Re: [time-nuts] Advise on building a DIY GPSDO?

Hi …. and this fulfills the requirement I mentioned: “I just want to build one to say I’ve done it” There is *absolutely* nothing at all wrong with that. If this is your goal, you have accomplished it. You likely have learned somethings along the way. If you have a performance goal that is

Re: [time-nuts] Advise on building a DIY GPSDO?

and it is relative easy to make 10MHz from 8MHz with analog frequency manipulation, which generates less jitter 73 On 4/4/2016 4:27 PM, Attila Kinali wrote: On Mon, 4 Apr 2016 17:56:29 -0400 Bob Camp wrote: The variable frequency output on the uBlox (and other) GPS receivers

Re: [time-nuts] Advise on building a DIY GPSDO?

Lots' of help herein; ...but, also lots' of nay-sayers, too. Don't let the nay-sayers scare you. A VERY accurate, newbie-based, GPSDO can be built with minimal investment or cost. It's not hard at all. Just Do-It. Mistakes allowed. I have built two GPSDO's from scratch. Both worked very

Re: [time-nuts] Advise on building a DIY GPSDO?

Hi Even with an integer divide, it’s still going to toss in a full cycle of the TCXO from time to time. It will be an integer, except when it is not …. Bob > On Apr 4, 2016, at 7:27 PM, Attila Kinali wrote: > > On Mon, 4 Apr 2016 17:56:29 -0400 > Bob Camp

Re: [time-nuts] Advise on building a DIY GPSDO?

On Mon, 4 Apr 2016 17:56:29 -0400 Bob Camp wrote: > The variable frequency output on the uBlox (and other) GPS receivers > has come up many times in the past. > If you dig into the archives you can find quite a bit of data on the > (lack of) performance of the high(er) frequency

Re: [time-nuts] Holdover recovery

Yes, very interesting, good to have. I see differences: the most notable is the plot of page 12 on the original italian version that is missing on the ITU paper, that goes with the figure 4 on page 7 (of the ITU one). On Tue, Apr 5, 2016 at 12:57 AM, Magnus Danielson

Re: [time-nuts] Advise on building a DIY GPSDO?

Hi The variable frequency output on the uBlox (and other) GPS receivers has come up many times in the past. If you dig into the archives you can find quite a bit of data on the (lack of) performance of the high(er) frequency outputs from the various GPS modules. They all depend on cycle add /

Re: [time-nuts] Advise on building a DIY GPSDO?

Building it cost you time and money, most likely much more than to buy, but you gain experience and you learn the limits of the different techniques, what you would not get to know other way 73 KJ6UHN Alex On 4/4/2016 1:15 PM, Dimitri.p wrote: Regarding "as good a place to start as any",

Re: [time-nuts] Holdover recovery

Hi, I had not seen the ITU-R version, nice. I have their paper and shared it with Hal on the side. This ITU-R version seems about the same, but I've got their names on it. I got a copy of their paper in english without their names on it, which might have been their input contribution to

Re: [time-nuts] Holdover recovery

Hi On a surplus cell phone GPSDO it’s going to be: 1) System has been down for a while (= something failed) 2) System is now working ( = something was fixed) 3) The primary system spec must now be met (+/- 100 ns time alignment). 4) The secondary system spec should be met (+/- 5x10^-8

Re: [time-nuts] Holdover recovery

My Italian is not very good, but I think this is the English translation via ITU: https://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2253-2012-PDF-E.pdf -Logan On Mon, Apr 4, 2016 at 1:10 PM, wrote: > Here the italian version: > >

Re: [time-nuts] Holdover recovery

The only english text I'm able to find is: Analysis of the GPS frequency reference stability Laboratory analysis of the dynamic behaviour of some GPS receivers has allowed to identify a criticality in their use as ‘clocks’ to synchronize DVB-T SFN networks. To fix this criticality, the Research

