[time-nuts] A new time nut - and a question!

[Christopher Glass]

Hi list,

I recently got time to build my first stratum-1 GPS timeserver around
a raspberry-pi (first model) and one of these [1].
I would ideally like to have it work as a completely standalone time
source, only getting timing information from the GPS signal it is
receiving (no network peers). As such, I built ntpd with --with-NMEA,
and tweaked things around to the point where I *think* I got it
working, however, my simple question is:

Can somebody tell me whether it's *actually* working? :)

The output I get from "ntpq -c pe -c as -c rl" on the system [2] is
confusing me a little since I see the GPS source being selected as
sys_peer, but the event showing says "no_sys_peer". Is this expected
in case no network source is available?

The last section of the output furthermore shows a difference between
the "reftime" and "clock" fields. Should I understand that reftime is
the GPS time and "clock" the state of the system clock? In that case,
should I see the clocks converge over time?

I apologize if these are easily answered by reading a manual somewhere
- like I said, it's my very first venture in the world of timekeeping,
and I would benefit from having somebody explain things to me.

Thanks for your time

- Chris


Links:
-
[1]: 
http://ava.upuaut.net/store/index.php?route=product/product=59_60_id=95
[2]: http://pastebin.ubuntu.com/12631346/
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Re: [time-nuts] SRS FS710 spurs at 50Hz and harmonics?

[John Miles]

SRS likes to isolate their RF connectors from ground, it seems.  This is almost 
never a good idea.  When measuring PRS10 Rb standards, I've seen similar line 
spurs that went away when I grounded one side of the balanced 10 MHz output at 
the point where the DC supply was connected to the unit.   

Looking at the schematic that Orin posted earlier, it seems they've done the 
same thing with the FS710.  Try bonding the insulated BNC input jack to ground 
at the point where it enters the chassis, and I'll bet those spurs get a lot 
better.  (That is, unless you actually do have a bad filter capacitor.)

-- john, KE5FX
Miles Design LLC

> > I seem to get very strong spurs at 50Hz and harmonics with an old
> > second-hand SRS FS710:
> > http://www.anderswallin.net/2015/09/srs-fs710-noise-measurement/
> > feature or bug? Anyone looked at the powersupply and figured out what parts
> > to change?
> 
> If you live in a country with 50 Hz mains network then this sounds like
> a dead capacitor in the power supply...

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Re: [time-nuts] A new time nut - and a question!

[David J Taylor]

Hi list,

I recently got time to build my first stratum-1 GPS timeserver around
a raspberry-pi (first model) and one of these [1].
I would ideally like to have it work as a completely standalone time
source, only getting timing information from the GPS signal it is
receiving (no network peers). As such, I built ntpd with --with-NMEA,
and tweaked things around to the point where I *think* I got it
working, however, my simple question is:

[]
Thanks for your time

- Chris
===

Chris,

I used no special build on NTP.  I've been asked the same question, and put 
some notes sent in by users on my Web site:


 http://www.satsignal.eu/ntp/Raspberry-Pi-quickstart.html#stand-alone

Perhaps there's something there?

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] A new time nut - and a question!

[Brian Inglis]

On 2015-10-01 06:05, Christopher Glass wrote:

Hi list,

I recently got time to build my first stratum-1 GPS timeserver around
a raspberry-pi (first model) and one of these [1].
I would ideally like to have it work as a completely standalone time
source, only getting timing information from the GPS signal it is
receiving (no network peers). As such, I built ntpd with --with-NMEA,
and tweaked things around to the point where I *think* I got it
working, however, my simple question is:

Can somebody tell me whether it's *actually* working? :)

The output I get from "ntpq -c pe -c as -c rl" on the system [2] is
confusing me a little since I see the GPS source being selected as
sys_peer, but the event showing says "no_sys_peer". Is this expected
in case no network source is available?

The last section of the output furthermore shows a difference between
the "reftime" and "clock" fields. Should I understand that reftime is
the GPS time and "clock" the state of the system clock? In that case,
should I see the clocks converge over time?

I apologize if these are easily answered by reading a manual somewhere
- like I said, it's my very first venture in the world of timekeeping,
and I would benefit from having somebody explain things to me.


Have you looked at: http://ava.upuaut.net/?p=726

Have you run the GPS module in one place long enough to do a survey
and set it into Stationary mode?

Is PPS enabled and being received?
Have you specified 'prefer' on your server conf line to provide
a time stamp for PPS?
Have you configured a drift file to save frequency and speed up restart?

