Re: [time-nuts] 58503A VS SR625

[Anton Moehammad via time-nuts]

 Hi All,
Thank You for respond.Yes I will make 58503A to 58503A comparison but my 
problem are I got difficulties found the suitable setting for my SR620 to do it 
if any one can give a hint about proper setting for SR620 time interval setup I 
will happy to follow it. I like to have 10MHz out comparison and 1PPS 
comparison too.my Antena is 30m above ground and according to Lady Heather I my 
worst S/N is 35dB all time 
Pada Senin, 28 Mei 2018 21.17.25 GMT+7, Bob kb8tq <kb...@n1k.org> menulis:  
 
 Hi

If you are seeing 0.3 ppb delta between various HP GPSDO’s the first question 
would be “on for how long? / under what conditions?".  The HP devices take a 
*long* time 
to settle in ( like weeks ) to their final best performance loop settings. To 
fully settle, they need to be locked the whole time. Staying locked means an 
antenna that has a 
good satellite view and the unit having a solid survey location. If they are 
dropping out of lock from time to time, they will never really settle. 

Once settled, you still have a noise process. ADEV is one way to plot this sort 
of noise. Your results will still depend on the gate time on your counter(s) 
since that impacts 
how you “see” the noise.  A very short gate will give you more variation than a 
longer gate. Put another way, “tau” is part of any frequency measurement, even 
if ADEV is 
not being calculated. 

Bob

> On May 28, 2018, at 8:25 AM, Anton Moehammad via time-nuts 
> <time-nuts@febo.com> wrote:
> 
> Hi All, I have 5 pcs 58503A with various firmware and 3 of them have 8 
> channel recv and 2 have 6 channel receiver all is working but I found none of 
> 5 has same result I mean when I compare it with my SR625 use SR620 or my 
> CNT-90 use timelab there is a variation in the output.the variation about 3 
> E-9 Hz. yes use same cable and same antenna, I also monitor the temp and I 
> sure the temp variation is very minimal.any one has explanation about this 
> ?Thank YouAnton
> 
> |  | Virus-free. www.avg.com  |
> 
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[time-nuts] 58503A VS SR625

[Anton Moehammad via time-nuts]

Hi All, I have 5 pcs 58503A with various firmware and 3 of them have 8 channel 
recv and 2 have 6 channel receiver all is working but I found none of 5 has 
same result I mean when I compare it with my SR625 use SR620 or my CNT-90 use 
timelab there is a variation in the output.the variation about 3 E-9 Hz. yes 
use same cable and same antenna, I also monitor the temp and I sure the temp 
variation is very minimal.any one has explanation about this ?Thank YouAnton

|  | Virus-free. www.avg.com  |

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[time-nuts] 4046 replacement

[Anton Moehammad via time-nuts]

Hi All, I interested in discussion about 4046, in lars GPSDO he use 4046 as 
phase comparator must I replace this Chip for CD74HCT4046A btw I also have many 
TC5081 I wonder how to test the circuit use this chip if have same problem with 
4046.Thank YouAnton
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[time-nuts] Piezo Crystal Company

[Anton Moehammad via time-nuts]

Hi,I am looking for datasheet of my piezo crystal company OCXO model 2930175 
with freq 10.000MHz.in case someone has pin out its also helpful.Thank You 
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[time-nuts] Corby Watson Super 5065a work can I use a miniature Rubidium

[Anton Moehammad via time-nuts]

Hi all,a few day ago I read "super HP5065A" from Mr Corby and I wondering if 
any one has done same thing with "telecom" Rubidium pack ? I found an optical 
bandpass filter cost is cheap enough to a third country people like me but if 
any one has tried before and know a lot more than what I know I really 
appreciate if You can share it 
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[time-nuts] Bls: time-nuts Digest, Vol 148, Issue 2

[Anton Moehammad via time-nuts]

Hi all,a few day ago I read "super HP5065A" from Mr Corby and I wondering if 
any one has done same thing with "telecom" Rubidium pack ? I found an optical 
bandpass filter cost is cheap enough to a third country people like me but if 
any one has tried before and know a lot more than what I know I really 
appreciate if You can share it  

Pada Rabu, 2 November 2016 23:00, "time-nuts-requ...@febo.com" 
 menulis:
 

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    time-nuts@febo.com

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When replying, please edit your Subject line so it is more specific
than "Re: Contents of time-nuts digest..."


