and doing writeups over the next few years as I
> test more and learn) I'll need a good external antenna for the new GPS
> I'm going to run.
>
> Anyone think I can get by with anything cheaper than a symmetricom
> 58532a antenna? I can probably get one (used) for less than $50 on ebay,
> but I'd really prefer to source something more entry-level for closer to
> $5 or $10 if possible. Any suggestions?
>
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>
>
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-- 
"Neither the voice of authority nor the weight of reason and argument
are as significant as experiment, for thence comes quiet to the mind."
De Erroribus Medicorum, R. Bacon, 13th century.
"If you don't know what it is, don't poke it."
Ghost in the Shell


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com



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Re: [time-nuts] Timing performance of servers

[Bob Camp]

Hi

If: 

1) You are in a reasonable location (good sky view)
2) Don't have a great long cable run (< 50')
3) Are only after NTP time

Then, you can get away with a pretty simple antenna. I likely won't last as
long as a better one out in the weather though. If you shop the auction
sites you can get reasonable antennas (Lucent / Trimble / Syneregy)  for <
$30. 

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Sarah White
Sent: Thursday, October 25, 2012 12:44 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Timing performance of servers

On 10/24/2012 6:47 PM, Magnus Danielson wrote:
> Fellow time-nuts,
> 
> When spending time on a conference last week, I heard one interesting
> comment that they lost data due to bad timing on their Windows servers.
> 
> Now, I know that the standard Windows uses SNTP in order to achieve the
> goal of having the timing of the machines sufficiently aligned to allow
> Kerberos authentication. SNTP suffice for that, as it needs to be a
> handful of minutes in line.
> 
> If you need better performance than that, you should use NTP (and then
> download and install Meinbergs Windows-client for NTP).
> 
> Then again, I would point out that for this type of data, it would most
> probably be better served on a Linux box.
> 
> What should be a nice wake-up call for them would be a summation of how
> different strategies would give them clock precision of sufficient
> grade. So, does anyone know of such measurements presented anywhere?
> 
> There are bits and pieces, but the ideal for this case would be if they
> where collected in one page/paper.
> 
> This is an awareness thing, so that people can do a little more
> well-informed choices.
> 
> Cheers,
> Magnus

1)

Thanks magnus. This is something I'm quite interested in:

I'm not the only one doing testing for Microsoft NT 5.x and higher
against NTP-type synchronization. It's actually high enough quality such
that a Windows server running NTP with a refclock provides significantly
better time than the public NTP servers.

Here are a few writeups I've been using for reference, and I've been
testing and duplicating some of the listed configurations, hoping for my
own writeups:

http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html (basic timing)

http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html (connected
to refclock, timing was better than 50 microseconds jitter, averaging
less than 10 microseconds)

Am actively in the process of getting everything to replace my own
"navigation" GPS refclock with a timing mode one. At this point I just
need to find a good antenna...

2)

... Changing subject slightly:

Regardless of if I run linux vs bsd vs windows (will be testing multiple
configurations of each, and doing writeups over the next few years as I
test more and learn) I'll need a good external antenna for the new GPS
I'm going to run.

Anyone think I can get by with anything cheaper than a symmetricom
58532a antenna? I can probably get one (used) for less than $50 on ebay,
but I'd really prefer to source something more entry-level for closer to
$5 or $10 if possible. Any suggestions?

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Re: [time-nuts] Timing performance of servers

[Sarah White]

On 10/24/2012 6:47 PM, Magnus Danielson wrote:
> Fellow time-nuts,
> 
> When spending time on a conference last week, I heard one interesting
> comment that they lost data due to bad timing on their Windows servers.
> 
> Now, I know that the standard Windows uses SNTP in order to achieve the
> goal of having the timing of the machines sufficiently aligned to allow
> Kerberos authentication. SNTP suffice for that, as it needs to be a
> handful of minutes in line.
> 
> If you need better performance than that, you should use NTP (and then
> download and install Meinbergs Windows-client for NTP).
> 
> Then again, I would point out that for this type of data, it would most
> probably be better served on a Linux box.
> 
> What should be a nice wake-up call for them would be a summation of how
> different strategies would give them clock precision of sufficient
> grade. So, does anyone know of such measurements presented anywhere?
> 
> There are bits and pieces, but the ideal for this case would be if they
> where collected in one page/paper.
> 
> This is an awareness thing, so that people can do a little more
> well-informed choices.
> 
> Cheers,
> Magnus

1)

Thanks magnus. This is something I'm quite interested in:

I'm not the only one doing testing for Microsoft NT 5.x and higher
against NTP-type synchronization. It's actually high enough quality such
that a Windows server running NTP with a refclock provides significantly
better time than the public NTP servers.