Have you enabled logging with 'logconfig =allall'?
Check your syslog with dmesg and see what messages have been
or are being issued - there aren't many, except at startup,
even with a bunch of network peers or servers configured:
most are network issues also logged in protostats (below).
More details at: http://www.ntp.org/ntpfaq/NTP-s-trouble.htm

Your pastebin shows:

remote   refid  st t when poll reach   delay   offset  jitter
==
*GPS_NMEA(0) .GPS.0 l3   1670.000   -0.040   0.043

reach is only 7 - 3 samples - needs 8 samples - 377 - to prime the filters
offset 40us and jitter 43us is higher than expected - should be low us


associd=0 status=c418 leap_alarm, sync_uhf_radio, 1 event, no_sys_peer,
version="ntpd 4.2.6p5@1.2349-o Sat Sep 26 08:08:22 UTC 2015 (1)",
processor="armv6l", system="Linux/4.1.7+", leap=11, stratum=1,

leap_alarm and leap=11 say unsynced - should be leap_none and leap=00


precision=-20, rootdelay=0.000, rootdisp=1937.748, refid=GPS,

rootdisp=1937.748 is really high - should be less than 0.5


reftime=d9b79166.599b08f6 Thu, Oct 1 2015 13:03:02.350,
clock=d9b79169.f52bbe6f Thu, Oct 1 2015 13:03:05.957, peer=33608, tc=4,

reftime is the last ref clock time used - clock is just the current time


mintc=3, offset=0.000, frequency=-27.210, sys_jitter=0.043,

offset=0.000 says the system time is not yet set - should be low us
frequency=-27.210 has to stay within 1ppm for it to be an accurate
estimate of your system clock drift - may take some time to settle


clk_jitter=0.015, clk_wander=0.000

clk_jitter=0.015, clk_wander=0.000 look good - low us and zero

Add ntpq '-c cv' to see your reference clock variables which
should look like:
  associd=0 status=0011 , 1 event, clk_no_reply,
  device="NMEA GPS Clock",
  
timecode="$GPRMC,154611,A,5108.3494,N,11411.5630,W,000.0,000.0,011015,014.7,E,D*0E",
  poll=43905, noreply=1, badformat=0, baddata=0, fudgetime1=0.000,
  stratum=0, refid=GPS, flags=0
A few event counts are normal at startup - high means comms problems!

More details on all this at: 
https://www.eecis.udel.edu/~mills/ntp/html/ntpq.html

Have you created and defined 'statsdir /var/log/ntp/' and
'statistics clockstats loopstats peerstats protostats sysstats'
to record and monitor operation?
'filegen' is not required with default UTC day file dating and rollover.
More details at: https://www.eecis.udel.edu/~mills/ntp/html/monopt.html

If you have network routing, a few good servers close by, or a country
'pool CC.pool.ntp.org iburst' conf will keep your system from becoming
a falseticker if there are any GPS issues.

Email off list if you need more info.
--
Take care. Thanks, Brian Inglis
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Re: [time-nuts] A new time nut - and a question!

[Christopher Glass]

Hi David,

Thanks for the pointer - but the driver I am using is type 20 (NMEA),
so that flag1 is documented as enabling/disabling of PPS signal
processing instead.

After some time, the output of "ntpq -c pe -c as -c rl" seemed to
stabilize as [1]. The GPS reference seems to be used correctly (as
show by the leading "o" in ntpq -c pe" output.

However I still don't understand the "reftime/clock" difference, and
it seems the two dates are drifting from each other rather than
converging, which is unexpected (to me, as a newbie).
The frequency field keeps changing, so should I understand that the
frequency field is adjusted automatically until the times are in sync?

[1]: http://pastebin.ubuntu.com/12632650/

On Thu, Oct 1, 2015 at 6:02 PM, David J Taylor
 wrote:
> Hi list,
>
> I recently got time to build my first stratum-1 GPS timeserver around
> a raspberry-pi (first model) and one of these [1].
> I would ideally like to have it work as a completely standalone time
> source, only getting timing information from the GPS signal it is
> receiving (no network peers). As such, I built ntpd with --with-NMEA,
> and tweaked things around to the point where I *think* I got it
> working, however, my simple question is:
>
> []
> Thanks for your time
>
> - Chris
> ===
>
> Chris,
>
> I used no special build on NTP.  I've been asked the same question, and put
> some notes sent in by users on my Web site:
>
>  http://www.satsignal.eu/ntp/Raspberry-Pi-quickstart.html#stand-alone
>
> Perhaps there's something there?
>
> 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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[time-nuts] New Symmetricom 58532A antennas - Launch3

[Gregory Beat]

I received this e-mail earlier today (below) from Launch3.
Launch3 has been selling surplus/overstock cellular/telecom equipment.
They currently have a LARGE supply (~750) of surplus Symmetricom 58532A 
antennas.