Today's Topics:

  1. Re: Cs tube pics (Tom Van Baak)
  2. So what’s inside that Cs Beam Tube anyway? (Mark Sims)
  3. Re: Cs tube pics (Poul-Henning Kamp)
  4. Technical Paper: GPS Receiver Impact from the UTC Offset
      (UTCO) Anomaly of 25-26 January 2016 (Martin Burnicki)
  5. Re: Cs tube pics (Attila Kinali)
  6. Re: Cs tube pics (Poul-Henning Kamp)
  7. Re: Cs tube pics (Attila Kinali)
  8. OCXO's (ewkeh...@aol.com)
  9. Re: So what’s inside that Cs Beam Tube anyway? (paul swed)
  10. HP 105 and Piezo gone (ewkeh...@aol.com)
  11. Re: So what’s inside that Cs Beam Tube anyway?
      (Richard (Rick) Karlquist)
  12. Re: Cs tube pics (paul swed)
  13. Re: So what’s inside that Cs Beam Tube anyway? (paul swed)
  14. Re: So what’s inside that Cs Beam Tube anyway?
      (ewkeh...@aol.com)
  15. Re: So what’s inside that Cs Beam Tube anyway? (Peter Reilley)


--

Message: 1
Date: Tue, 1 Nov 2016 09:10:25 -0700
From: "Tom Van Baak" 
To: "Discussion of precise time and frequency measurement"
    
Subject: Re: [time-nuts] Cs tube pics
Message-ID: <6393D7A80E184F169329467E49E7F97E@pc52>
Content-Type: text/plain;    charset="utf-8"

Clint:
> While I've no need for such accuracy in my little home workshop,  I
> *really* would like a Cs standard,  just because.
> 
> The Rb and GPSDO are more than adequate for my needs but I can understand
> (and, for now, manage to resist) the addiction to accuracy and find it
> fascinating that such results can be achieved.

Attila:
> I really would like to do that. But they are a tad bit expensive.
> Especially on this side of the big pond. If anyone is willing
> to part with a Cs standard and want to have it a good home, feel
> free to contact me :-)

It's true that a cheap GPS receiver is more accurate long-term than a surplus 
cesium standard, but you're right about the "just because" part. To me at 
least, this time nut hobby is not so much about the pursuit of accuracy as it 
is an appreciation for the variety, ingenuity and complexity of timekeeping. In 
some cases "how it works" is far more interesting that "does it work".

A used but known working cesium standard can be expensive, but like most of you 
almost all my gear comes from eBay via automated daily keyword searches. Many 
of my mil- or telecom-surplus FTS 4050 and HP 5061 were obtained for just a 
couple hundred dollars. You may search for months or even years, but amazing 
bargains show up. Not all of them work, of course, but the op/svc manuals are 
superb, the design / construction is very repair-friendly, and there's a weird 
group called time nuts with helpful advice.

Plus once you get more than one unit you can mix parts and create your own 
Frankenstein. It turns out that many surplus cesium standards are not dead due 
to tube failures so its a very happy day when a beat up 5061 turns out to have 
only a failed power supply or a bad OCXO yet the tube is in perfect condition. 
I remember one person picked up a "dead" FTS cesium standard only to find the 
reason it didn't work is that the switch on the back was in standby mode! Only 
one time nut I know ever bought a replacement Cs tube new from the factory. All 
the rest of us sift through the graveyard looking for the one that cries "I'm 
not dead yet".