Here are a few writeups I've been using for reference, and I've been
testing and duplicating some of the listed configurations, hoping for my
own writeups:

http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html (basic timing)

http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html (connected
to refclock, timing was better than 50 microseconds jitter, averaging
less than 10 microseconds)

Am actively in the process of getting everything to replace my own
"navigation" GPS refclock with a timing mode one. At this point I just
need to find a good antenna...

2)

... Changing subject slightly:

Regardless of if I run linux vs bsd vs windows (will be testing multiple
configurations of each, and doing writeups over the next few years as I
test more and learn) I'll need a good external antenna for the new GPS
I'm going to run.

Anyone think I can get by with anything cheaper than a symmetricom
58532a antenna? I can probably get one (used) for less than $50 on ebay,
but I'd really prefer to source something more entry-level for closer to
$5 or $10 if possible. Any suggestions?

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Re: [time-nuts] SR620 VCTCXO replacement

[Ed Palmer]

K1602TE (note the different part number) oscillators have been sold on 
ebay in the past.  Keep an eye out there in case more appear. You could 
also contact the people who sold them and see if they have one or two 
more lurking in the corners.


Other than that, it's just a TCXO that uses the same pinout as all the 
others.  Match the specs ( or maybe a better one is available today ) 
and drop it in.


Ed

On 10/25/2012 9:36 AM, Eric Garner wrote:

I have an SR620 that I was preparing to sell. It's been clocked by an
external 10 Mhz source for the whole time I've owned it so I wanted to
verify that the internal VCTCXO was still up to snuff. after CALing
the internal reference I set it up to monitor the output from my Tbolt
and it started drifting. the drift was bad enough that I started to
investigate. The internal reference was wandering around by as much as
60 Hz over the course of 10 min. monitoring the EFC voltage at R343
indicated that there was not so much as a mV change during that time.
this has led me to the conclusion that the XO on the board is suspect.

The MtronPTI K1601TE that's on the board is EOL and the replacements
don't seem to be stocked at any of the disti's listed on Mtron's
website that I've checked so far. I've not started the search for ,
Does anyone have any suggestions for replacements?



--Eric
_
Eric Garner


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Re: [time-nuts] SR620 VCTCXO replacement

[Bob Camp]

Hi

Chances of finding that in distribution are near zero. Best approach is to
find a part with the same pin out / frequency / supply / EFC / stability on
an auction site. Since it's a 5V / 14 pin DIP that should be possible. 

Another simple fix would be a distributor stock miniature VCTCXO and a small
carrier board. 

Bob 

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Eric Garner
Sent: Thursday, October 25, 2012 11:36 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] SR620 VCTCXO replacement

I have an SR620 that I was preparing to sell. It's been clocked by an
external 10 Mhz source for the whole time I've owned it so I wanted to
verify that the internal VCTCXO was still up to snuff. after CALing
the internal reference I set it up to monitor the output from my Tbolt
and it started drifting. the drift was bad enough that I started to
investigate. The internal reference was wandering around by as much as
60 Hz over the course of 10 min. monitoring the EFC voltage at R343
indicated that there was not so much as a mV change during that time.
this has led me to the conclusion that the XO on the board is suspect.

The MtronPTI K1601TE that's on the board is EOL and the replacements
don't seem to be stocked at any of the disti's listed on Mtron's
website that I've checked so far. I've not started the search for ,
Does anyone have any suggestions for replacements?



--Eric
_
Eric Garner

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[time-nuts] SR620 VCTCXO replacement

[Eric Garner]

I have an SR620 that I was preparing to sell. It's been clocked by an
external 10 Mhz source for the whole time I've owned it so I wanted to
verify that the internal VCTCXO was still up to snuff. after CALing
the internal reference I set it up to monitor the output from my Tbolt
and it started drifting. the drift was bad enough that I started to
investigate. The internal reference was wandering around by as much as
60 Hz over the course of 10 min. monitoring the EFC voltage at R343
indicated that there was not so much as a mV change during that time.
this has led me to the conclusion that the XO on the board is suspect.

The MtronPTI K1601TE that's on the board is EOL and the replacements
don't seem to be stocked at any of the disti's listed on Mtron's
website that I've checked so far. I've not started the search for ,
Does anyone have any suggestions for replacements?



--Eric
_
Eric Garner

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Re: [time-nuts] Timing performance of servers

[Rob Kimberley]

Thanks for that David.