Symmetricom 58532A GPS Antenna -- Datasheet
http://www.microsemi.com/document-portal/doc_view/133381-58532a

I acquired one of these antennas 2 weeks ago, they are brand new in box.
My 58532A antenna is currently connected to a Symmetricom/Datum TS2100 GPS 
w/Heol N024 receiver upgrade.

Check their web site and contact them (web page info), with number you desire, 
so they can determined shipping charges.

Greg
w9gb

From: Launch3

Hello
 
You previously purchased or inquired about the Symmetricom 58532A GPS Antennas, 
we are currently liquating all 750 of them.
They are all New in Box and the price is $25 each + Shipping

Link to the part -  https://www.launch3telecom.com/symmetricom/58532a.html
 
Launch3Telecom.com
Launch3Services.com
27 Daniel Rd.
Fairfield, New Jersey 07004 

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Re: [time-nuts] New Symmetricom 58532A antennas - Launch3

[Jason Ball]

Thank you ;)

On Fri, Oct 2, 2015 at 5:19 AM, Gregory Beat  wrote:

> I received this e-mail earlier today (below) from Launch3.
> Launch3 has been selling surplus/overstock cellular/telecom equipment.
> They currently have a LARGE supply (~750) of surplus Symmetricom 58532A
> antennas.
>
> Symmetricom 58532A GPS Antenna -- Datasheet
> http://www.microsemi.com/document-portal/doc_view/133381-58532a
>
> I acquired one of these antennas 2 weeks ago, they are brand new in box.
> My 58532A antenna is currently connected to a Symmetricom/Datum TS2100 GPS
> w/Heol N024 receiver upgrade.
>
> Check their web site and contact them (web page info), with number you
> desire,
> so they can determined shipping charges.
>
> Greg
> w9gb
> 
> From: Launch3
>
> Hello
>
> You previously purchased or inquired about the Symmetricom 58532A GPS
> Antennas, we are currently liquating all 750 of them.
> They are all New in Box and the price is $25 each + Shipping
>
> Link to the part -  https://www.launch3telecom.com/symmetricom/58532a.html
>
> Launch3Telecom.com
> Launch3Services.com
> 27 Daniel Rd.
> Fairfield, New Jersey 07004
>
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>



-- 
--
Teach your kids Science, or somebody else will :/

ja...@ball.net
vk2...@google.com 
callsign: vk2vjb
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Re: [time-nuts] New Symmetricom 58532A antennas - Launch3

[Bryan _]

How does the 58532A compare to some of the other antennas out there like the 
Nokia 470290. Right out of the box the Symmetricom has a >30db vs the >20db of 
the Nokia.

-=Bryan=-

> From: w...@icloud.com
> Date: Thu, 1 Oct 2015 14:19:23 -0500
> To: time-nuts@febo.com
> Subject: [time-nuts] New Symmetricom 58532A antennas - Launch3
> 
> I received this e-mail earlier today (below) from Launch3.
> Launch3 has been selling surplus/overstock cellular/telecom equipment.
> They currently have a LARGE supply (~750) of surplus Symmetricom 58532A 
> antennas.
> 
> Symmetricom 58532A GPS Antenna -- Datasheet
> http://www.microsemi.com/document-portal/doc_view/133381-58532a
> 
> I acquired one of these antennas 2 weeks ago, they are brand new in box.
> My 58532A antenna is currently connected to a Symmetricom/Datum TS2100 GPS 
> w/Heol N024 receiver upgrade.
> 
> Check their web site and contact them (web page info), with number you 
> desire, 
> so they can determined shipping charges.
> 
> Greg
> w9gb
> 
> From: Launch3
> 
> Hello
>  
> You previously purchased or inquired about the Symmetricom 58532A GPS 
> Antennas, we are currently liquating all 750 of them.
> They are all New in Box and the price is $25 each + Shipping
> 
> Link to the part -  https://www.launch3telecom.com/symmetricom/58532a.html
>  
> Launch3Telecom.com
> Launch3Services.com
> 27 Daniel Rd.
> Fairfield, New Jersey 07004 
> 
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Re: [time-nuts] New Symmetricom 58532A antennas - Launch3

[Daniel Watson]

Thanks for passing this along. That's quite a good price, assuming the shipping 
is reasonable.