/tvb



--

Message: 2
Date: Wed, 2 Nov 2016 03:38:04 +
From: Mark Sims 
To: "time-nuts@febo.com" 
Subject: [time-nuts] So what’s inside that Cs Beam Tube anyway?
Message-ID:
    

    
Content-Type: text/plain; charset="Windows-1252"

You mean I can't just drill a hole in,  wash out the old cesium with some tap 
water ;-),  toss in some new cesium, suck out the air,  bung a cork in the 
hole, and call it a day?  Drat! foiled again...

---

> Because it's not that easy. We are talking about a high vacuum system here.

[time-nuts] Lucent RFTG-m-RB

[Anton Moehammad via time-nuts]

Hi All,I understand this RFTG-m-RB and RFTG-m-XO already discuss many-many time 
in the past but I need to ask for something that I don't clear enough..1. my 
GPS antenna position can give 6 to 8 satellite at once times with a good signal 
is that enough ?2. I believe the GPSDO and Rubidium are "comparable" in 
stability so I do not fully understand why I need Rubidium GPSDO ?3. I 
understand Rubidium has "lifetime" are this lifetime count from when its use or 
from its manufacture ?4. How good the psu I need ? I see inside of my RFTG-m-RB 
and RFTG-m-XO they use an DC to DC converter are 24v switch PSU is good enough 
or must I linear PSU ?5. How to sure my RFTG-m-RB and RFTG-m-XO combo are in 
spec ? 6. The best and the only calibration place I know here in Indonesia are 
Indonesia NMI with a PHM the cost for calibration is "not much" but the time is 
long (6 month) with 10-e10 maybe 10-e11 are this kind of calibration (without 
adjustment) is to much ?
Sorry for my Java English and for so many basic question.
Thank You
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[time-nuts] GPSDO unclear situation

[Anton Moehammad via time-nuts]

Hi All, 
My GPSDO based from VE2ZAZ design but I have a few question I do not clearly 
understand about GPSDO, like :
 1.How important the quality of 1 PPS signal based from jitter etc what the 
difference I will get between timing purpose GPS module like Ublox 6T or 
trimble resolution T with a position GPS module like ublox 6M or other in term 
of stability, accuracy and phase noise.
 2. I understand short time stability from OCXO is better than GPSDO ? can 
someone give me a clue what the time constant need for OCXO control (in my 
application 30 second) is that enough ?
3. I have few Rubidium oscillator and I read somewhere (I believe in KE5FX web) 
that GPSDO with rubidium osc is hard to beat, in what way ? short time, long 
time, phase noise.
My goal is "simple" I have access to national time reference lab ( an active 
Maser H ) I want to compare my reference to them off course there is no way I 
have same stability but anything not so "embrace" is fine to me 
Thank you for all opinion/advice.
Anton Hendra   
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[time-nuts] Bls: time-nuts Digest, Vol 130, Issue 38

[Anton Moehammad via time-nuts]

Dear All
This is the first time I posted in this forum so please forgive me if its 
already discuss before
I like to ask You who has more experience about my plan for USD75 GPSDO 
before I explain my plan let me tell You some real world limitation 
1. The parts I choose must be available in local store (custom bussiness cost a 
lot of time)
2. I do not aim for something special a magnitude better than my MTI milliren 
OCXO is welcome.

Now What in my mind 
I will use Ublox 7m GPS board that can program from 0,25Mhz to 10Mhz
(https://sites.google.com/site/g4zfqradio/u-blox_neo-6-7)

But the problem are I found someone 
(http://www.ra3apw.ru/proekty/ublox-neo-7m/) already do the spectrum analysis 
for this board and the result is like this :
and the last picture is far better, correct ? so what I need to do I have 2 
plan :
1. use the board 10Mhz output than use very narrow (100Hz bandwith) Crystal 
filter
2. Use the 4Mhz output than again filter it use Crystal filter to clean it than 
use it as reference for PLL for controling 10Mhz OCXO 
Which one you think a better way.
last I also like to know because MTI only spec the OCXO model 240 harmonics to 
down to -30dB (http://www.mti-milliren.com/pdfs/240.pdf) is there any benefit 
to use a crystal filter in the output to clearer it more.

any opinion is very welcome 
Thank You
Anton
 



 Pada Selasa, 26 Mei 2015 23:00, time-nuts-requ...@febo.com 
time-nuts-requ...@febo.com menulis:
   

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    time-nuts@febo.com

To subscribe or unsubscribe via the World Wide Web, visit
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When replying, please edit your Subject line so it is more specific
than Re: Contents of time-nuts digest...