Rob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of David J Taylor
Sent: 25 October 2012 09:51
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Timing performance of servers

http://www.meinberg.de/english/sw/ntp.htm

You can get NTP for windows and also their NTP Monitor. 

Free download.

Rob Kimberley
=

.. with user-oriented install instructions here:

  http://www.satsignal.eu/ntp/setup.html

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk

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Re: [time-nuts] Adjusting HP 5065A frequency

[Bob Camp]

Hi

If you have a divide that's "inside" the range of the DAC, there are no
nasty spurs (just DAC spurs). Once you are outside that range, there's a
stepped triangle wave modulating the carrier. You get all the sidebands that
you would expect from that very low frequency modulation. If the DAC is less
than perfect it will toss in it's own "helpful stuff" as well.

It's not quite that simple of course. You have a dac width, a sine lookup
table size / resolution and a phase accumulator width. You can also dither
things. The stuff above will at least get you pointed in the right
direction. 

Bob 

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Hal Murray
Sent: Thursday, October 25, 2012 12:45 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Adjusting HP 5065A frequency


li...@rtty.us said:
> The gotcha with the DDS is phase truncation. That pretty much trashes the
> ADEV. 

Thanks.

How should I think about the output of a DDS?

Lets assume I'm interested in the frequency domain where the "error" is 
measured in phase noise.  For a DDS, I think they are spurs.

Suppose I have a clock running at 101 MHz and I want 10 MHz.  Is the output 
10 MHz with some spurs, or 10.1 MHz with some spurs?

Are there rules of thumb for the size and location of the spurs?  (given the

input freq and output freq)


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] 5 MHz Racal MA259 / / Sulzer Crystal Oscillator

[Bob Camp]

Hi

I have a GR rack mount OCXO of the same vintage. It took a couple of months
to settle to a reasonable aging rate. 

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Adrian
Sent: Wednesday, October 24, 2012 8:45 PM
To: Time-Nuts
Subject: [time-nuts] 5 MHz Racal MA259 / / Sulzer Crystal Oscillator

Hello,

recently I couldn't resist to acquire one of these Racal MA259 units 
with a SA 500 crystal oscillator which was designed by Sulzer.
What a beautiful piece of ancient high precision laboratory gear!

Well, it wasn't claimed to still meet the specifications, but it was at 
least in a working condition.
First I was surprised about the high frequency drift that was about 50 
times as high as specified, that is, a few 1E-8's rather than the 
impatiently awaited 5E-10 per day.
I could however observe the drift slowly getting down, and, after 
reading the manual, I was less concerned as it pointed out that the 
specified accuracy can be expected to be met after a full month of 
continuous operation. That was before I realized that the inner oven 
wasn't heating at all, and its temperature being low by a few degrees.

So, I gotta have a look inside that huge cylinder with the large dewar 
flask inside. Unfortunately, the toroid transformer of the temperature 
bridge had developed a short beween the primary and secondary windings. 
I could burn the short out, but there is now some noise visible on the 
meter needle as well as, much slower of course, on the frequency 
stability plot. There might still be some conductivity left between the 
windings, or something else is noisy.

Next I noticed that the meter reading of the oscillator amplitude was 
quite a bit off. I was already suspecting those infamous carbon 
composite resistors might have drifted as usual. So, I decided to 
replace every resistor in the oscillator, the buffer / amplitude control 
stage and the inner oven. Indeed, several of the resistors that set the 
oscillator amplitude were drifted by up to 100 percent and were even 
noisy on the ohmmeter. Probably not that great for a ultra high 
precision circuit... Well, ahould I have replaced the capacitors, too??

Now the amplitude is right, and the drift is starting to settle again. 
For the time being, I want to see how it stabilizes. Then come the next 
project to take care of the inner oven noise, and to fix the 100 kHz 
divider that has stopped working.

Is there any information about the Sulzer desiagn available? Anyone who 
repaired one of these oscillators?

Adrian



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[time-nuts] Re timing performance of (windows) servers

[Mark Spencer]

In my experience (in my day job) many / most timing issues with widows pc's and 
servers revolve around the sync method breaking (and often the failure not 
being detected) rather than accuracy issues when the sync method is working.  
As Magnus pointed out authentication methods such as Kerberos require a time 
accuracy with a few minutes (iirc the default windows 2008 server config 
requires time to be synced within 5 min for Kerberos to work.).  A lack of time 
sync can cause this threshold to be reached surprisingly quickly.

Virtual servers also may also introduce their own issues into this process.  