Re: [time-nuts] Holdover recovery

Here the italian version: http://www.crit.rai.it/eletel/2012-1/121-2.pdf Luciano www.timeok.it On Mon 04/04/16 21:28 , Magnus Danielson wrote: > Hi Hal, > > On 04/04/2016 05:39 AM, Hal Murray wrote: > > > > Has anybody studied what happens when a GPSDO comes out

Re: [time-nuts] Holdover recovery

In italian: Can't find it in english... On Mon, Apr 4, 2016 at 9:28 PM, Magnus Danielson wrote: > Hi Hal, > > On 04/04/2016 05:39 AM, Hal Murray wrote: >> >> >> Has anybody studied what happens when a GPSDO comes out of

Re: [time-nuts] Advise on building a DIY GPSDO?

Regarding "as good a place to start as any", ublox receivers will do 10KHz all day long. I didn't realize ublox receivers have dual output until after I built a couple of other GPSDOs, (well, maybe four) As for a good OCXO: other than the Morion MV89a, ($20-$50) for anything else, figure

Re: [time-nuts] Advise on building a DIY GPSDO?

As a victim of the "I'm gonna build a GPSDO" virus, I think the cautions are well worth mentioning. Building a decent GPSDO sounds like such a simple thing, but it slowly turns into a rabbit hole as you discover you need ever better test equipment, and a microscope, and hot air rework station,

Re: [time-nuts] Advise on building a DIY GPSDO?

On Mon, April 4, 2016 11:18 am, Tom Holmes wrote: > The preceding questions always come up when a newbie > comes up on the list wanting to build their own GPSDO. It is good to make sure the person actually wants to build a GPSDO. A few years back I was in a similar position, and my answer was I

Re: [time-nuts] Holdover recovery

Hi Hal, On 04/04/2016 05:39 AM, Hal Murray wrote: Has anybody studied what happens when a GPSDO comes out of holdover? Has anybody seen any specs? I don't think I have. I think you have a choice of quick recovery for time or frequency, but you can't get both. Suppose your setup has been in

Re: [time-nuts] Advise on building a DIY GPSDO?

The preceding questions always come up when a newbie comes up on the list wanting to build their own GPSDO. They are all good questions from an engineering/management viewpoint, but this latest incident reminded me of conversations I had with my father some 50+ years ago when I wanted to tackle

[time-nuts] Replacement Oncore Modules - all gone for now

The demand has been much more then I expected, and didn't expect almost everyone one to want two. I had no idea there were so many old HP units out there. I do not know if I can fulfil all the requests. Packages will be sent FIFS "First In First Shipped". Again if I do not have an address that

Re: [time-nuts] Holdover recovery

On 4/3/16 8:39 PM, Hal Murray wrote: Has anybody studied what happens when a GPSDO comes out of holdover? Has anybody seen any specs? I don't think I have. I think you have a choice of quick recovery for time or frequency, but you can't get both. Suppose your setup has been in holdover for

Re: [time-nuts] Holdover recovery

> Le 4 avr. 2016 à 05:39, Hal Murray a écrit : > > > Has anybody studied what happens when a GPSDO comes out of holdover? Has > anybody seen any specs? I don't think I have. > > I think you have a choice of quick recovery for time or frequency, but you > can't get

Re: [time-nuts] Holdover recovery

The chinese GPSDO's famous on E-bay are not really phase locked to begin with, they are only frequency locked and often with a small frequency offset. I don't think any of your questions apply to this kind of unit. See e.g. http://www.ke5fx.com/gpscomp.htm Units that have been spec'ed for

Re: [time-nuts] Advise on building a DIY GPSDO?

> Lots of branches and that’s only two questions. Another interesting question is how good is your antenna? If your antenna is great and you can tolerate occasional off time, you don't need to pay much attention to holdover. -- These are my opinions. I hate spam.

[time-nuts] Holdover recovery

Has anybody studied what happens when a GPSDO comes out of holdover? Has anybody seen any specs? I don't think I have. I think you have a choice of quick recovery for time or frequency, but you can't get both. Suppose your setup has been in holdover for a while. The frequency is slightly