GPS module wanted for timing.

Started by Clive Arthur July 11, 2018
Hi

I need a GPS module which will give me:
...an accurate 10 MHz clock output
...an accurate 1 second pulse output
...a serial interface to read UTC.

(Position isn't important.  I know where I am.)

I know there are probably dozens of modules which will do this, but I 
have no experience in this area, so any advice would be welcome.  UK 
supplier preferred but not strongly.  Will need only a few.

Cheers
-- 
Clive
On Wednesday, July 11, 2018 at 11:02:27 AM UTC+2, Clive Arthur wrote:
> Hi > > I need a GPS module which will give me: > ...an accurate 10 MHz clock output > ...an accurate 1 second pulse output
What do you mean by "accurate"? Bye Jack
Am 11.07.2018 um 11:02 schrieb Clive Arthur:
> Hi > > I need a GPS module which will give me: > ...an accurate 10 MHz clock output > ...an accurate 1 second pulse output > ...a serial interface to read UTC. > > (Position isn't important.  I know where I am.) > > I know there are probably dozens of modules which will do this, but I > have no experience in this area, so any advice would be welcome.  UK > supplier preferred but not strongly.  Will need only a few.
Search the archives of the time nuts list. That has moved to a new server last week, so g**gl results may be outdated. The list is located at < http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > Myself, I'm running a HP58540A and a Lucent Z3811A/Z3812A pair. Both are not very mainstream. I have modded the Z3811A to drive a frequency doubler right from the 5MHz crystal oven. < http://www.hoffmann-hochfrequenz.de/downloads/DoubDist.pdf > Cheers, Gerhard
Gerhard Hoffmann wrote:
>Am 11.07.2018 um 11:02 schrieb Clive Arthur: >> Hi >> >> I need a GPS module which will give me: >> ...an accurate 10 MHz clock output >> ...an accurate 1 second pulse output >> ...a serial interface to read UTC. >> >> (Position isn't important.&nbsp; I know where I am.) >> >> I know there are probably dozens of modules which will do this, but I >> have no experience in this area, so any advice would be welcome.&nbsp; UK >> supplier preferred but not strongly.&nbsp; Will need only a few. > >Search the archives of the time nuts list. That has moved to a new >server last week, so g**gl results may be outdated. > >The list is located at < >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > >Myself, I'm running a HP58540A and a Lucent Z3811A/Z3812A pair. >Both are not very mainstream. > >I have modded the Z3811A to drive a frequency doubler right from the >5MHz crystal oven. >< http://www.hoffmann-hochfrequenz.de/downloads/DoubDist.pdf > > > >Cheers, Gerhard
Interesting, but a lot of big heavy metal.. I was wondering, I have several cheap ebay GPS modules with 1 Hz output that support both Chinese, Russian, and US GPS. 30 $ or so on ebay, but no 10MHz output. Been probing around in one of those (needed fixing) there _is_ a crystal, but not sure it is locked. Common chips... datasheet is available, cannot remember the exact number. I am thinking it should not be impossible to build a cheap divider and xtal oscillator and then phase lock it to the 1 pps (needs oven temperature stabilization). Depends indeed what you want to use it for. No need for that here, have a Rubidium 10MHz standard, also ebay.., good enough, and available 24/7 if needed, unlike GPS that may come and go some times, jamming.... There is also a 10MHz radio signal..
Clive Arthur <cliveta@nowaytoday.co.uk> wrote:
> Hi > > I need a GPS module which will give me: > ...an accurate 10 MHz clock output > ...an accurate 1 second pulse output > ...a serial interface to read UTC. > > (Position isn't important. I know where I am.) > > I know there are probably dozens of modules which will do this, but I > have no experience in this area, so any advice would be welcome. UK > supplier preferred but not strongly. Will need only a few. > > Cheers
It depends a lot on the accuracy you actually require (it cannot be indefinitely "accurate") and aspects like - has that accuracy to be documented and verified or is "chinese spec" OK - what behaviour do you require when GPS sync is lost for a while (which, together with the above, determines if you need some cesium or rubidium referenced unit or if OCXO or even TCXO is good enough) - are you looking for a small module to be used inside equipment, or a 19" module for a rack - how much money you want to spend For hobby/inexpensive I like the boxes made by Leo Bodnar, but he does not offer a model that fits your needs. Depending on what you actually require, you may be able to use one of them. Inexpensive modules are sold by the Chinese. Professional stuff costing thousands of dollars is widely available from professional equipment manufacturers working in this field.
On Wed, 11 Jul 2018 02:51:02 -0700, jack4747 wrote:

> On Wednesday, July 11, 2018 at 11:02:27 AM UTC+2, Clive Arthur wrote: >> Hi >> >> I need a GPS module which will give me: >> ...an accurate 10 MHz clock output ...an accurate 1 second pulse output > > What do you mean by "accurate"? >
Normally, in the context of GPS, the word "accurate" would normally be regarded as being somewhat redundant. Presumably an accuracy measured in nanoseconds is being sought. :-) -- Johnny B Good
On Wed, 11 Jul 2018 10:56:14 GMT, <698839253X6D445TD@nospam.org>
wrote:

>Gerhard Hoffmann wrote: >>Am 11.07.2018 um 11:02 schrieb Clive Arthur: >>> Hi >>> >>> I need a GPS module which will give me: >>> ...an accurate 10 MHz clock output >>> ...an accurate 1 second pulse output >>> ...a serial interface to read UTC. >>> >>> (Position isn't important.&nbsp; I know where I am.) >>> >>> I know there are probably dozens of modules which will do this, but I >>> have no experience in this area, so any advice would be welcome.&nbsp; UK >>> supplier preferred but not strongly.&nbsp; Will need only a few. >> >>Search the archives of the time nuts list. That has moved to a new >>server last week, so g**gl results may be outdated. >> >>The list is located at < >>http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> >>Myself, I'm running a HP58540A and a Lucent Z3811A/Z3812A pair. >>Both are not very mainstream. >> >>I have modded the Z3811A to drive a frequency doubler right from the >>5MHz crystal oven. >>< http://www.hoffmann-hochfrequenz.de/downloads/DoubDist.pdf > >> >> >>Cheers, Gerhard > >Interesting, but a lot of big heavy metal.. > >I was wondering, I have several cheap ebay GPS modules with 1 Hz output >that support both Chinese, Russian, and US GPS. >30 $ or so on ebay, but no 10MHz output. >Been probing around in one of those (needed fixing) there _is_ a crystal, but not
sure it is locked.
>Common chips... datasheet is available, cannot remember the exact number. > >I am thinking it should not be impossible >to build a cheap divider and xtal oscillator and then phase lock it to the 1 pps
(needs oven temperature stabilization).
>Depends indeed what you want to use it for. >No need for that here, have a Rubidium 10MHz standard, also ebay.., >good enough, and available 24/7 if needed, >unlike GPS that may come and go some times, jamming.... >There is also a 10MHz radio signal..
GPSDO <https://www.amazon.com/YEDEMC-output-disciplined-antenna-supply/dp/B01J7QTSEQ> Cheers
Clive Arthur <cliveta@nowaytoday.co.uk> wrote in news:pi4h30$92u$1@dont-
email.me:

> Hi > > I need a GPS module which will give me: > ...an accurate 10 MHz clock output > ...an accurate 1 second pulse output > ...a serial interface to read UTC. > > (Position isn't important. I know where I am.) > > I know there are probably dozens of modules which will do this, but I > have no experience in this area, so any advice would be welcome. UK > supplier preferred but not strongly. Will need only a few. > > Cheers
Devices like that are typically in the form of a 1U rack mount package. One will not find many portable or handheld units providing such features. And if you do it will likely be prohibitively expensive.
AT Wednesday 11 July 2018 17:02, Clive Arthur wrote:

> Hi > > I need a GPS module which will give me: > ...an accurate 10 MHz clock output > ...an accurate 1 second pulse output > ...a serial interface to read UTC. > > (Position isn't important. I know where I am.) > > I know there are probably dozens of modules which will do this, but I > have no experience in this area, so any advice would be welcome. UK > supplier preferred but not strongly. Will need only a few. > > Cheers
uBlox has modules for that <https://www.u-blox.com/en/product/neolea-m8t-series> -- Reinhardt
On Wed, 11 Jul 2018 12:23:34 GMT, Johnny B Good
<johnny-b-good@invalid.ntlworld.com> wrote:

>On Wed, 11 Jul 2018 02:51:02 -0700, jack4747 wrote: > >> On Wednesday, July 11, 2018 at 11:02:27 AM UTC+2, Clive Arthur wrote: >>> Hi >>> >>> I need a GPS module which will give me: >>> ...an accurate 10 MHz clock output ...an accurate 1 second pulse output >> >> What do you mean by "accurate"? >> > Normally, in the context of GPS, the word "accurate" would normally be >regarded as being somewhat redundant. Presumably an accuracy measured in >nanoseconds is being sought. :-)
The fundamental GPS output is the 1 PPS pulse. It jitters and wanders around a lot, as satellites come and go and the atmosphere changes. It's accurate long-term, so you can lock a very good oscillator to it, slowly, and get a good 10 MHz. The slower the lock loop and the better the oscillator, the better 10M. A rubidium is good. Cheap GPS receivers can have 1PPS jitter in the ballpark of a microsecond. -- John Larkin Highland Technology, Inc lunatic fringe electronics