Here is a link to a kbase article from VMware that may give some insight into 
some of these potential issues (re VMware.)


http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1318

If anyone wants to discuss this further I'd be happy to do so off list, but I'm 
on course in Brazil this week so there may be some delays (:


Regards Mark Spencer



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Re: [time-nuts] Timing performance of servers

[Bob Camp]

Hi

Judah Levine (probably spelled his name wrong) from NIST has a series of papers 
on this. They go back into the 90's.

Bob
 
On Oct 24, 2012, at 6:47 PM, Magnus Danielson  
wrote:

> Fellow time-nuts,
> 
> When spending time on a conference last week, I heard one interesting comment 
> that they lost data due to bad timing on their Windows servers.
> 
> Now, I know that the standard Windows uses SNTP in order to achieve the goal 
> of having the timing of the machines sufficiently aligned to allow Kerberos 
> authentication. SNTP suffice for that, as it needs to be a handful of minutes 
> in line.
> 
> If you need better performance than that, you should use NTP (and then 
> download and install Meinbergs Windows-client for NTP).
> 
> Then again, I would point out that for this type of data, it would most 
> probably be better served on a Linux box.
> 
> What should be a nice wake-up call for them would be a summation of how 
> different strategies would give them clock precision of sufficient grade. So, 
> does anyone know of such measurements presented anywhere?
> 
> There are bits and pieces, but the ideal for this case would be if they where 
> collected in one page/paper.
> 
> This is an awareness thing, so that people can do a little more well-informed 
> choices.
> 
> Cheers,
> Magnus
> 
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Re: [time-nuts] time-nuts Digest, Vol 99, Issue 111

[Jacques Tiete]

Hello Magnus,

I know what you're talking about, I'm working for a company specialized in 
broadcasting (from studio's to stations to satellites...) and in this world 
correct 
timing is paramount, we live by the 1/25 second rythm and even less if you 
have to sync on a line in the image ;-).
Some time ago we were instaling a complete TV station and had huge problems
with image stability and also especially the correct starting time of a clip or 
transmission.
Nobody wants to start his newsreel at eg. 20:00:05;23... it must be 20:00:00;00
We were looking into this and noticed that the customers servers (Win!) where 
synced by SNTP, this is plain c..p!
Have a look @ http://technet.microsoft.com/en-us/library/cc773013(WS.10).aspx
Especially where it says:
"Important 
 The W32Time service is not a full-featured NTP solution that meets 
time-sensitive 
application needs and is NOT SUPPORTED by Microsoft as such. For more 
information, 
see Microsoft Knowledge Base article 939322, Support boundary to configure the 
Windows Time service for high-accuracy environments."

Also have a look @ http://support.microsoft.com/kb/939322
It says:
"We do not guarantee and we do not support the accuracy of the W32Time service 
between nodes on a network. The W32Time service is not a full-featured NTP 
solution
 that meets time-sensitive application needs. The W32Time service is primarily 
designed to do the following:
Make the Kerberos version 5 authentication protocol work.
Provide loose sync time for client computers.
The W32Time service cannot reliably maintain sync time to the range of 1 to 2 
seconds. 
Such tolerances are outside the design specification of the W32Time service."

So it is...   1 to 2 seconds

Our video playout servers are decent super stable units that use heaps of 
Xilinx FPGA's
for coding/decoding videostreams supervised by a mil-spec VXworks OS, it uses 
the 
so-called LTC for synchronising the playout, implemented mostly in hardware so
I did not suspect our machines. I did install a new TCG (TimeCode Generator) 
where
I also had heaps of problems with, I did debug the stuff together with the 
manufacturer's
R&D and finally got a perfectly synced station AND a Stratum-1 NTP (everything 
in
double with automatic failover, a requirement for a TV-station). (Thanks to 
lurking for 
years as a genetically predispositioned Time-Nut, my father was a 
watchmaker...So I 
knew more or less what a was talking about and could prove things thanks to my 
TBolt etc.)
Then I did install Meinberg NTP-client on every Win machine and all was 
suddenly 
perfectly running, everybody happy!
This also solved some frequent file versioning problems for storing different 
versions of 
videoclips especially in a mixed Win/Lin environment where Linux proved to be 
the 
more logical/strict way of implementation.

Another thing, being considered as the local video timenut a colleague called 
me from
Saudi Arabia where he was having timing problems on two locations spaced 700km. 
apart
where he had funny image jumps at the exact same time, both stations were 
synced by
each the same TCG with GPS option (same as above), could the americans jam the 
GPS
signals over there, somebody heard about this? It could be a real problem for 
us, we 
may need to use another method for station timing (Rb maybe, with some regular 
syncing
etc.)