Is the 38dB of gain a little "hot" for some receivers?

Dan

> On Oct 1, 2015, at 3:19 PM, Gregory Beat  wrote:
> 
> I received this e-mail earlier today (below) from Launch3.
> Launch3 has been selling surplus/overstock cellular/telecom equipment.
> They currently have a LARGE supply (~750) of surplus Symmetricom 58532A 
> antennas.
> 
> Symmetricom 58532A GPS Antenna -- Datasheet
> http://www.microsemi.com/document-portal/doc_view/133381-58532a
> 
> I acquired one of these antennas 2 weeks ago, they are brand new in box.
> My 58532A antenna is currently connected to a Symmetricom/Datum TS2100 GPS 
> w/Heol N024 receiver upgrade.
> 
> Check their web site and contact them (web page info), with number you 
> desire, 
> so they can determined shipping charges.
> 
> Greg
> w9gb
> 
> From: Launch3
> 
> Hello
> 
> You previously purchased or inquired about the Symmetricom 58532A GPS 
> Antennas, we are currently liquating all 750 of them.
> They are all New in Box and the price is $25 each + Shipping
> 
> Link to the part -  https://www.launch3telecom.com/symmetricom/58532a.html
> 
> Launch3Telecom.com
> Launch3Services.com
> 27 Daniel Rd.
> Fairfield, New Jersey 07004 
> 
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Re: [time-nuts] Z3805A as source for NTPd?

[Hal Murray]

> $ sudo ldattach -d -s 9600 -n -8 -1 pps /dev/ttyUSB0

I assume you realize that PPS over USB isn't going to work well.  (at least 
by time-nuts standards)

There is also the opportunity for hanging-bridge type quirks.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] SRS FS710 spurs at 50Hz and harmonics?

[Esa Heikkinen]

Anders Wallin kirjoitti:


I seem to get very strong spurs at 50Hz and harmonics with an old
second-hand SRS FS710:
http://www.anderswallin.net/2015/09/srs-fs710-noise-measurement/
feature or bug? Anyone looked at the powersupply and figured out what parts
to change?


If you live in a country with 50 Hz mains network then this sounds like 
a dead capacitor in the power supply. Usually this means that it has old 
fashioned linear power supply (with classic iron transformer). In that 
case, replace the secondary capacitors after the rectifier bridge(s). 
Check voltages with oscilloscope if you wanna see which ones, but it 
might be good idea to replace them all (there should't be many of them).


Should be very easy to fix.

--
73s!
Esa
OH4KJU
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Re: [time-nuts] KS-24361 REF-0 standalone

[Daniel Watson]

Hi,

Here's a little progress report on my REF-0 project. Though there hasn't
been a lot of activity in this thread recently, I do hope that some more
people have successfully gotten their REF-0s up and running.

My goal all along has been to retrofit a modern GPS into the REF-0. Over
the past couple of months I've designed a few small boards and gotten much
closer to a solution I'll be happy with. I first turned a prototype I
previously posted about into a PCB. That worked fine and installed in the
REF-0 without issues. Here is the write-up:

http://syncchannel.blogspot.com/2015/09/custom-pcb-for-ks-24361-ref-0.html

I also made a small breakout board for the U-blox NEO-6M GPS module in
order to test my layout. That worked extremely well, and allowed me to
proceed with a larger integrated design. You can find a post about that on
my blog if you are curious.

Recently, I finished the design of a complete GPS retrofit board. It is the
size of an Oncore GPS and mounts just like one in the REF-0. I am calling
it the Denuo GPS. All power and signalling goes through a header, so there
are no jumper wires internally or externally. The GPS module is the NEO-6M.
Combined with a small dongle I made for the interface connector, it creates
an almost plug-and-play solution for a GPS retrofit in the REF-0. You can
see a render of the board in the link below. I am looking forward to
getting those PCBs back and doing some testing.

http://syncchannel.blogspot.com/2015/09/sneak-peek.html

I have a lot more to talk about, especially in regards to the choice of the
GPS module and timing features versus cost. I also have at least two other
board variations I am working on. One will be a step down in complexity,
essentially making the REF-0 a cleanup oscillator for Rubidium standards
and the like. There will also be a more advanced board with a higher grade
of GPS module and some really cool features to enable GPSDO
experimentation. But I will save all of that for another day and another
post.

More to come.


Thanks,

Dan W.
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