Today's Topics:

  1. Re: Terrestrial Tides and Land Movement (Bob Camp)
  2. Re: Terrestrial Tides and Land Movement (Bob Stewart)
  3. pp2s? No, 1pps from a Nortel GPSTM! (Nathaniel Bezanson)
  4. Re: FTS 8400 (Gregory Beat)
  5. Re: 3048A software question (davidh)
  6. Re: LTC6957 internal architecture (David C. Partridge)
  7. Re: pp2s? No, 1pps from a Nortel GPSTM! (Tom Van Baak)
  8. Re: 3048A software question (Chuck Harris)
  9. Re: Terrestrial Tides and Land Movement (Chuck Harris)
  10. Re: TymServe 2100 1995 Issue - A Kludgy Fix (Esa Heikkinen)


--

Message: 1
Date: Mon, 25 May 2015 19:01:02 -0400
From: Bob Camp kb...@n1k.org
To: Bob Stewart b...@evoria.net, Discussion of precise time and
    frequency measurement time-nuts@febo.com
Subject: Re: [time-nuts] Terrestrial Tides and Land Movement
Message-ID: c83d4da8-3e3d-462f-abff-3dae1f645...@n1k.org
Content-Type: text/plain; charset=utf-8

Hi

Let’s step back a bit:

Your module is accurate to maybe 2 ns over a short period of time and something 
in the 10 to 20 ns range
over 24 hours. The 2 ns comes from a variety of issues. The 20 ns comes mainly 
from the ionosphere.

One example of a part of the 2 ns - the satellite positions in orbit are only 
known to some level of accuracy. The
data your module gets is a broadcast data set that represents a “best guess” 
made yesterday to fit the fight 
path today. 

A GPS that does an on the fly position solution to 3M is not that exceptional 
these days. You certainly see
claims of performance at the 1M or even 0.5M level. Yes people do fudge the 
numbers. Yes they do use WAAS
and the like to improve things. 

A 3M error is at most a 10 ns timing error. It’s more likely to be a 3-4 ns 
timing error. That’s not all that big compared to the numbers above. 

Am I fudging the numbers a bit? Of course I am. There is an implicit assumption 
that the mobile platform has
a good view of the sky. Dropping below 4 sats would not happen in this case. 
I’d also upgrade the LEA-6T to 
an LEA-8T (or similar). More sats is going to give you a better position 
solution. 

The bottom line is that an L1 GPSDO that wanders 10 to 20 ns per 24 hours 
compared to a Cesium or maser is 
doing pretty well. Taking that to 8 to 18 ns  vs 12 to 22 is a worthy thing to 
do. *Proving* that a specific  implementation better … maybe not so easy. I’ve 
seen a lot of plots of well respected eBay GPSDO’s that wander
30 ns or more (peak to peak) per day one day and 20 ns p-p the next….

Bob 



 On May 25, 2015, at 5:28 PM, Bob Stewart b...@evoria.net wrote:
 
 Hi Tom,
 I'm not sure what you mean by this 0D vs 3D.  I'm using an LEA-6T.  There are 
 three time transfer modes 0=disabled, 1=survey-in, 2=fixed mode.  Are you 
 suggesting that I set it to disabled to run a test?  I've never tried that.  
 I know that if I monitor the output while doing a survey, the phase is all 
 over the place.
 I'm in the middle of a therm correction test at the moment, but the plots at 
 the link