Sorry for my long message but I don't often send timenut mail and this is a 
good example
of some real-life timenutting ;-)

I also have here a nice BeagleBone mini Linux board resting, where I would want 
to install 
a FreeBSD image on and implement a NTP with a promising GPS board from Adafruit,
something for the long and cosy winter evenings... :-)


Best regards,

Jacques Tiete




From: Magnus Danielson 
To: Time-Nuts 
Subject: [time-nuts] Timing performance of servers
Message-ID: <50887008.3030...@rubidium.dyndns.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Fellow time-nuts,

When spending time on a conference last week, I heard one interesting 
comment that they lost data due to bad timing on their Windows servers.

Now, I know that the standard Windows uses SNTP in order to achieve the 
goal of having the timing of the machines sufficiently aligned to allow 
Kerberos authentication. SNTP suffice for that, as it needs to be a 
handful of minutes in line.

If you need better performance than that, you should use NTP (and then 
download and install Meinbergs Windows-client for NTP).

Then again, I would point out that for this type of data, it would most 
probably be better served on a Linux box.

What should be a nice wake-up call for them would be a summation of how 
different strategies would give them clock precision of sufficient 
grade. So, does anyone know of such measurements presented anywhere?

There are bits and pieces, but the ideal for this case would be if they 
where collected in one page/paper.

This is an awareness thing, so that people can do a littl

Re: [time-nuts] Timing performance of servers

[David J Taylor]

http://www.meinberg.de/english/sw/ntp.htm

You can get NTP for windows and also their NTP Monitor. 


Free download.

Rob Kimberley
=

.. with user-oriented install instructions here:

 http://www.satsignal.eu/ntp/setup.html

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk

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Re: [time-nuts] Timing performance of servers

[Rob Kimberley]

http://www.meinberg.de/english/sw/ntp.htm

You can get NTP for windows and also their NTP Monitor. 

Free download.

Rob Kimberley

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Edgardo Molina
Sent: 25 October 2012 01:05
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Timing performance of servers

Dear Mangus,

I will allow myself to share a comment on your thread. 

Timing on windows servers is not one of their plausible strengths. It was
clearly pointed out during the SIM conference last week at CENAM. In fact
there was an interesting discussion about the drawbacks when using NTP
Windows based servers and all kind of NTP appliances compared to full size
Linux based NTP servers. The example of what NIST is using nationwide for
their servers set an example of good server hardware and linux to provide
the nation's NTP pulse.

I haven't done any experiments with Windows for NTP services, still it could
be interesting as to set a benchmark while comparing it to the Linux boxes.

I am currently trying out the Domain Time II NTP client from Symmetricom for
the thesis. I have to come back to Symmetricom's Miguel García to decide on
purchasing a Domain Time II NTP client kit.  How is the Mainberg NTP client
different from the Symmetricom version? Have you tried both? If not I will
be more than glad to help comparing both if you can help me pointing out the
source for a demo version of Mainberg's software. Maybe then an objective
review of both clients will be in order, I will be more than glad to do it
or to test them against Windows NTP services, appliances and/or Linux NTP
boxes. I have at least an example of those at the office.

-13
Just my  2x10   cents.


Regards to you and the group,



Edgardo Molina
Dirección IPTEL

www.iptel.net.mx

T : 55 55 55202444
M : 04455 20501854

Piensa en Bits SA de CV



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On Oct 24, 2012, at 5:47 PM, Magnus Danielson 
wrote:

> Fellow time-nuts,
> 
> When spending time on a conference last week, I heard one interesting
comment that they lost data due to bad timing on their Windows servers.
> 
> Now, I know that the standard Windows uses SNTP in order to achieve the
goal of having the timing of the machines sufficiently aligned to allow
Kerberos authentication. SNTP suffice for that, as it needs to be a handful
of minutes in line.
> 
> If you need better performance than that, you should use NTP (and then
download and install Meinbergs Windows-client for NTP).
> 
> Then again, I would point out that for this type of data, it would most
probably be better served on a Linux box.
> 
> What should be a nice wake-up call for them would be a summation of how
different strategies would give them clock precision of sufficient grade.
So, does anyone know of such measurements presented anywhere?
> 
> There are bits and pieces, but the ideal for this case would be if they
where collected in one page/paper.
> 
> This is an awareness thing, so that people can do a little more
well-informed choices.
> 
> Cheers,
> Magnus
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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